Nanochemistry and Thechnology

Transcription

Iranian Physical Chemistry
Conference
University Of Mazandaran
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‫ﺷﺎ د ﻦ ا ﺲ ﯽ ﺰﯾﮏ ا ان‬
١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
‫ه ﯽ‬
‫ دا‬،‫ دا ه ﻣﺎز ﺪران‬،‫ﺑﺎﺑ ﺮ‬
Nanochemistry and
Thechnology
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Conference
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Effect of Silver Nanoparticles on the Crystallinity Behavior of
Polyethylene
M. Abareshi* and S.M. Shahroodi
Dept. of Chemistry, Payame Noor University, 19395-3697 Tehran, I. R. of Iran
Email: [email protected]
Keywords: PE-Ag nanocomposite, Mechanical milling, XRD technique, Degree of Crystallinity.
Introduction
The degree of crystallinity is an important parameter for semicrystalline polymers. Many physical
and mechanical properties of polymers are significantly dependent on the degree of crystallinity [1].
Thus, the purpose of this study is to evaluate the degree of crystallinity of PE and its
nanocomposites by the XRD method.
Methods &Characterization
Nanocomposites were prepared by mechanical milling of the PE and Ag NPs in a mixer mill. PE
and 5, 10, 20, and 30 wt% of Ag were mechanically mixed first and then milled for 15 min. The
XRD analysis was carried out in order to study the crystallinity of pure PE and PE-Ag
nanocomposites.
Results and discussion:
Fig. 1a shows the SEM image of PE-Ag10 % nanocomposite. As shown in this figure, Ag NPs are
well dispersed on the surface of PE matrix. Fig. 1b illustrates the energy dispersive X-ray
spectroscopy analysis of nanocomposite, which is performed in one of the small particles for
confirmation of Ag NPs presence in the PE matrix.
Fig. 1.(a) SEM image of PE-Ag 20% nanocomposite and (b) energy dispersive X-ray spectroscopy analysis of
marked smallparticle.
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Fig. 2 shows the XRD patterns of PE-Ag5% and PE-Ag30 % nanocomposites. This figure also
confirmed the incorporation of Ag in the nanocomposites. As shown in Fig. 2a and 2b, two
crystalline peaks at 2θ of 21.67o and 24.04owas ascribed to the PE. Above 30o, four additional
diffraction peaks were observed, which further indicated the existence of Ag NPs in the
nanocomposites.
Fig. 2.The XRD patterns of (a)PE-Ag 5% and
Fig. 4.The XRD patterns of PE and PE-Ag
(b)PE-Ag 30% nanocomposites.
nanocomposites.
The XRD of PE and PE-Ag nanocomposites with different weight percents of Ag are shown in Fig.
3. As this figure shows, the peaks of PE do not shift by adding different amounts of Ag. It implies
that all matrix nanocomposites have the same crystal structure, and Ag NPs cannot change the
crystal structure. With the Ag loading, the peaks have become wider and their intensities have
considerably decreased. It shows that the crystallinity of PE has decreased as the Ag contents have
increased. The degree of crystallinity of samples was quantitatively estimated using the method of
Nara and Komiya [2].Table 1 shows the degree of crystallinity (Xc) of PE. The degree of
crystallinity of PE decreases as the Ag NPs content increases.
Table 1.The degree of PE crystallinity.
Sample
PE
PE-Ag%10
PE-Ag%30
Xc
41.76
39.94
35.1
Conclusions
The method of mechanical milling has been used to fabricate PE-Ag nanocomposites containing
different Ag contents. The XRD results show that the crystallinity of PE decreases as the Ag weight
percent increases, whereas the crystal structure does not change.
References
[1] M. Abareshi, J. Compos. Mater., 43, 2821-2830, 2009.
[2] W. Shujun, et al. Am. J. Biochem. Biotechnol., 1, 207-211, 2005.
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Structural and Dynamical Properties of Nanoconfined Polystyrene
Oligomers: a Molecular Dynamics Study
Ali Rafi Dargahi * ,1 , Hassan Behnejad 1 , Hossein Eslami 2
1
Department of Chemistry, College of science, University of Tehran, Tehran, Iran
2
Department of Chemistry, College of science, Persian Gulf University, Boushehr, Iran
*
E-mail: [email protected]
Keywords: Nanoconfined Polystyrene oligomers, Molecular dynamics simulation, NAPT
ensemble method
Introduction
Confined nanoscale fluids occur in technologically important processes such as adsorption,
lubrication, adhesion, coating, wetting, spreading, chromatography, and membrane separation.
Common to these processes is the presence of fluid films that are under the strong influence of
confining walls. In fact, confining a fluid between two solid surfaces, whose separations are just a
few molecular diameters affects significantly both equilibrium and nonequilibrium properties of
fluids. The experimental works on the confined fluids are very difficult to perform, due to the
existence of only a small amount of material in the confined region. In this work we have employed
a new molecular dynamics simulation technique to study the structure and dynamics of confined
polystyrene oligomers between graphene surfaces.
Method
The isosurface-isothermal-isobaric (NAPT) ensemble simulation technique [1] is a method in which
only the confined region is simulated at a constant number of molecules, N, constant surface area,
A, constant temperature, T, and constant parallel component of pressure,
∥.
In this method, the MD
simulation method of Berendsen [2] with coupling to an external bath is extended to keep the
parallel component of pressure fixed by changing the distance between the confining surfaces.
In this work several nanoconfined systems in which the number of polystyrene oligomers varies
between 70 and 100 are simulated. To be able to calculate properties of confined oligomers as a
function of surface separation, we change the number of surface atoms and the number of oligomers
in glassy and melt form. Moreover we have further simulated a bulk sample of polystyrene to
compare the effect of confinement on the properties of nanoconfined polystyrene. Allsimulations
were carried out using the YASP simulation package. The simulations performed in two different
temperatures (300 K and 400 K) and fixed at these temperatures using a Berendsen thermostat with
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a temperature coupling time of 0.2 ps.
‫ه ﯽ‬
∥
was kept constant at 101.3 kPa with a pressure coupling
time of 5.0 ps, employing the method described in detail in ref. [1].
Results and Discussions
The local density profiles of oligomers that calculated based on the position of all atoms in
the simulation box shows that as the surfaces get closer, the oligomers form well-layered
configurations parallel to the surfaces. However, the number of well-formed layers changes with the
surface separation.
Analysis of end-to-end vector alignments shows that the oligomers adopt a flatted conformation
near the surfaces and study of local dynamics via calculating autocorrelation functions for bins
parallel to the surfaces reveals that the fluid layers close to the surfaces have higher relaxation times
than the fluid in the central region. The center of mass diffusion coefficients of confined oligomers
are obtained as well (Figure 1).
Figure 1.center-of-mass men-square displacement for a system consisting 90 polystyrene oligomers confined between
grapheme surfaces.
The results indicate that the parallel component of diffusion coefficient shows oscillatory behavior
with local minima at distances corresponding to well-formed structures and local maxima at
distances corresponding to distances at which the well-formed layers cannot develop due to
incommensurability with the slit width.
Conclusion
We studied structural and dynamical properties of nanoconfined polystyrene oligomers using a
molecular dynamics technique with constant temperature, surface area, and parallel pressure. In
general, we calculated and predicted some comprehensive information of polymer behavior in the
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interface of polymer-graphene nanocomposites which many of them are not measurable by
experimental methods.
References
[1] H. Eslami, F. Mozaffari, J. Moghadasi, F. Müller-Plathe, J. Chem. Phys. 129 (2008) 194702.
[2] H. J. C. Berendsen, J. P. M. Postma, W. F. Van Gunsteren, A. DiNola, and J. R. Haak, J. Chem. Phys.
81(1984) 3684.
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Comparing the properties of carbon and boron nitride nanotubes as drug
carriers: a molecular dynamics simulation
E. Sedghamiz*, E. Jamalizadeh, S.M.A Hosseini
Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76175, Iran
Keywords: Molecular dynamics simulation, Boron nitride nanotube, Carbon nanotube,
Mechlorethamine.
Introduction
Drug delivery has been greatly improved over the years by means of chemical and physical agents
that increase bioavailability, improve pharmacokinetic, reduce toxicities and interact with biological
barriers. Boron nitride nanotubes (BNNTs) are nanostructured compounds like carbon nanotubes
(CNTs), having a graphite-like sheet structure constituted by alternating B and N atoms. Compared
with the CNTs, BNNTs nanotubes not only have high thermal conductivity but also high oxidation
resistivity as well as high thermal and chemical stability [1, 2]. In the present study, our aims are
examination of the structure, orientation, conformation and solvation of the anticancer drug
Mechlorethamine inside pristine single-walled zigzag (10,0) boron-nitride and carbon nanotubes in
aqueous solution using a molecular dynamics simulation approach.
Method
Zigzag (10,0) single-walled BNNT and CNT with 25 Å length and 240 atoms were optimized using
semiempirical-PM3 method. Then, electrostatic potentials of atoms were computed using DFTB3LYP method and 6-31G** basis set. The molecular structure of anticancer drug mechlorethamine
was also optimized at the DFT-B3LYP level of theory using the 6-31G** basis set.The molecular
dynamics simulations were carried out for free Mechlorethamine and its complex with BNNT and
CNT solvated in an aqueous solution. The simulation was performed using DL-poly program
packagewith the Canonical (NVT) ensemble at 1 atm and 311 K using Berendsen thermostat.
Results and discussion
Energy plots show the stability of the drug inside BNNT whilst the drug-CNT system was unstable.
In addition outputs of simulation depict that during simulation time mechlorethamine stays inside
BNNT but for CNT it doesn’t happen and drug comes out of carbon nanotube. It also shows
movement of drug toward one ends of BNNT from the first displacement during simulation
process. It can be realized that CNT is not a suitable carrier for delivery of mechlorethamine. For
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BNNT, two systems have been considered; that of mechlorethamine inside the BNNT, and that of
drug in the free state. The molecular alignment of drug inside BNNT was calculated using RDF
plots. The obtained value of 8.37˚indicates the tilted angle of drug with the inner surface of BNNT.
Solvation of drug inside BNNT and in the free state were compared using RDF plots (fig.1). Water
molecules in the first hydration shell bind stronger to the drug atoms in the complex form than
those in the free form. Moreover, there were no considerable changes in conformational parameters
of drug inside BNNT comparing to drug in free state.
(a)
(b)
Fig.1. Radial distribution functions, g(r), (a) centered on the chlorine atom of mechlorethamine to the oxygen atoms of
the modeled water for (b) centered on the nitrogen atom of mechlorethamine to the oxygen atoms of the modeled water
in the free and BNNT-complexed systems.
Conclusion
MD simulation has proved to be a useful tool to investigate the conformation, orientation and
solvation of anti cancer drug, mechlorethamine, encapsulated in the single walled boron nitride and
carbon nanotubes. These properties were extensively investigated in comparison to those of the
drug in the free solvated state. Results show that BNNT is a suitable carrier for delivery of drug
mechlorethamine comparison to CNT.
References
[1] F. Pierigè et al., Advan. Drug Delivery Rev. 60, 286-295, 2008.
[2] G. Ciofani et al., J. Colloid Interface Sci. 374, 308 -314, 2012.
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Preparation and Thermal characterization of epoxy/1,4-Bis(3aminopropoxy) butane/MWCNT nanocomposite
S.Khostavan * a , A. Omraniband A. A .Rostamia
Faculty of Chemistry, University of Mazandaran, Babolsar, Iran
[email protected]
Keywords: Theromosetting resin, MWCNT, NMR, Thermal analysis, Thermal stability,
Abstract
This paper presents results of the processing and characterization of nanocomposites based on
epoxy and MWCNT (up to 10 wt %). The nanocomposites show increased thermal degradation
properties, tensile strength, and glass transition temperature.
Introduction
Epoxy-based polymers are widely used in applications ranging from microelectronics to the
aerospace industry and they can be made reinforced by the addition of various types of nano
particles like MWCNT that in recent years, researchers have paid much attention on it.
Methods
At first the exact equivalent weight of the DGEBAD.E.R 332epoxy resin was evaluated by means
of NMR method. NMR spectrum is shown in Figure 1-a and by using the equation 1-3 the
equivalent weight of the epoxy resin could be exactly determined. I2 is related to intensity of a and b
protons and I2 is proton intensity of e, f and g. The equivalent weight obtained 174.9842 g/eq which
was approximately near the reported weight (175 g/eq).
1) EEW=142N+170
,
2) N= (Rp–Rt)/Rt=(Rp-1.33(/1.33,
3) Rp=I2/I1
So we need 0.28 cm3 hardener for each gram of sample. Then 1 g of epoxy was dissolved in 1 ml of
THF and then optimum weight of carbon nanotube (found to be of 5% MWCNT by dynamically
cured samples) dispersed into the solution by ultrasonication for 45 min. then the 0.28 cm3 of
diamine was added and stirred mechanically for 30 min followed by ultrasonication for 15 min. For
DMTA measurements samples were prepared in the same way and then heated in a vacuum oven at
60 and 150 oC for 60 and 180 min, respectively. Dynamic mode TGA experiments were conducted
in the range of 25-750 °C at heating rates of 10, 20, 30 and 40 K/min.
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TGA curves of the neat epoxy and MWCNT nanocomposites showing two main degradation stages
at about 320 and higher than 500 oC showing that introducing raw MWCNT enhances the initial
decomposition temperature of the matrix. Kissinger method was utilized to analyze the TGA data:
4) ln
ln
ln n 1
α
Where, β is the heating rate, A is the pre-exponential factor, αmax is the maximum conversion, and n
is the reaction order. From the slope of ln(β/T2max) versus 1000/Tmax the activation energy can be
calculated (Figure 1b) and found to be 221.41 and 125.77 kJ/mol for the nanocomposite and neat
epoxy systems, respectively. Obviously, MWCNT increased the Ea of thermal decomposition
process demonstrating lower decomposition rate.
Figure 1a)NMR plot of DGEBAD.E.R 332 epoxy resin, b) The Kissinger plots for the pure epoxy and nanocomposite, c)
Storage modulus (E0) as a function of temperature, d) Curves of tanδ against temperature
DMTA analysis was done at fixed frequency to investigate the Tg and viscoelastic properties. The
Tg of nanocomposite is about 83.9 oC while is 76.9 oC for neat composition showing an effect on
the rubbery regions by adding nanotubes to the matrix. Also, an increase in the storage modulus in
the glassy region and in the vicinity of the Tg was seen. Improved interaction between MWCNT and
the epoxy matrix due to enormous surface area leads to strong shift of the elastic properties below
the rubbery region.
Conclusions
TGA studies presents that thermal decomposition temperature increased in the nanocomposite
having the optimum concentration of MWCNT. The DMTA studies revealed that the Tg of
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epoxy/1, 4-Bis (3-aminopropoxy) butane is 76.9 oC and increases to be 83.9 oC at the presence of
MWCNT.
References
[1] Gerson AL, Bruck HA, Hopkins AR, Segal KN., Compos Part A: Appl Sci Manuf 2010;41:729–36.
[2] Chen CH, Jian JY, Yen FS. , Compos Part A: Appl Sci Manuf 2009; 40:463–8.
[3] Chatterjee A, Islam MS., Mater Sci Eng A 2008; 487:574–85.
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First- principal study of hydrogen storage on AgC 60
F. Abdi and K. Azizi*
Department of Chemistry, University of Kurdistan, Sanandaj, Iran
(Email:[email protected])
Keywords: Hydrogen storage, Metalofullerens, Dewar-Kubas mechanism
Introduction
Increasing threats posed by the consumption of fossil fuels requires our planet to adopt new
strategies to control the inexhaustible sources of energy. In recent years, transition metal-decorated
fullerenes (TMDF), a kind of hydrogen sorbents material, have been studied extensively [1,2]. The
vast majority of previous studies have been devoted to light metal TMDFs. Although, the
application of heavy transition metal atoms in TMDFs may reduce the mass percent of adsorbed H2,
however, it can highlight new aspects of the mechanism of absorption of H2 on TMDF. For
example, while according to Dewar-Kubas mechanism [3] the positive charge of the metal atom
responsible for hydrogen adsorption, it was not clear why the adsorption energy of hydrogen
molecules on transition metal atoms is higher than that of alkali and alkaline earth metals. In this
study the interaction of hydrogen molecules with AgC60 complex, which has recently proven to be
stable at ambient conditions [4] have studied. The possible role of the van der Waals forces on the
hydrogen adsorption on metal decorated systems was discussed.
Computational details
All of the structures were fully optimized without any symmetry limitation using the B3LYP
method with 6–311G** basis set for carbon and hydrogen atoms and LanL2DZ basis set for silver
atom. As the B3LYP method poorly estimates the van der Waals forces, MPW1PW91 method, was
applied to calculate hydrogen adsorption on AgC60 [5].
The average binding energy per
H2molecule, Eb , H was computed by using the following equation:
2
(1) Eb , H  {[ E AgC
2
where E AgC
60
(H 2 )n 
60
(H 2 )n 
 [ E AgC 60   nE  H 2  ]} / n
, E AgC  and E  H  are the results of single point calculations and n is the number of
60
2
H2 molecules adsorbed on AgC60 .
Results and Discussion
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At first, one H2 molecule is placed in the distance of 3Å from Ag atom at different initial
geometries including; over Ag atom (O), nearest hexagon rings to the Ag atom (H1, H2 or H3) and
on the pentagon ring (P) which are shown in Fig. 1. The geometry optimization of AgC60H2
complex led to three stable configurations as depicted in Fig. 1.
(a
b1(Ov-Ag)
b2(Op-Ag)
b3(S-
Fig. 1.Different initial geometries for H2 adsorption on AgC60 (a), three stable configurations and charge density for
adsorption of a hydrogen molecule on AgC60 (b1-b3).
As can be seen from the data given in Table 1the configurations in which H2 placed over Ag atom
(Ov-Ag or Op-Ag) are more stable than S-Ag in which H2 placed on one side of the Ag atom.
Although the Dewar-Kubas mechanism can justify why Ov-Ag and Op-Ag configurations are more
stable than S-Ag, however, it can not be used to explain the stability of Ov-Ag configuration with
respect to the Op-Ag.A close look at the Fig.1 (b1 to b3) indicates that unlike the Ov-Ag and Op-Ag,
in S -Agconfigurationthe charge density only covers AgC60. Therefore, we expects that alongside
the electrostatic forces, the role of dispersion forces should be considered.
Table 1.The structural and electronic parameters of adsorption of H2 on AgC60.
AgC6
0 H2
Configuration
Ov-Ag
Op-Ag
S-Ag
AgC60(H2)2
AgC60(H2)9
Eads (eV)
-0.303
-0.253
-0.196
-0.252
-0.085
Ag-H2 (Å)
2.07
2.19
2.36
2.21
2.014
H-HElongation (Å)
0.014
0.018
0.010
0.010
0.003
Q(Ag) |e|
0.503
0.527
0.450
0.492
0.179
Q(H2) |e|
-0.061
-0.102
-0.008
-0.052
-0.051
The adsorption of second to the ninth H2 molecule on the optimized AgC60(H2) complex was also
studied. According to data given in Table 1 the binding energy of H2 molecules to the AgC60, Eads,
is in the range has been proposed by the U.S. department of energy. As we can see, there is direct
relation between the values of Eads and electrical charge accumulated on Ag atom in AgC60.
References
[1]. Shevlin, S. A.; Guo, Z. X., Chem. Soc. Rev.,2009, 38, 211.
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[2]. Venkataramanan, N.S.; Note, R.; Sahara, R.; Mizuseki, H.; Kawazoe, Y., Chem. Phys. 2010,
377, 54.
[3]. Sun, Q.; Wang, Q.; Jena, P.; Kawazoe,Y.;J. Am. Chem. Soc., 2005, 127, 14582.
[4]. Azizi, K.; Sohrabinia, A.;Journal of J. Mol. Grap. and Model., 2012, 38, 354.
[5]. Krasnov, P. O.; Ding, F.; Singh, A. K.; Yakobson, B. I.,J. Phys. Chem. C, 2007, 111,17977.
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Fast and efficient azo dye removal using engineered Fe/Pd bimetallic
nanoparticles: Kinetics and thermodynamics studies
S. Samiee* a , E.K. Goharshadi a , P. Nancarrow b
a
Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779, Iran ([email protected]; E-mail)
b
Department of Chemical Engineering, American University of Sharjah, Sharjah, UAE
Keywords: Fe/Pd bimetallic nanoparticles, Kinetic study, Thermodynamic study, RB5
degradation mechanism
Introduction
Water pollution is one of the most important environmental problems in human societies. It mainly
arises from wastewater released from household, industrial, and agricultural processes. These
effluents typically contain high concentrations of organic and inorganic chemicals such as
hydrocarbon solvents, heavy metals, dyes, pesticides, and so on [1]. Azo dyes, one of the greatest
groups of synthetic dyes, are widely used in many industries. Therefore, removal of azo dyes from
colored effluents of industeries has attracted great interest due to their complex composition,
toxicity, poor degradability, and high solubility [2]. Zero-valent iron (ZVI) nanoparticles (NPs)
have been used as reactive medium for wastewater treatment because the iron metal is low-cost,
easy-to-obtain, and environmentally friendly [3,4]. However, nano ZVI shows some shortcomings
such as low reactivity and incomplete degradation due to the formation of oxide layers which block
the surface active sites [4]. An appropriate technique to overcome this limitation is combining a
second metal to ZVI to design a bimetallic system which can benefit from the features of both
monometals simultaneously.
Our goals of the present work are to prepare Fe/Pd bimetallic NPs, investigate the ability of these
NPs for an azo dye removal, and study the kinetics and thermodynamics of the process.
Methods
Fe/Pd NPs were synthesized by successive reduction method. FeSO4.7H2O and palladium acetate
were used as the precursors of Fe and Pd and NaBH4 as the reduction agent.
In this work, successive reduction method was used for deposition of a trace amount of Pd on nano
Fe surface to produce engineered Fe/Pd bimetallic NPs. Ten characterization methods such as X-ray
diffraction, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, transmission
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electron microscopy (TEM), high resolution TEM, and BET surface area analysis were used to
clarify the formation of Fe/Pd bimetallic NPs and to confirm the presence of Pd on the surface of Fe
NPs. The ability of Fe/Pd NPs for removal of an azo dye, Reactive Black 5 (RB5), was
investigated. RB5 was selected as a pollutant model due to its wide usage in textile industry. The
influence of Fe/Pd dosage, pH, temperature, and initial dye concentration on the dye removal
process was studied. The synergetic effect of Pd on Fe leads to an efficient and fast dye removal
process, i.e, the maximum dye removal (100%) was achieved for 20.0 mg Fe/Pd, pH=3.0, and the
dye concentration of 20 ppm at 25 oC in less than 15 min. Kinetic studies showed that RB5 removal
using Fe/Pd bimetallic NPs obeys the pseudo-first order kinetic model. Thermodynamic study of
RB5 removal revealed that the process was spontaneous (ΔG= -8.32 kJ mol-1) and exothermic (ΔH=
-4.06 kJ mol-1). The HPLC-MS technique was used to propose a possible mechanism for RB5
degradation. The results confirm that dye molecules are reduced to smaller aromatic compounds via
cleavage of azo bonds without producing more hazardous materials.
Conclusion
The ability of iron NPs for an efficient degradation of RB5 dye was improved by deposition of a
trace amount of Pd NPs on Fe surface. The results showed that the acidic pH, increasing dosage of
NPs, and low temperature favour the removal of RB5. Also, the mechanism of the RB5 removal
using Fe/Pd was discussed and the evidences confirmed that the RB5 dye molecules were reduced
to some smaller aromatic compounds via cleavage of azo bonds.
References
[1] G. Crini, Bioresour. Technol. 97 (2006) 1061-1085.
[2] E. Forgacs, T. Cserháti, G. Oros, Environ. Int. 30 (2004) 953-971.
[3] W.J. Epolito, H. Yang, L.A. Bottomley, S.G. Pavlostathis, J. Hazard. Mater. 160 (2008) 594600.
[4] S. Chatterjee, S.-R. Lim, S.H. Woo, Chem. Eng. J. 160 (2010) 27-32.
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Effect of Carbon monoxide gas adsorption on the interior and exterior
surfaces of the Armchair Nanotubes using Density-Functional Theory
M. Dehestani
* ,a
, E. Mirzaie b
a)Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran ([email protected])
b) Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran
([email protected])
Abstract
The CO molecule adsorption on the inside and outside of (5,5) and (7,7) single-walled carbon
nanotubes (SWCNTs) was investigated using density functional theory. The adsorption energies,
equilibrium distances, HOMO-LUMOenergy gaps and chemical potential were studied. The results
show that after CO adsorption, electrical conductivity of the armchair nanotubes does not change.
Keywords: Adsorption energy, Chemical potential, Nanotube, CO molecule.
Introduction
The adsorption of CO molecule on the inner and outer surfaces ofthe SWCNTs have studied by
quantum chemistry calculations at the B3LYP/6-311G(d, p) level of theory. We examined a number
adsorbate orientations as well as different adsorption sites on nanotubes. The ab initio energies for
the CO adsorbed on (5,5) and (7,7) SWCNTs were computed for a total of about 250 points by
changing the tube-CO distance (R) from 1.5 Å to 8.5 Å at a step of 0.2 Å and angles from θ=0° to
θ =180° in a step of 45°. Ɵ is defined as the angle between C of nanotube, O and C of Carbon
monoxide. The length of tubes and the C-C average bond length are 10 Å and 1.42 Å, respectively.
These calculations have been performed to identify low-energy conformations of CO-SWCNT
complexes. It has been found that CO adsorption from O head is more favorable that C one [1].
Equilibrium Tube-CO distance (Re), adsorption energy (Ead), energy gap and chemical potential (µ)
are given in Table 1 for exterior and interior surfaces.
Conclusion
The data obtained at equilibrium tube-molecule distance show that equilibrium distance reduces
with increase in the angle from 0° to 135°. But the angle of 180°, due to exposure O atom in front
of the C atom of the nanotubes, repulsion increases and the equilibrium distance decreases.
1028
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In interior surface, since that all of atoms are carbon, so by increasing distance of atom O from C of
nanotube, duo to orientation of the CO molecule, equilibrium distances decreases with increasing
angle up to 180°.
A comparison between the energies gap obtained for the outside and inside of the tubes indicates
that the electrical conductivity of the armchair nanotubes does not change.
References
[1] J.L. Paredes, F. Suarez-Garcia, S. Villar-Rodil, A. Martinez-Alonso, J.M.D. Tascon, E.J.
Bottani, N2 physisorption on carbon nanotubes: computer simulation and experimental results, J.
Phys. Chem. B 107 (2003) 8905-8916.
Table1. Equilibrium distance, adsorption energy, energy gap and chemical potential forexterior and interiorsurfaces.
SWCNT
Ɵ
Re
Ead
Energy gap
(deg)
(Å)
(eV)
(eV)
(5,5) out
0
6.1
0.1037
1.5170
3.6959
(5,5) out
45
5
0.0129
1.5167
3.7029
(5,5) out
90
4.3
0.0017
1.5173
3.7140
(5,5) out
135
4.1
0.0017
1.5170
3.7104
(5,5) out
180
4.5
0.0038
1.5178
3.7048
(7,7) out
0
7.8
0.0025
2.4146
3.7774
(7,7) out
45
5
0.0151
2.4046
3.7759
(7,7) out
90
4.2
0.0111
2.4049
3.7823
(7,7) out
135
3.7
0.0196
2.4046
3.7800
(7,7) out
180
(5,5) in
0
3.2
8.9169
1.4960
3.6422
(5,5) in
45
3.1
9.5950
1.4149
3.6025
(5,5) in
90
2.9
9.5788
1.3573
3.7219
(5,5) in
135
2.5
8.9512
1.4057
3.7222
(5,5) in
180
2.4
8.7876
1.5148
3.6910
(7,7) in
0
4.7
1.5207
2.4139
3.7876
(7,7) in
45
4.5
1.0598
2.4033
3.7842
(7,7) in
90
4.2
0.8801
2.3995
3.7859
(7,7) in
135
3.7
1.3487
2.4065
3.7853
(7,7) in
180
3.5
1.5243
2.4120
3.7878
(n,m)
4.2
0.0088
2.4049
1029
µ(eV)
3.7763
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Conference
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Synthesis and magnetic properties of electrodeposited (Co 1-x Sn x )/Cu
multilayer nanowires
A.A. Rafati * a , M. najafi b , M. hamehveisi a
a
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali sina University, Hamedan, Iran
([email protected])
Keywords: AAO, Magnetic, multilayer nanowires, electrodeposition, Co1‐xSnx/Cu.
Introduction
Ferromagnetic nanowires synthsized by various methods, [1-2] Highly ordered nanowires with
multilayer of Co1-xSnx/Cu Have been successfully prepared by pulsed chemical electrodeposition
into nanoporous alumina membrane. The diameters of wires can be easily controlled by pore size of
alumina. The micrographs and crystal structurs of nanowires hve been characterized by
transmission electron microscopy TEM and SEM. The effect of off-time between pulses and Cu
concentrations on the magnetic properties, crystalline structure and weight percentage of Co1xSnx/Cu
multilayer nanowire have been studied by altermating gradient force magnetometer
(AGFM). [3]
Experimental methods
The Anodic aluminum oxide(AAO) was prepared by a two step anodizing process.
Al foil was first electropolished in ethanol/perchloric acid mixed solution at room temperature for 7
min. after electropolishing, the Al foil was anodized in 0.3 M sulfuric acid at 4°C for 7 (dc current).
To remove the oxide layer, the anodized foils were immersed into a mixed solution of H2CrO4 and
H3PO4. The foils were re-anodized for 24 h under the same conditions as the first step. The layer of
Au film was sputtered into on side through template, then remained Al and barrier layer on bottom
of AAO template dissolved. Co1-xSnx/Cu multilayer nanowire had been electrodeposited by DCpulse into AAO template. After the nanowires were formed the magnetic properties were studied by
AGFM.
Figures shows SEM and AFM images of AAO anodized after one-step anodizing.
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Magnetic properties of Co1-xSnx/Cu multilayer nanowire studied by altermating gradient force
magnetometer (AGFM). The coercivity increases with the deposition time when magnetic fieled
parallel to the nanowires , but remain unchanged when field perpendicular to the nanowires.
Conclusions
The Co1-xSnx/Cu multilayer nanowire have been fabricated into the AAO template by pulse
electrodeposition technique.
This caused the unique high coercivity and squareness, which are beneficial for future application
of magnetic storage.
References
[1]. Onous, t.; asahi, t.; kuramochi, K. Applied. Phy., 2002, 92, 4545.
[2]. Hamrakulov, B.; kim, i.; lee, m. g.; park, B. h.; trans. Nonferrous met. Soc. China., 2009, 19,
83-87.
[3]. Zhenxing, s.; yujuan, x.; suwei, y.; honzhi, w.; weiguo, z,; zhiyuan, t.; materials letters.,
2011,65, 1562-1564.
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DFT study of effects of Ga-doped on (8, 0), (10, 0), (12, 0) zigzag model
of BPNTs
M. Rezaei - Sameti*, S. Darabi , M. Farahani Farvazi, A. Khishvand
Department of Physical Chemistry, Faculty of Science, Malayer University, Malayer, 65174, Iran
[email protected]
Key word: Boron phosphide nanotube, NMR, DFT, Ga-doped
Abstract
After discovery of carbon nanotube (CNT) by Iijima [1], numerous researches have been focused to
investigate the properties and applications of new nanotubes that consist of groups III and V of
elements [2, 3]. Moreover, the new materials could be considered as promising candidates for future
electronics and optoelectronics applications because they are viewed as always wide gap
semiconductors [3]. To this time, the stable tubular structures of the counterparts of groups III and
V have been reported by either computations or experiments. In a recent work, we have studied the
structural and electrical properties of boron phosphide nanotube (BPNT), with different tubular
diameters and the effect of Ga-doped in spite of boron atoms on the structures’ parameters NMR,
HOMO, LUMO orbital properties [4-6]. For this aims we consider (8, 0), (10, 0) and (12, 0) zigzag
models of BPNTs by using DFT methods and B3LYP level of theory and 6- 31G (d) base set.
Computational methods
The structural and electrical properties of (8, 0), (10, 0) and (12, 0) zigzag models of undoped and
Ga-doped of BPNTs (see Figs.1) are optimized. After optimizing all consider structures of
nanotubes, we calculate the chemical shielding (CS) tensors at the sites of 11B, 31P nuclei based on
the gauge included atomic orbital (GIAO) approach and same level of theory. The calculated CS
tensors in principal axes system (PAS) (  33   22   11 ) are converted to measurable NMR
parameters, chemical shielding isotropic (CSI) and chemical shielding anisotropic (CSA) by using
equations (1) and (2), respectively.
1
CSI ( ppm)  ( 11   22   33 )
3
CSA( ppm )   33  ( 22   33 ) / 2
(1)
(2)
Results discussions
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The optimized results revealed similar bond lengths for equivalent positions in the three forms of
BPNTs. By doping Ga the bond length of neighbor atoms is increased and for P doping is decreased
and the gap energy of (HOMO-LUMO),∆
, is significantly increased. The CSI
values for 9B sites neighbor with doping Ga atoms are slightly decreased, on the other hand for 31P
sites neighbor are significantly increased due to lone pair of electrons in valence shell of phosphor
and more electronegative of it. The result show the value of CSA of BPGaNTs model at the P82 site
is smallest.
Fig.1 3D structures of (8.0), (10,0), (12,0) zigzag models of BPNTs.
References
[1] S. Iijima, Nature 354 (1991) 56.
[2] J. Cheng , R. Ding ,Y. Liu, Z. Ding , L. Zhang, Comput. Mater. Sci. 40 (2007)341–344
[3] H. R. Liu, H. Xiang, X. G. Gong, J. Chem. Phys. 135 ( 2011) 214702
[4] M. Rezaei-Sameti, Physica E 44 (2012) 1770–1775
[5] M. Rezaei-Sameti Physica B 407 (2012) 3717–3721
[6] M. Rezaei-Sameti, Physica B 407 (2012) 22–26
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Conference
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Synthesis and magnetic properties of electrodeposition (Co 1-x Cr x )/Cu
multilayer nanowires by pulse deposition
A.A Rafati * a , M. Najafi b , P. Assari
a
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali sina University, Hamedan, Iran
([email protected])
b
Deprtment of Materials Engineering, Hamedan University of Technology(HUT),Hamedan, Iran
Keywords:multilayer nanowire , magnetic, electrodeposition, (AAO) template.
Introduction
Magnetic nanowires have been widely used in fundamentals scientific issues such as magnetic
intractions, magnetic riversal and nano acale magnetic structures.[1-2] there are many different
methods to prepare nanowires. Among these, electrodeposition into an aluminum oxide template is
a simple and econmical technique. In this work The ordered anodic aluminum oxid (AAO) template
were synthesis via two step anodization process then AAO templates prepared to pulse
electrodepositionof nanowires. The ordered Co1-xCrx/Cu multilayer nanowires embedded in (AAO)
template have beeb fabricated by pulse electrodeposition method.
The highly ordered anodic aluminum (AAO) template had been prepared by two step anodization
process. High purity Al sheets were and ultrasonically degreased in methanol. The electropolished
Al foil are anodized using H2SO4elctrolyte at 25V. These AAO templates are dissolved in a mixed
solution of H2CrO4 and H3PO4. The remained aluminum are anodized in the same condition of the
first anodizationfor 24H .The layer of Au evaporated on top side of thetemplates then dissolved Al
by mixed solution of CuCl2 and HCl then barrier layer of AAO template dissolved by H3PO4.After
that
Co1-xCrx/Cu multilayer nanowire
had been electrodeposited by pulse into AAO template in
different times of pulses. After the nanowires were formed the magnetic properties were studied by
AGFM.
Figure1 shows SEM images of AAO template prepared by two anodizing process.
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Magnetic properties of Co1-xCrx/Cu multilayer nanowire studied by altermating gradient force
magnetometer (AGFM). The coercivity and thickness of each layer of nano wire depend on the
time of pulse during deposition .
Fig 1:SEM image of AAO template prepared by two anodizing process.
Conclusions
We have successfully synthesized Co1-xCrx/Cu multilayer nanowires in AAO template by pulse
electrodeposition. Different times of pulses in electrodeposition of nanowires had showed different
magnetization curves of (Co1-xCrx/Cu).
References
[1]. Sellmyer, d. j.; zheng, m.; skomski, r. j. phys. Condens. Matter. (2001), 13, R433.
[2]. Sun, l.; hao, y.; chien, c. l.; searson, p. c. j. res.dev. (2005). 49. 79.
1035
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Conference
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Metamaterial contains Au–Ag nanoalloy
A . Rostampoor a * , M.Nemati b *
a
Department of Physics,University of Qom,Qom, Iran
([email protected])
b
Department of Chemistry, Arak Branch, Islamic Azad University,Arak, Iran
([email protected])
Key words:Effective refractive index, Au–Ag nanoalloy, Metamaterials, Mie's theory
Introduction
In materials science, the range of properties of metallic systems can be greatly extended by taking
mixtures of elements to generate intermetallic compounds and alloys. One of the major reasons for
interest in alloy nanoparticles is the fact that their chemical and physical properties may be tuned by
varying the composition and atomic ordering as well as the size of the clusters[1]. In recent years,
metamaterials have been studied because of attractive properties such as negative refractive index in
especial incident wavelength[2]. On the other hand, scattering and absorption of light by
nanostructures is one of the physicists & chemists motivations. Mie could propose exact solution
for light scattering of spherical nanoparticles by solving of Maxwell's equations in 1908[3].In this
work, we suggest that for special wavelength and nanoholes size, the effective refractive index
shows negative value in Mie's theory and hence it could be considered as metamaterials.
Material and methods
Nanoalloys can be generated in a variety of media, such as cluster beams, colloidal solutions,
immobilized on surfaces, or inside pores. In this work we employed Mie's theory for nanoparticles
in
→ 0 regime, where ϵ is electric permittivity of medium. Moreover, we used Drude–
Sommerfeld model for effective electric permittivity(
(
). when
and
) and effective magnetic permeability
have negative values simultaneously, negative refractive index is
achieved[4]. One of the most important parameters in this alloy, the alloy percentage (X) that
represents the percentage contribution of gold and silver alloy is desired.Finally, in this research,
represents the effective refractive index profile for Au-Ag nanoalloy surrounding medium with
implanted spherical identical nanoholes as a function of the holes radius δ[5].
Result and discussions
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Refractive index depends on filling factor (f),incident wavelength () and radius of nanoparticles
and nanoholes (δ)[4]. In this paper, the parameter X is equal to 50 and filling factor is f= 0.1 .
Negative refractive indices were observed in follow figure.
Fig : effective refractive index of Au-Ag nanoalloy surrounding medium with implanted spherical identical nanoholes
for diverse holes radius and incident wavelength.
Conclusion
The properties of alloy nanoparticles can be very different from the properties of the component
monometallic nanoparticles. Generally, metmaterials are applicable in constructing optical
instruments such as super lenses due to high resolving power.Therefore, this study could be helpful
for experimentalists to design new super-lens by using of metal nanoparticles.
References
[1] R. Ferrando, Nanoalloys: From Theory to Applications of Alloy Clusters and Nanoparticles,
Chem. Rev. Vol 108, Number 3 (2006).
[2]S .Anantha Ramakrishna, T.M .Grzegorczyk . Physics and Applications of Negative Refractive
Index Materials, Taylor & Francis Group, LLC(2009).
[3]Gouesbet, G., Gréhan, G .Generalized Lorenz-Mie Theories, Springer-Verlag (2011).
[4]M.Tagviashvili, Phys .Rev.A. 81, 045802 (2010).
[5]Johnson.P.B. Christy, R.W .Phys.Rev .B, 6, 4370-4379(1972).
1037
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Conference
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Effective refractive index of metamaterial fabricated from nanosilvers
A . Rostampoor a *
a
Department of Physics,University of Qom,Qom, Iran
([email protected]) Key words:Effective refractive index, Nanosilver, Mie's theory, Metamaterial
Introduction
Much experimental and theoretical efforts has been recently devoted to the study of a new type of
metamaterials that have simultaneously negative electric permittivity ε and magnetic permeability μ
and are thus termed as negative refractive-index materials (NIM), or left-handed materials[1]. Over
thirty years ago, Veselago [2] predicted theoretically that electromagnetic waves propagating in
isotropic NIM’s possess several peculiar characteristics, including anomalous refraction, reversal of
both the Doppler shift and the Cerenkov radiation, and reversal of radiation pressure to radiation
tension[3]. On the other hand, scattering and absorption of light by nanostructures is one of the
physicists & chemists motivations.Mie could propose exact solution for light scattering of spherical
nanoparticles by solving of Maxwell's equations in 1908 [3].Mie's theory was represented for
isotropic, homogeneous and spherical particles intoisotropic,homogeneous and non-absorbing
surrounding mediums [4].In this work, we suggest that for special wavelength and nanoholes size,
the effective refractive index shows negative value in Mie's theory and hence it could be considered
as meta-materials.
Material and methods
In this work we employed Mie's theory for calculation of effective refractive index of nanosilvers in
→ 0 regime, where ϵ is electric permittivity of medium. Moreover, we used Drude–Sommerfeld
model for effective electric permittivity(
) and effective magnetic permeability (
) [1].
Finally, in this research,represents the effective refractive index profile for nanosilver medium with
implanted spherical identical nanoholes as a function of the holes radius δ [5].
Result and discussions
Refractive index depends on filling factor (f),incident wavelength () and radius of nanoparticles
and nanoholes (δ)[1].The nanohole’s refractive index is equal to
f= 0.1. Negative refractive indices were observed in follow figure.
1038
= 1 and system filling factor is
‫ھ‬
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Conference
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Fig 1: effective electric permittivity and effective magnetic permeability of nanosilver medium with implanted
spherical identical nanoholes for diverse holes radius.
Fig 2: effective refractive index of nanosilver medium with implanted spherical identical nanoholes for diverse holes
radius and incident wavelength.
Conclusion
In summary, we have studied the influence of fabrication parameters such as radius of nanoholes on
the effective refractive index by using of Mie theory and Drude–Sommerfeld model. An unusual
behavior is found at 0, which leads, in negative value for effective electric and magnetic
permeability, simultaneously and hence effective refractive index which clearly shows that in
especial condition medium contains metal nanoparticles should be consider as metamaterials.
References
[1]M.Tagviashvili, Phys .Rev.A. 81, 045802 (2010) .
[2] V.G. Veselago Sov. Phys. Usp. 10, 509 (1968).
[3]S .Anantha Ramakrishna, T.M .Grzegorczyk . Physics and Applications of Negative Refractive Index Materials,
Taylor & Francis Group, LLC(2009).
[4]Bohren, C.F., Huffman, D.R .Absorption & Scattering of Light by Small Particles, John Wiley & Sons.Inc. (1983).
[5]Johnson.P.B ., Christy, R.W .Phys.Rev .B, 6, 4370-4379(1972).
1039
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Conference
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On the calculation of binding energy of a trapped molecule
in a nanochannel via non-local potentials
Ali Maghari * . Maryam Mansoori Kermani
School of chemistry, College of Science, University of Tehran, Iran
Keywords: nanochannel, Lippmann-schwinger equation, nonlocal potential, binding energy
Introduction
As it known, the fluids confined in nanochannels play an important role in all of the fields in
science and technology. Many theoretical and experimental studies have been done for investigation
the physical and thermophysical behaviors of confined fluids in nano scale but their properties have
been not completely realized. It is said that the differences between the behaviors of fluids in this
scale and the macroscopic scale, that are explained with Navior-Stokes equation, are related to the
competition between the interaction of molecules of fluids and molecules of fluids and surface. This
competition creates the nonuniform density profile and the changes in equilibrium properties and
phase diagram for fluid.
In this work, a nanochannel with two parallel surfaces has been considered that one fluid flows
inside the channel as it has been illustrated in Fig.1. When the one molecule of fluid passes the
surface, after incidence with it, there are two possibilities for the next behavior of this molecule.
Either a molecule of a confined fluid scatters or traps on the one of the crevices of surface. The
probability for these two processes, i.e. scattering or adsorbing, as well as the binding energy of
adsorption of a molecule in a hole are calculated.
Fig.1 the geometry of nanochannel
Theoretical approach
Consider a fluid confined in a nanochannel. The relative Hamiltonian can be given by
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Conference
w
p2  2 2
Hˆ 
  r  Veff   U ( rk ) 2 2
k 1
‫ه ﯽ‬
N
(1)
where  is reduced mass and  the confining frequency. We assume that the interaction between
the considered molecule with other fluid molecules can be replaced by an effective mean field term,
which represented by Veff . Moreover, the interaction potential between the fluid molecule and
channel walls (holes) is considered as non-local separable potential (NLSP). The NLSP is used
more widely in the areas of condensed matter, since the multi-particle problems can be formulated
in terms of two-body NLSPs. One example for application of this potential was brought in ref. [2].
The general form of the NLSP is the following
n
Vˆ    i ;  vi( ) ;  i
(2)
i 1 
wheren is the rank of the potential operator Vˆ , vi() is the attractive (or repulsive) coupling strength
and  i ;  is state of the system with angular momentum quantum number  , which is a real
number in the unitary case. The momentum representation of such potential is
n
Vˆ  p, p  p Vˆ p   vi( )  i(  )  p  i( )*  p 
 ( pp  )
(3)
i 1 
The transition of the fluid molecule from initial state a, which we assume a free particle in an
effective interaction field, to the final state b, i.e. the molecule in a channel with walls potential, can
be describe by using the channel transition operator via Lippmann-Shwinger equation
Tâ  b  Vâ  Vˆb
1 ˆ
Va
z  Hˆ
(4)
where z  E  i is the complex-energy parameter.
In this work, a Yamaguchi type form factor  i(  ) ( p ) , appeared in Eq. (3), is selected, since it has a
Yukawa form in coordinate representation. This model potential is simply represented a longranged potential, such as Coulomb potential, or a short-ranged potential, such as van der Waals or
Lennard-Jones potentials. The generalized Yamaguchi type form factor is given by
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Conference
 i( ) ( p)
2
2  1
1  2 ! (2  1) ai , 
 3/ 4 

  (  1 / 2) 
1/ 2
(ai2,
‫ه ﯽ‬
p
 p 2 ) 1
(5)
where n  the Gamma function and the attractive (or repulsive) inverse range ai , plays the role of
scale factor. We now turn to study the analytical properties of the transition matrix in the complex
q-plane. The transition matrix explicitly shows the contributions from the bound states, resonances
and distinct singularities in the complex plane and plays an important role in calculation the
statistical mechanical properties of confined fluid.
The Yamaguchi’s NLSP provides excellent results over the whole range of channel sizes, from
strong confinement regime (the channel diameter is smaller than cut-off potential) to a weak
confinement interaction (the channel diameter is larger than cut-off potential). Finally, by using the
Lippmann-Schwinger equation, we calculate the binding energy for the trapped molecule of fluid
on the surface. The importance of our model is that it is quietly general formulation, not for a
special material of fluid or solid surface in nanochannel.
References
[1] Yamaguchi, Y., Phys. Rev.95 (1954) 1628.
[2] Faddeev, L.D., Sov. Phys.-JETP12 (1961) 1014.
[3] Krotscheck, E., Apaja, V., Eur. Phys. J. Special Topics 141 (2007) 83.
[4] López, S., Dom´ınguez-Adame,F., Semicond. Sci. Technol. 17(2002) 227
[5] Maghari, A., Tahmasbi, N., J. Phys. A: Math. Gen.38 (2005) 4469.
[6] Maghari, A., Dargahi, M., J. Phys. A: Math. Theor.41 (2008) 275306.
[7] Maghari, A., Tahmasbi, N., PhysicaA382 (2007) 537.
[8] Maghari, A., Dargahi, M., J. Stat. Mech. (2008) P10007.
1042
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Conference
‫ه ﯽ‬
Investigation a nano-model including the intermolecular Lippincott
potential combined with Casimir and electrostatic forces with
fractional damping
Maryam Mansoori Kermani * , Maryam Dehestani
Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran
E-mail:[email protected]
Introduction
Recently, the Nanoelectromechanical systems (NEMS) have turned into the critical research topic.
In NEMS, there are the parallel plates with some effective forces.As it known, The Casmir force is
an attractive force that can be between a sphere and a plate that both are perfectly conducting and
having smooth surfaces. This force was first introduced by Casimir [1] and it has many applications
in nanotechnology and NEMS system. The investigation of the motion of movable components
produces some nonlinear equations.One method for solving the nonlinear equations in many
applied sciences is the Adomian decomposition method. It was first introduced by G. Adomian and
is a non-numerical and semi-analytical method for both ordinary and partial differential equations
[2].
We examine the anharmonic vibrations of a nano-sized oscillatormodel with fractional damping.
Our approach is investigation of intermolecular potential on the equation of motion in the nano
devices. We consider a force derived from the Lippincott potential [3] and also Casimir and
electrostatic forces. The solution is found using the Adomian decomposition method. Our model is
a one-dimensional oscillator consisting of a sphere with radius R and mass m, which is suspended
by means of vertical elastic wire which produces a force originating in particular potential, on a
horizontal conducting surface [4]. The Casimir and electrostatic forces are present between the
sphere and conducting. The equilibrium distance between centre of sphere and surface is d e >>R.
The linear fractional derivatives operator can be written as:
t

1
dn
(t  y ) n 1 f ( y )dy

n
 (n   ) dt a

Dt ,a x(t )  
n
d
 dt n f (t )
n  1   n
(1)
 n
where n is an integer. The more information has been discussed in [5].
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Conclusions
This method is the new approach for using the intermolecular potential in a model for nano devices
and can be applied for other potential for oscillations in the model. This method has the benefit to
reduce the anharmonic oscillator to a driven quantum oscillator, and the above formalism is suitable
to investigate the higher vibrational states of oscillator.Our method can be applied in the higher
powers of exponential expansion. This work could be evaluated on a three dimensional model.
We obtained the equation of motion for µ=1 (µ is a fractional number) as:
x L (t ) 
f 0
Q
cos[ t ] 
M Z
3
2 3
m
m de
3
Q    c R 360
that λ is a damping constant ,
(2)
c,
and
are the velocity of light and the Planck
constant/2π, respectively.
M 
(3)

t 2 5 t 2 Ae3 3 t 2 Ae2 3 t 2 Ae 30 Ae2 f 0 sin( t ) 12 Ae f 0 sin( t ) 3 f 0 sin( t )






2
de3
de2
2 de
m  4 d e3
m  4 d e2
m 4 de
15 Ae f 02 t 2 15 Ae f 02 cos(2 t )
3 f 02 t 2
3 f 2 cos(2 t ) 15 f 03 sin( t ) 5 f 03 sin(3 t )


 0 2 6 2 

2
4 3
2
6 3
2
4 2
2 m  de
4 m  de
2 m  de
4 m  de
2 m3  8 d e3
18 m3  8 d e3
For any applied potential such as Rydberg, Varshni and Murrel-Mottram potentials, M is the same
term but the Z is deferent and including the very large terms for the Lippincott potential.
References
[1] H. BG. Casimir, On the attraction between two perfectly conducting plates, Proc. K. Ned.
Aaa
Akad. Wet. 51 (1948) 793-796.
[2] A. M. Wazwaz, A comparison between Adomian decomposition method and Taylor series
method in the series solution, Appl. Math. Comput. 97 (1998) 37-44.
[3] E. R. Lippincott, D. Steele, P. Caldwell, General relation between potential energy and
aaaainternucleardistance for diatomic molecules. III. Excited states, J. Chem. Phys. 35 (1961)
aaaa123-141.
[4] M. Mansoori Kermani, M. Dehestani, Solving the nonlinear equations for one-dimensional
nano-sized model including Rydberg and Varshni potentials and Casimir force using the
decomposition method, Appl. Math. Modeling 37 (2013) 3399-3406.
[5] B. Oldham, Spanier J. Fractional calculus. San Diego: Academic Press; 1974.
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A survey upon Measuring the Thermal Effusivity of
Tetraoxoosmium Nanofluid by Applying Photoacoustic Method
Kourosh Motevalli a* , Zahra Yaghoubi b
a
Applied chemistry department, faculty of sciences, Islamic Azad university, south Tehran branch, Tehran, Iran
b
Industrial Engineering faculty, Islamic Azad university, south Tehran branch, Tehran, Iran
It is known that Metal oxide NPs dispersion in liquids are of fundamental as well as technological
interest pertaining to nanofluidical and other applications including antibacterial medical treatment
and thermal management systems because of transport property enhancement .Photoacoustic (PA)
sensor was designed and developed to evaluate thermal effusivity of tetraoxoosmium nanofluid. The
PA sensor is based on open cell mode (OPC) to measure acoustic signals from low concentration of
nanoparticulate suspensions in ethylene glycol (EG). Spherical tetraoxoosmium nanoparticles (NPs)
were obtained by chemical precipitation method in powder form. The obtained NPs were stabilized
by acetylacetone (acac) in EG. Thermal conductivity estimation was carried out with the help of
transient hot wire method. The developed PA sensor was calibrated by measuring thermal effusivity
of standard samples. The acoustic signals of the PA experiments have been analyzed with a simple
Rosencwaig-Gersho theoretical model.
Keywords: Thermal, antibacterial, tetraoxoosmium, sensor, PA, NPs
Introduction
Recently, there has been significant interest in studying different thermophysical properties of
Nanofluids such asthermal conductivity, diffusivity, andeffusivity [1,2]. The two dynamic thermal
parameters, thatis, thermal diffusivity α and effusivity ε is connected with other thermal parameters,
thatis, thermal conductivity k and volume tricspecificheatc p by α= k/ρc p andε=kρc p where ρ isthe
density of sample. The thermal effusivity measuresessentially the thermal impedance of sample or
the ability of sample to exchange heat with environment[3]. To completely characterize the
nanofluid out of three, two parameters are required. Reported studies onthermal properties of
nanofluids are mostly based upon the thermal conductivity measurement. Exact determination of
thermal effusivity of such nanoparticulated is persed phase would be complementary to the thermal
conductivity obtained by hot wiremethod. Photoacousticmethods are known to be useful tools for
investigation of thermal parameters for gases, liquids, thin films, and powdermaterials[4]. There has
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been considerabl eamount of work base don experimental techniques related to PA spectroscopy [5].
For NPs dispersionsat very low concentrations or solid particle loading the sample were effectively
treatedastransparent one,and Rosencwaig- Gersho(RG) theorycould be applied[6].Thes inglemost
important parameter that characterizes the PA systemis pressurevariations, induced by samples
surface temperature which are detected by amicrophone coupled to PA cell [7]. To overcome this
problem, open methods hasbeen introduced. To measure the PA signal of liquid sample, OPC
technique has been proved to be a powerful tool bot hin term soft helowcostandeasy data analysis.
The application of OPC to higher densecolloidssuspension is limited due to unavailability of theory.
In this research, the thermal effusivity and conductivity were investigated for EG based
TetraoxoosmiumNFs.
2.Experimental
In a typical open cell PA experiment, the excitation beam is used to generate the thermal waves in
the sample which are transfer redtomicrophoneasanacoustic signal via Al foil coupled to sample as
well as gas beneath. A beam of mono chromatic light from helium neon (He-Ne632nm,
(PCB130D20) consisting of abuilt-inpreamp lifier.Out put signals of PA transducer were again
amplified with signal conditionerandacquired with the help of lockin amplifier (SR7265).Also, a
(10mW) laser is used asan excitation source. The light beam was focused with the help of lensand
passed through chopper. Also, Pressure modulation occurs with in the PA cell. Acoustic waves in
duced by light were detected by amicro phone transducer.
The preparedTetraoxoosmium NPs have been characterized by scanning electron microscopy (SEM)
(Figure1). The test sample was prepared by placing drop of colloid also lutiononglass substrate and
heat edslightlyto evaporateEG.TheSEM observationsshowthattheparticlesareorganizedinachainlikestructure.Evidenceoftheoccurrenceofaggregatesin the absenceof
alsobydirect
visualinspection(chainlengthupto3mmandwidthup
magnetic fieldwasfound
to
500nm)
.
Thisaggregatehasbeenformed under self-assemblyprocess. Also, the experimentsshow thatdynamic
light
scatteringanalysishavingparticlesizearound200nmwith
ofTetraoxoosmiumNPsproduceschange
inthermal
ascanbeseenfromenhancementofPA signalandeffusivity.
Conclusions
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propertiesofEG
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Thedescribed OPC technique can be effectively applied to evaluation of thermal properties of dilute
NPs
suspensions.
Results
show
that
PA
signal
changes
significantly
with
inclusionofTetraoxoosmiumNPsin EG.
(b)
Figure1:SEM picturesofOsO4NPs.
References
[1]J. A. Balderas-Lopez,“Photoacousticmethodologyto measure thermalandopticalpropertiesofdyesolutions,”Review of
ScientificInstruments,vol.77,no.8,ArticleID086104,2006.
[2]J.A. Balderas-LopezandA.Mandelis,“Self-consistentphotothermaltechniques:applicationfor measuring thermal
diffusivityinvegetableoils,”ReviewofScientificInstruments, vol.74,no.1,part2,pp.700–702,2003.
[3]A.K.Shrotriya,L.S.Verma,R.Singh,andD.R.Chaudhary, “Predictionoftheheatstoragecoefficient ofathree-phase
system,”JournalofPhysics,vol.24,no.9,pp.1527–1532,1991.
[4]X.Wang,H.Hu,andX.Xu,“Photo-acousticmeasurementof thermalconductivityofthinfilmsand bulkmaterials,”Journal
ofHeatTransfer,vol.123,no.1,pp.138–144,2001.
[5]L.S.Verma,A.K.Shrotriya,U.Singh, andD.R.Chaudhary,“Heatstoragecoefficient.animportantthermophysical
parameter and itsexperimental determination,” Journal of Physics,vol.23,no.11,pp.1405–1410,1990.
[6]T.M.Coelho,E.C.Vidotti,M.C.Rollembergetal.,“Photoacousticspectroscopyasa toolfordeterminationoffooddyes:
comparisonwithfirstderivativespectrophotometry,”Talanta, vol.81,no.1-2,pp.202–207,2010.
[7]E.Sehn,K.C. Silva,V.S.Retuci et al.,“Photoacoustic spectroscopytoevaluatethepenetration ofsunscreensinto
humanskininvivo:astatistictreatment,”ReviewofScientific Instruments,vol.74,no.1,part2,pp.758–760,
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Kinetic and equilibrium studies of the removal of dye pollutants by
novel silver/ordered mesoporous alumina nanocomposite
BaharehYahyaei a , SaeidAzizian* ,a
a
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
([email protected])
Keywords:Silver/Ordered Mesoporous Alumina, Rapid Adsorption, Adsorption Kinetics,
Adsorption Isotherms.
Introduction
One of the serious problems in the present century is environmental pollution by industries.
Nanocomposites are multiphase solid materials that have been used as adsorbent of pollutants such
as dyes, pesticides, anions and etc. in the last decades. Various methods such as ozonation [1],
flocculation [2], adsorption [3] and etc. have been used to treat these waste waters. Among these
methods adsorption is the most effective and low cost method. In this study a novel nanocomposite,
silver/ordered mesoporous alumina (Ag/OMA) has been synthesized and used for removal of dyes
pollutants (methyl orange, bromothymol blue and reactive yellow) from aqueous solution.
Ag/OMA nanocomposite was synthesized by chemical method using aluminum iso-propoxide as
aluminum source, F127 triblock copolymer as a pore directing agent and ethanol as a solvent and
silver nanoparticles were prepared by photogeneration method [4]. Characterization of
Ag/OMAnanocomposite has been performed by TEM, BET and EDX techniques.
The kinetic and equilibrium studies show that the Ag/OMA nanocomposite can remove anionic dye
effectively from aqueous solution. The removal percentage of all dye pollutants is more than 25%
only after 30s. So the synthesized nanocomposite can impressively remove dye pollutants from
aqueous solution in short time.Pseudo first order (PFO), pseudo second order (PSO) and
Elovichrate equations have been used to analyze kinetic data.According to the correlation
coefficients the kinetic experimental data were best fitted with Elovich rate equation for all dye
pollutants on Ag/OMA nanocomposite.The maximum capacity of synthesized nanocomposite for
dye pollutants can be measured using equilibrium isotherms. Langmuir, Freundlich, LangmuirFreundlich and Redlich-Peterson isotherms have been used to analyze the experimental equilibrium
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data.According to the correlation coefficients the experimental equilibrium data are best fitted with
Langmuir-Freundlich isotherm.
Conclusions
Ag/OMA nanocomposite has ordered structure involves silver nanoparticles which endows
antibacterial property to the synthesized adsorbent. The adsorption of dye pollutants onto the
surface of Ag/OMA is much faster than the adsorption ontothe surface of activated carbons and
commercial alumina. Also the adsorption capacity of the Ag/OMA is comparable to activated
carbons. Therefore Ag/OMA nanocomposite can be effectively used to removal of the dye
pollutants from aqueous solutions.
References
[1]. Chen, J.; Zhu, L.; Chemosphere, 2006, 65, 1249–1255.
[2]. Guibal, E.; Roussy, J.; J. React. Funct.Polym, 2007, 67, 33–42.
[3]. Yahyaei, B.; Azizian, S.; Chem.Eng. J., 2012, 209, 589–596.
[4]. Yahyaei, B.; Azizian, S.; Spectrochim.Acta A, 2013, 101, 343–348.
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Application of Magnetite Nanohollow Spheres and their use as Drug
Carrier
A.A. Rafati*, S. Shirazi
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
([email protected])
Keywords:Magnetic Nanoparticle, Drug Carrier, Drug Release, Kinetic Study.
Introduction
Magnetic nanoparticles have been widely used for, magnetic resonance imaging hyperthermia
cancer treatment, and bioseparation [1-3]. Another possible and most promising application of
magnetic nanoparticles is in drug delivery as carriers of drug for site-specific delivery of drugs.
Ideally, they could bear on their surface or in their bulk a pharmaceutical drug that could be driven
to the target organ and released there [4].
Hollow magnetic/silica nanospheres have been synthesized in our previous work [5]. In the present
study the synthesized nanospheres have been used as drug carrier for propranolol, imipramine and
chlorpromazine. In vitro release studies of drugs have been performed after loading drugs into the
inner core and onto the surface of the nano spheres at pH = 7 and 9 and drug release kinetic process
was followed by UV-vis spectroscopy.
For loading drug on to the hollow magnetic/silica spheres, nanospheres and drugs were mixed in
aqueous media with the ratio of 1:4 wt%. After 24 h, obtained nanocarriers were separated by
centrifugation followed by washing with distillate water several times. In vitro release studies of
drugs, were followed by UV-vis spectroscopy. The effect of pH on drug release has also been
investigated.
Kinetic study shows drug release in pH = 7 followed Korsmeyer-Peppas model (equation 1) and in
pH = 9 followed Weibull model (equation 2).
C 
log  t   n log t  log k K  P
 C 

C  C 1  e k
W
t T  b
(1)

(2)
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Conclusions
The results show that the release of investigated drugs especially propranolol and imipramine have
been occurred slowly with nearly linear procedure at pH = 7. Since all investigated drugs have liver
metabolism and the liver media is neutral (pH = 7), these results are favorable. So that hollow
magnetic/silica spheres can be used as a proper carrier for propranolol, imipramine and
chlorpromazine and can be exploited in drug delivery applications.
References
[1]. Ma, H.; Zhuo, j.; Caruntu, D.; Yu, M. H.; Chen, J. F.; Zhou, W. L. Applied. Phy., 2008, 103,
07A320-323.
[2]. Yang, H. H.; Zhang, S. Q.; Chen, X. L.; Zhuang, Z. X.; Xu, J. G.; Wang, X. R.; Anal. Chem.,
2004, 76, 1316-1321.
[3]. Tada, M.; Kanemaru, T.; Hara, T.; Nakagawa, T.; Handa, H.; Abe, M.; J. Magn. Magn. Mater.,
2009, 321, 1414-1416.
[4]. Gupta, A. K.; Gupta, M.; Biomaterials, 2005, 26, 3995–4021.
[5]. Rafati, A. A.; Shirazi, S.; Proceeding of the 15th Iranian Physical Chemistry Conference,
University of Tehran, 2012, 2356-2358.
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Tungsten Oxide Nanocrystals and NO x Sensing Properties
M. Izadyar, A. Jamsaz
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
[email protected]
Keywords: Electrochemical potential; WO3nanocrystal; Adsorption; NOx; Quantum
computations
Introduction
Tungsten oxide (WO3) is a wide band gap semiconducting metal oxide [1]. It exhibits various
chemical properties which make it very promising for applications in electrochoromic displaying
[2] photocatalysis [3] and particularly in gas sensors [4]. WO3 plays a role as a sensitive layer for
detecting small quantities of NOx, NH3, O3, H2 and so on[5]. Density functional theory (DFT)
calculations are useful in studying the structural and electronic properties of oxide semiconductors.
Recently, there have been numerous theoretical studies on WO3, including DFT and Hatree-Fock
(HF) calculations [6].
Method
All the calculations have been carried out using the GAUSSIAN 09 package [7]. DFT methods of
the B3LYP and X3LYP in conjunction with LANL2DZ basis set have been utilized. In comparison,
X3LYP method predicted stronger physical adsorption relative to B3LYP method. In the present
work, it has been reported the results of our studies on the geometries, electronic structures,
adsorption energies, absolute hardness, electronic chemical potentials of W8O12H16 and W8O36H24
nanocrystals with the possible use of WO3 nanocrystals as a gas sensor particularly for NOx(x=1,2).
The interaction energy of the NOx molecules with different substrates has been computed in the
following manner according to equation 1:
ΔE= E(NOx@(WO3) –E((WO3))-E(NOx) equation 1
Natural bond orbital (NBO) and the electronic density of states (DOS) were also calculated in order
to analyze the electronic structure.
As a starting point we performed an ion position freezing for the cubic WO3 unit cell. Considering
the interaction energies, it has been suggested that W8O12H16 is the best candidate from the surfaces
analysis point of view. Theoretical data show that the NO adsorption energy is larger than NO2 by
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0.6eV. According to hardness analysis and electrochemical potentials it has been concluded that the
nano-crystalls band gap decreases (~0.01 eV) after adsorption, which is related to further
hybridization between 2p states of O and 5d states of W atoms of the crystals. Another important
result from the theoretical calculations is referred to the Fermi level of W8O36H24 nanocrystal which
is shifted by 0.014 eV toward high energy direction (from -3.913 to –3.899 eV). This is accordance
to the partial filling of conduction band and the increase of the conductivity resulting from the NO
adsorption. Finally, considering all data, it is revealed that the nanocrystalline structures of WO3 can
be used for detection of NO better than NO2.
Figure 1.Optimized structures of NO@ W8O36H24.
Conclusions
First principles calculations at the DFT level were used for the study of the structures of W8O12H16
and W8O36H24 crystals as a gas sensors for NOx(x=1,2). The geometries were optimized at the
B3LYP and X3LYP method.All the calculations have been carried out using the GAUSSIAN 09
package using LANL2DZ basis set.Considering the interaction energies, it has been suggested that
W8O12H16 is the best candidate from the surfaces analysis point of view.According to hardness
analysis and electrochemical potentials calculations, it has been concluded that the nano-crystalls
band gap decreases after adsorption.
References
[1] H.J. Zheng, X.D. Wang, Z.H. Gu, ActaPhys.Chim.Sin, 25 (2009) 1650.
[2] W.Z. Li, J. Li, X. Wang, S.J. Zhang, Q.Y. Chen. ActaPhys-Chim.Sin, 26 (2010) 2343.
[3] Y. Liu, S. Wang, T.Wang, Z.L. Xu, Catal 31(2010) 485.
[4] C.M. Ghimbeu, M. Lumbreras, M. Siadat, J.Schoonman, Mater. Sci. Semicond. Proc, 13 (2010)
[5] J. kong, N.R. Franklin, C. Zhou, M.G .Chapline, S. Peng, K.Cho, H. Dailt, Science 287(2000)
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[6] W.Fenggong, Di Valentin.Cristiana, P.Gianfranco, J.Phys. Chem 115 (2011) 8345.
[7] Gaussian 09, Revision A.02, Gaussian, Inc., Wallingford CT, 2009.
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DFT Study on the Interactions of NO-WO 3 Nano-Clusters
M. Izadyar*, A. Jamsaz
Department of Chemistry, Faculty of sciences, Ferdowsi University of Mashhad, Mashhad, Iran
Keywords: Adsorption, NO, Density of States (DOS), Density Functional Theory (DFT), Band
Gap
Introduction
Different materials such as SnO2, WO3, ZnO, MoO3, TiO2 and mixed oxides have been studied and
show promising applications for detecting gases such as NH3, O3, NOx, H2S, and SOx[1,2]. Among
various metal oxide semiconductors Tungsten trioxide exhibit various special properties, which
make it very promising for or applications in catalysis [3] and detection of toxic gases such as NOx,
H2S, and NH3 [4]. For WO3-based gas sensors, WO3 plays a role as a sensitive layer for detecting
small quantities of NOx and Such nano-scale assemblies can achieve high sensitivity and fast
response times [5]. In this work we have studied the chemical and physical interactions of adsorbed
NO on the cyclic (WO3)n (n=2-6) Nano-Clusters surfaces using the DFT method.
Method
First principles calculations at the DFT level have been used for the study of (WO3)n(n=2-6)
clusters. Tungsten oxide structures were generated in the vacuum and fully optimized using the
ultra-soft pseudo potential with exchange-correlation functional including B3LYP and X3LYP. All
the calculations have been carried out using the GAUSSIAN 09 package using LANL2DZ basis set
[6]. The interaction energy of NO molecule on five different substrates has been computed for the
two models (N-head or O-head of adsorption) in the following manner according to equation 1:
ΔE= E(NO@(WO3)n) –E((WO3)n)-E(NO)
equation 1
Cyclic clusters of WO3 were chosen as the starting point of the calculations, as presented in Figure
1.
n=2
n=3
n=4
n=5
n=6
Figure 1. Optimized structures of cyclic cluster of (WO3)n(n=2-6).
Different orientations of oxygen and nitrogen atoms of NO molecule on the nano-clusters were
completely investigated. Adsorption site of the adsorbent and intermolecular interaction between
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the surface and NO molecule will be different from the energy point of view, using various DFT
methods. In comparison, X3LYP method predicted stronger physical adsorption relative to B3LYP.
It was also found that the global stable structures are achieved with n=2 at the X3LYP/LANL2DZ
level. According to the theoretical data, the best adsorption site for NO is the N-head with
theadsorption energy of 0.685 eV. Computed bond orders of W-O bonds (0.45-0.48) for all
structures, suggest that the interaction between W and O atoms has weak covalent character in
addition to ionic bond. Mulliken population analysis confirms that the W atom has a positive
character, carries a charge of +1.6 e, while O atom has a negative charge,-0.6 [7]. From the values
of the negative character for O atom and the positive character for W atom, one can conclude that
W and O atoms do not exist as W6+ and O2- as in the bulk of WO3. Accordingly, there are
considerable orbital overlaps between W and O atoms. Back-donation of lone pair electrons of O
atoms to the vacant d orbitals of W atoms is the source of this covalent character for W-O bonds.
Density of states (DOS) spectrum analysis shows asymmetric nature, with respect to up and down
spin, which is typical for an open shell system. Considerable changes in the electronic states
spectrum can be seen after adsorption. It is evident that all energy states are pushed toward higher
energy side. As expected, s-orbitals which are deep buried inside, are least affected by the
interactions. The peaks which are corresponding to p-orbitals, near the Fermi level become little
broader.The value of band gap decreases after adsorption. Finally, the dependence of adsorption
energy on charge transfer and electronic chemical potential were investigated using Natural bond
orbital (NBO) method.
Conclusions
Ab initio calculations, using the density functional theory (DFT) with the X3LYP and B3LYP
hybrid functional were applied to study the NO adsorption on the (WO3)n nano-clusters. All the
calculations have been carried out using the GAUSSIAN 09 package using LANL2DZ basis set.
X3LYP method predicts stronger physical adsorption computed than B3LYP. NBO and the DOS
methods were also done in order to analyze the electronic structure which leads to shifting energy
bond towards low-energy region.
References:
[1] G. Korotcenkov, I. Blinov, M. Ivanov, J.R. Stetter, Sens. Actuat. B 120 (2007) 679.
[2] B. Timmer, W. Olthuis, A. Berg, Sens. Actuat. B 107 (2005) 666.
[3] I.N. Yakkovin, M. Gutowski, Surface Science 601(2007)1481.
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[4] C.G. Grandquist, Appl.Phys. A57 (1967)158.
[5] J. kong, N.R. Franklin, C. Zhou, M.G .Chapline, S. Peng, K.Cho, H. Dailt, Science 287(2000)
622.
[6] Gaussian 09, Revision A.02,Gaussian, Inc., Wallingford CT, ( 2009).
[7] E.D. Glendening, C.R. Landis, F. Weinhold, Wires Comput. Mol. Sci 2( 2012) 1.
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Preparation of ZnO Nanostructures by Thrmolysis of four coordinated
Zn(II) Complex
Akram Hosseinian * ,1 , Maryam Movahedi 2 , Azam Anaraki Firooz 3
1
Department of Engineering Science, College of Engineering, University of Tehran, P.O. Box 11365-4563 Tehran, Iran
2
Department of Chemistry, Payame Noor University, P.O. Box 19395-3697 Tehran, IRAN. 3
Dep. of chemistry, Faculty of science, Shahid Rajaee Teacher Training University, P.O. Box 167855-163 Tehran, Iran
(E-mail: [email protected])
Keywords: Nanostructure, ZnO, Thermolysis, Complex; four coordinated
Introduction
The development of metal oxide nanostructure has been intensively pursued because of their useful
applications in catalysis, energy storage, magnetic data storage, sensors and ferro fluids. ZnO has a
direct band gap of 3.3 eV at room temperature with a free excision binding energy of 60 meV which
is important among semiconductor materials for its unique properties, such as optical transparency,
electric conductivity, piezoelectricity, near-UV emission. ZnO nanostructures have been the subject
of intense interest due to their potential wide-ranging applications in a variety of fields such as
catalyst, photocatalyst, field effect transistors, resonators, short-wave optics, gas sensors,
antibacterial agent, solar cells optoelectronic devices and functional materials [1-3].
Materials and methods
To prepare of four coordinated [Zn(DADMBTZ)(ac)2] complex a proper amount of solution of
zinc(II) nitrate and ammonium acetate (0.1 M) in EtOH was placed in an ultrasonic bath, and into
this solution, a proper volume of DADMBTZ solution (0.1 M) was added in drops. The resulting
precipitate was filtered, subsequently washed with EtOH, and then dried.The obtained compound
was calcinated at 500°C under air for 1 h in an electric furnace alumina boat. The organic
components were combusted and ZnO nanostructure was produced.
Apparatus
Infrared spectra were recorded on a Shimadzu model IR-60 spectrometer. An ultrasonic bath was
used for the ultrasonic irradiation. The measurements were performed using PL- STA 1500
Thermal/Sciences in static air atmosphere. The samples were characterized with a field emission
scanning electron microscope (FESEM). X-ray powder diffraction (XRD) measurements were
performed using a Philips diffractometer of X'pert Company.
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Result and discussion
The thermal stability of complex nanoparticles was studied by thermal gravimetric (TG) and
differential thermal analyses (DTA). The XRD pattern matches the standard of hexagonal wurtzite
ZnO which are the same as the reported values (Zincite, JCPDS 36-1451). The Fourier transform
infrared (FT-IR) spectrum of calcinated sample has a strong band at 420 cm-1 attributed to Zn–O
stretch, in accord with previous reports. The average diameter of ZnO nanoparticles indicated in
the SEM image. Conclusion
ZnO nanostructure wasobtained by direct thermolyses of [Zn(DADMBTZ)(ac)2]n at 500°C under
air. The ZnO nanostructure was characterized by SEM, XRD and FT-IR spectroscopy. The
sonochemical method is rarely used for syntheses of new four coordinated complex. Synthesis of
ZnO nanstructured, making use of this method, is a novel approach in the literature.
References
[1] M. Salavati, F. Davar, A.Khansari, J. Alloys Compd 509, 61–65 (2011).
[2] P. X. Gao, Y. Ding, W. L. Wang, Nano Lett. 3, 1315 (2003).
[3]D. Xiang, Y. Zhu, Z. He, Z. Liu, Jin Luo, Mater.Res. Bull, 48 (2013) 188–193.
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Synthesis and photocatalytic activity of Bi 2 O 3 /Bi 2 O 4 /SnO 2
nanocomposite
Maryam Movahedi * 1 , Akram Hosseinian 2 , Azam Anaraki Firooz 3
1
2
3
Department of Chemistry, Payame Noor University, P.O. Box 19395-3697 Tehran, IRAN. Department of Engineering Science, University College of Engineering, University of Tehran, P.O. Box 11365-4563,
Tehran, Islamic Republic of Iran.
Dep. of chemistry, Faculty of science, Shahid Rajaee Teacher Training University, P.O. Box 167855-163 Tehran, Iran
Keywords. Photocatalyst, Nanocomposite, Bi2O3/Bi2O4/SnO2
Abstract.
In the present work, Bi2O3/Bi2O4/SnO2 composite has been successfully synthesized using the
precipitation method. The obtained sample was characterized by X-ray diffraction (XRD), Fourier
transform infrared spectroscopy (FT-IR) and emission scanning electron microscopy (FE-SEM).
The photocatalytic performance of Bi2O3/Bi2O4/SnO2 nano composite was evaluated by
decolorization of congo red solution under UV-vis irradiation. This work shows the possibility of
using of Bi2O3/Bi2O4/SnO2 nanocomposite as a photocatalyst for removal of anionic dye.
Experimental
1 Typical synthesis procedure for preparing SnO2:
The SnO2 was synthesized via solid state route using SnCl2.2H2O and NaOH. The product was
annealed at 500ºC for 1 h.
2 Typical synthesis procedure for preparing Bi2O3/Bi2O4/SnO2:
First, the prepared SnO2 was dispersing in 50 ml of (0.2 M) NaOH solution (Solution I). Second,
0.5 gr. Bi(NO3)3.5H2O was dissolved in (5 ml, 1 M) nitric acid solution (Solution II). Then, solution
(II) was slowly added drop wise into solution (I) under constant stirring. After stirring the mixture
for 30 min at 80º C the product was separated by decantation, washed with double distilled water
several times and dried at 60º C. Then, heat treatment of product was carried out at 600º C for 1 h.
3 Evaluation of photocatalytic activity
First, the dye solution of congo red (20 ppm) was prepared. A High presser lamp (400W Hg)
manufactured by Philips, Holland, was used as the light source. Air was blown into the reaction by
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an air pump to maintain the solution saturated with oxygen during the course of the reaction. During
the whole experiments, Photocatalyst amount was 0.5 g/l.
The structure of Bi2O3/Bi2O4/SnO2 nano composite was investigated by the XRD experiment. Fig
1(a) shows the XRD patterns of sample after calcinations at 600º C. As shown in XRD pattern
monoclinic (JCPDS No. 71-0465, JPDS No. 50-0864) and tetragonal phase (JCPDS No. 21- 1250)
were observed for Bi2O3, Bi2O4 and SnO2 respectively. The morphology of the Bi2O3/Bi2O4/SnO2
nano composite and SnO2 nano particle were studied by FE-SEM (Fig 1 b and c).FE-SEM image
indicated that the SnO2 sample was spherical in morphology with diameters of 78 nm.
Fig.1 (a) XRD pattern of the Bi2O3/Bi2O4/SnO2 (b) FE-SEM image of the Bi2O3/Bi2O4/SnO2 (c) FE-SEM image of the
SnO2
Photocatalytic activity of the prepared Bi2O3/Bi2O4/SnO2 was evaluated with congo red dye
solution as model contaminant under UV.vis irradiation. Decolorization of congo red solution (20
ppm) after 60 min UV.vis irradiation was 54%.
References
[1] L. Zhang, Y. Hashimoto, T. Taishi, I. Nakammura, Q.Q. Ni, Applied Surface Science 257
(2011)
[2] S. Lyyapushpam, S.T. Nishanthi, D.P. Padiyan, Material Letters 86 (2012) 25-27.
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Theoretical Study on the Host-Guest Interaction of Fullerene (C 60 ) with
Calix[5]arenes in the Gas Phase
Sadegh Salehzadeh * ,Yasin Gholieeand Mehdi Bayat
Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
Keywords:DFT Study, Fullerene, Host-Guest Chemistry, Calix[5]arenes
Introduction
C60 and its family represent an intriguing class of molecules due to their unique physical and
chemical properties. Their applications have been directed to many research areas such as
chemistry, material science, biology, etc. [1]. Supramolecular chemistry of fullerenes is one of
special interest due to the problem in purification of these molecules. Although a number of hosts
for fullerenes have been developed and the complexation both in solution and in the crystalline state
has been reported, thermodynamic study on this process in organic media is quite limited.
Pioneering works focused on its hydrophobic nature and spheroidal shape, and resulted in the
inclusion of C60 within water-soluble cyclodextrins and calixarenes, having the concave cavities
complementary to the exterior of C60 [2,3]. In this work we want to report a theoretical study on the
fullerene complexation with three calix[5]arenes (see Figure 1) in the gas phase.
1: X = Z = I, Y = CH3
2: X = Y = Z = CH3
3: X = Z = H, Y = CH3
Figure 1. Three calix[5]arenes studied here as host for fullerene.
To initiate the calculations for three host-guest complexes, the crystallographic structures of 1:C60,
2:C60 and 3:C60 were fully optimized without any symmetry constraints. The geometries of all
species in the gas-phase were fully optimized at B1B95 level of theory using the GAUSSIAN 03 set
of programs. The standard def2-SVP basis set was used in all calculations.
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The optimized structures of 1:C60, 2:C60 and 3:C60 in the gas phase are shown in Figure 2. the result
of calculations in the gas phase show the following trend for interaction energy (kcal/mol) between
the host and the guest molecules in these compounds:1:C60(7.9) >2:C60(7.7) >3:C60(7.6)
On the other hand, the experimental results suggest that the substitution of some of the methyl
groups of upper rim of the calix[5]arene by an atom with high polarizability slightly enhances the
association of fullerenes[3]: the host carrying two iodine groups on its upper rim provide the largest
binding constant, suggesting that dispersion force play an important role in the complex formation
between the host and the guest. Thus there is a good agreement between the experimental and
theoretical results.
1:C60
2:C60
3:C60
Figure 2. Optimized structures of the host-guest complexes studied here, at B1B95/def2-SVP level of theory.
Conclusions
The results, in agreement with experimental data, show that the substitution of some of the methyl
groups of upper rim of the calix[5]arene by an atom with high polarizability slightly enhances the
association of fullerenes.
References
[1] J. H. Schon, C. Kloc, B. Batlogg, Science 2001, 293, 2432.
[2] J. L. Atwood, G. A. Koutsantnis, C. L. Raston, Nature 1994, 368, 229.
[3] T. Haino, M. Yanase, G. Fukunaga, Y. Fukazawa, Tetrahedron 2006, 62, 2025.
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Nanocrystalline ZnS thin films preparation by solution growth
deposition (SGD) technique and study of nanocrystalls properties.
* ,1
1
Alireza Goudarzi, 2 Azimh Dorbygi Namghi
Polymer Engineering Department, Golestan University,P.O. Box 49188-88369, Gorgan, Iran
2
Chemistry Department, Payam Noor university of Sari,Sari, Iran.
*Email: [email protected]
Keywords: Thin films, Zinc sulfide, Nanocrystalls, Solution Growth Deposition.
Introduction
Zinc sulphide (ZnS) is an important II-VI semiconducting material with a wide direct band gap of
3.65 eV in the bulk. It has potential applications in optoelectronic devices such as blue light
emitting diodes; electroluminescent devices and photovoltaic cells [1].
In this research, the fabrication of nanocrystalline zinc sulfide thin films on glass substrates, and the
effects of different physical and chemical factors, such as: temperature, pH, concentration and
deposition time on properties of the obtained film by solution growth depositions (SGD) method
were investigated.
Materials
In this study, triethylamine, thioacetamide and zinc acetate were used as a complexing agent,
sulfide source and zinc source, respectively. The structural, morphological and optical properties of
the prepared ZnS films were determined by X-ray diffraction (XRD), field-emission scanning
electron
microscopy
(FE-SEM),
atomic
force
microscopy
(AFM)
and
Uv-visible
spectrophotometer, respectively.
The obtained FE-SEM image of the samples showed the dense grains (Fig. 1). FE-SEM images also
showed that the particles were well arranged and the average particle size increased with the
increase of deposition time (Fig.2). The obtained FE-SEM images of the ZnS thin films prepared at
different concentrations of Zn2+ ions showed that the ZnS films deposited at high molar
concentration have some big pinholes and cracks (Fig.3). The study of temperature effect on the
growth mechanism of ZnS thin films at various temperatures showed that when the deposition
temperature increases, the degree of crystallinity of the nanocrystallin ZnS thin film increases
which is due to the growth of the size of nanocrystallites. Surface morphology, roughness and
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thickness average of the prepared films were determined by AFM images (Fig. 4). The analysis of
XRD data revealed that the deposited films well-crystallized and have a cubic structure[2].
Fig. 1. FE-SEM image of the prepared
ZnS film (during 4h, and Zn Cons.
Fig. 2. FE-SEM image of the prepared
ZnS film (during 6h, and Zn Cons.
Fig. 3. FE-SEM image of the prepared ZnS
Fig. 4. AFMimage of the prepared ZnS
film (during 4h, and Zn Cons. =0.12M)
film(during 4h, and Zn Cons. =0.06M)
Conclusion
The results showed that the deposition time, temperature, concentrations of Zn2+ ions, and pH can
affect the composition, surface morphology, crystallinity, thickness, grain size and hence the
transmission spectra of the films. The composition of the films (measured by EDX) revealed the
presence of Zn and S without any impurities. The size of nanocrystals was estimated about 2 to
2.5nm.
References
[1] K.R. Murali, S. Vasantha, K. Rajamma, Materials letters 62 (2008) 1823-1826.
[2] Reza sahraei, Ghaffar Motedayen, Alireza Goudarzi. Journal of Alloys and Compounds 466
(2008) 488-492.
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Preparation and characterization of Ag-Cu bimetallic nanoparticles
with different morphologies using a wet-chemical method
P. Mashayekhi a* , M.Sadjadi a , A.banaei b
a
Department of chemistry, Science and Research branch, Islamic Azad university, Tehran, Iran.
b
Department of chemistry, Payame Noor university, Ardabil, Iran.
Key words: Wet-chemical, Silver-copper nanoparticles, Modifiers, Ascorbic acid.
Introduction
Bimetallic nanoparticles have excellent optical, electronic and catalytic properties different from
those of the component metals. Therefore much attention has been received for the development of
novel synthesis methods of bimetallic nanoparticles and their applications as catalysts, sensors and
substrates for surface enhanced Raman scattering [1]. Among many bimetallic nanoparticles, the
Ag-Cu bimetallic system has recently received strong attention due to their high electron
conductivity and application to lead free past [2]. More studied are required to develop simple
shape-controlled synthesis methods of Ag-Cu bimetallic particles.Our aim in this work
waspreparation of Ag-Cu nanoparticles with different morphologies at the presence different
modifiers by wet-chemical method. Silver nitrate and copper (II) sulfate was taken as metal
precursors, ascorbic acid at the presence of an appropriate amount of NaOH as reducing agent,
anhydride maleic and sulfuric acid as modifiers. The samples were characterized by scanning
electron microscopy (SEM) and X-ray diffraction (XRD).
In a typical process, silver nitrate (0.1M) and copper (II) sulfate (0.1M) were dissolved in de-ion
water, respectively. Moreover, different modifiers (Anhydride maleic 0.015M, Sulfuric acid
0.0015M) were added in the metal precursors solution. Then, the reductant (ascorbic acid 0.2M at
the presence of an appropriate amount of NaOH) solution was added in the silver nitrate and copper
(II) sulfate solution containing different modifiers with high-speed stirring and purging with N2 at
room temperature. The nanoparticles with different morphologies were prepared at the presence
different modifiers. After separation from the mixed solution, the precipitation was washed 3-4
times by de-ion water and then 2-3 times by ethanol.
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SEM and XRD patterns of silver-copper nanoparticles characterization:
When anhydride maleic was introduced as modifier, the particles shape spherical (Fig.1a).
Moreover, when sulfuric acid were introduced as modifier, mixture of spherical and hexagonal
particles were prepared (Fig.1b).
Fig.1a. show SEM image of the as-prepared of Ag-Cu nanoparticles with a anhydride maleic as modifier.
Fig.1b. show SEM image of the as-prepared of Ag-Cu nanoparticles with a sulfuric acid as modifier.
Fig.2a,b.represents powder XRD patterns of the samples prepared with two different morphologies.
Three peaks of Ag at 2θ= 38°, 44.4°, 64.5°, corresponding to the (111), (200), (220) lattice planes,
and two peaks of Cu at 2θ=43°, 50.5°, corresponding to the (111), (200) lattice planes, are observed.
All the diffraction peaks can be well indexed to face-centered cubic (Fcc) Ag ,Cu according to the
JCPDS cards (No.1-1167)and(No.4-836).
Fig.2a.XRD pattern of Ag-Cu nanoparticles shown in fig.1a.
Fig.2b.XRD pattern of Ag-Cu nanoparticles shown in fig.1b.
Conclusion
It implies that the modifiers play an important role in the controlled synthesizing of silver-copper
nanoparticles. In addition, if suitable modifiers are selected, it is possible to prepare silver-copper
nanoparticles with different shapes through the above processes.
Reference
[1] H. T. Zhang, J. Ding, G. M. Chow, M. Ran and J. B. Yi, Chem.Mater., 2009, 21, 5222.
[2] M. Tsuji, S. Hikino, R. Tanabe and D. Yamaguchi, Chem. Lett.,2010, 39, 334.
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Cure Kinetics and Degradation Studies of Epoxy Nanocomposite
Containing Polyaniline
M.Yaghoubi,A. Omrani * andA. A. Rostami
Faculty of Chemistry, University of Mazandaran, P. O. Box 453, Babolsar, Iran
([email protected])
Keywords: Polyaniline nanoparticles, Filler, Epoxy Resin, Cure Kinetics, Thermal analysis,
Ozawa Method.
Introduction
Preparation of PANI composites or blends is proposed as one of the most promising approaches to
produce novel conductive polymeric blends [1]. Recently, it has been demonstrated that blend based
on conductive PANI and epoxy resin could be produced as a conductive adhesive [2]. In this study,
polyaniline nanoparticles are prepared through micellar polymerization and its effect as nanofiller
on thermal properties of epoxy resin is investigated.
Experimental (or Computational) methods
Polyaniline nanoparticles synthesized via micellar polymerization technique using the method
described in the literature. The thermosetting matrix consisted of a bisphenol A epoxy resin as
matrix and 4,4'-oxydianiline as hardener were used. Blend compositions having 1, 3, 5, 10 wt.% of
PANI-DBSA were prepared and the thermal properties of the samples studied by DSC and TGA
techniques.The correlation between apparent activation energy, Ea, and the conversion, α, was
obtained by Ozawa method.
Data from DSC and TGA measurements were utilized to find a suitable model for describing the
kinetics of thermal degradation of the neat epoxy system and its nanocomposite.Results from TGA
measurements revealed that the thermal stability of the epoxy system improved by the addition
of polyaniline nanoparticles.The results also indicated that the degradation process obey a single
thermal process. The composition involving 5 wt% of the nanofiller has the highest amount of
glass transition temperature and enthalpy. The single process of degradation was statsfactorily
described by Coatse-Redfern kinetic algoritm.
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Ea
Ea
Ea
Ea
Ea
Harroitze-Metzger
Van-Croan
Coatse-Redfern
Flyn-Wall-Ozava
Kisinger
D1
D1
D1
----------
----------
225.14
208.4
197.76
185.94
165.86
Table 1. The activation energy of degradation calculated using various models
Conclusions
Addition of conductive polyaniline within epoxy matrix results in improved thermal stability and
conductivity. Aggregation of the nanofiller is being importance at high loading level of 10 Wt%. It
was recognized that the thermal degradation mechanism is controlled by a model that has been
known as one-dimensional diffusion (D1) model.
References
[1]. J. Anand, S. Palaniappan, and D. N. Sathyanarayana, Prog. Polym. Sci., 23, 993, 1998.
[2]. J.Peltola, Y.Cao, and P. Srnith, Adhes. Age, 38, 18, 1995.
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Study the Effects of Surface Area of Light and Heavy MgO on Carbon
Nanotubes Synthesized on MgO as Substrate Using CCVD Method
F. Tabatabaee ∗ ,A. A. Hosseini , M. Shadfar
Department of Physics, University of Mazandaran, Babulsar, Iran
[email protected]
Keywords: Carbon nanotubes, CCVD method, Surface area, Wet impregnation, Light MgO,
Heavy MgO
Introduction
Discovering of Carbon nanotubes (CNTs) by Sumio Iijima, was one of the most important scientific
events. The unique properties of CNTs (high Young modulus, extraordinary electrical and magnetic
properties and etc.) have made them useful and applicable in different fields like Nano electronics,
transportation, environment, pharmacy and etc.
As CNTs with different diameters have different characteristics, controlling this factor during the
synthesis process is of great importance. There are 3 main methods for synthesizing of CNTs:
Electric arc discharge, laser ablation and catalytic chemical vapor deposition (CCVD).
Among different methods of synthesizing of CNTs, CVD is of great importance because of its
simplicity and high product efficiency. In this method different porous materials can be used as
substrate like MgO. High surface area in porous substrate is an important factor in synthesizing
CNTs with high quality [1]. In this work light and heavy MgO have been used as substrates and
finally SEM images of the samples were used to compare the results.
Experimental
Catalyst nanoparticles have been produced using wet impregnation method. Iron and Cobalt salts
are the catalyst precursors and light and heavy MgO are two substrates. In order to form the metal
oxide nanoparticles on the external surface of the MgO, the nanoparticles were calcined at 650 .
Then the nanoparticles were put in a tubular furnace at 750
under a mixture flow of Acetylene
and Argon.
Results and discussions
SEM images of samples synthesized on heavy and light MgO are shown below. We can say that as
light MgO has a higher surface area than heavy MgO, more external surface is available for catalyst
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nanoparticles to be dispersed on. In this case, these nanoparticles are fixed on their primary place
and do not move with increasing temperature in calcination and synthesis processes [1].
Distribution of catalyst nanoparticles on a substrate with higher surface area increases the particles
access to hydrocarbon gas molecules and as a result decomposition rate of these molecules
increases [2]. So agglomeration decreases when light MgO is substrate, and consequently CNTs
with a lower average diameter are produced.
Fig.1. SEM image of CNTs synthesized on heavy MgOFig.2. SEM image of CNTs synthesized on light MgO
Conclusions
Using light MgO as substrate results in CNTs with a lower average diameter compared to using
heavy MgO.
References
[1]. Xu, Y.; Li, Zh.;Dervishi, E.;Saini, V.;Cui , J.;Biris, A. R.; Lupu, D
And Biris, A.S.J. Mat. Chem.2008, 18, 5738.
[2] .Dupuis, A.C. J.Mat. sci,2005, 50, 929
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Density functional theory study of carbon monoxide adsorption on the
outside of (4,0), (6,0), (8,0) zigzag and (4,4), (5,5) armchair singlewalled carbon nanotubes: A computational study
M. Madani * a ,A . A . salari a ,M. Noei b
a Department of Chemistry, Shahre Rey Branch, Islamic Azad University, Tehran, Iran
b Department of Chemistry, Mahshar Branch , Islamic Azad University ,Mahshahr, Iran
Keywords:Adsorption, Carbon monoxide, DFT, Nanotube
Introduction
Synthesis of carbon nanotubes (CNTs) by Ijima [1] caused a burst of activity by both physical and
chemical properties[1-3]. SWCNTs have a wide range of applications in nanoelectronics,
nanoscaling biotechnology, and biosensors[3, 4-7] .Because of their size, large surface area, and
hollow geometry, SWCNTs are being considered as prime materials for gas adsorption;biological,
chemical, and electromechanical sensors; and nanoelectronic devices.
In the first step, the structures were allowed to relax by all atomic geometrical optimization at the
DFT level of B3LYP exchange-functional and 6-31G**standard basisset. The binding energy of a
CO on the CNT wall was calculatedas follows:
Ead=ECNT-CO-(ECNT+ECO)+ᵟBSSE
where ECNT–OCN was obtained from the scan of the potential energy of the CNT molecular
carbon moxide, ECNT is the energy of the optimized CNT structure, and ECO is the energy of an
optimized CO, and ᵟBSSE is the BSSE correction.
A CO can approach the nanotube walls from outside (out), which is the most common case, and
from the inside (in). For the adsorption of the CO (O-down and C-down) on the CNTs, we
considered two sites (i.e., the C1, and C2 sites above the carbon atoms) as described in Fig.1. The
notation O-down and C-down denotes a CO perpendicular to the surface via O and C, respectively.
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Fig.1Adsorption modes of a CO on CNTs: C-down (a), and O-down (b)
We limited our analysis to the interaction of CO with the nanotubes’ outer walls. Considering each
site and configuration. For each of these cases we investigated the CNT–CO potential energy
surface (PES). In all pathways the potential is attractive, presenting a well of maximum ca. -130
kcal mol-1, which is characteristic of a chemisisorption process. The calculations showed that the
obtained adsorption energies depend on orientations and locations of CO, and the interaction
becomes rapidly repulsive as the molecule approaches the CNT wall.
Conclusions
On the basis of our calculations, it seems that pristine CNTs can be used as a CO storage medium as
long as CO is adsorbed on the exterior walls of the CNTs because of the high adsorption energy.
For the CNTs the calculated Ead for CO in O-down is more than that in C-down. We showed that
by increasing the nanotube diameter more efficient binding could not be achieved.
References
[1] Ijima S (1991) Nature 354:56
[2] Derycke V, Martel R, Appenzeller J, Avouris P (2002) Appl Phys Lett 80:2773
[3] Liu C, Fan YY, Liu M, Cong HT, Cheng HM, Dresselhaus MS (1999) Science 286:1127
[4] Zhou, O., Shimoda, H., Gao, B., Oh, S. J., Fleming, L., and Yue, G. (2002) Acc. Chem. Res., 35: 1045–1053.
[5] Zhen, Y., Postma, H. W. C., Balents, L., and Dekker, C. (1999) Nature, 402: 273.
[6] Baughman, R. H., Cui, C., Zakhidov, A. A., Iqbal, Z., Barisci, J. N., Spinks, G. M., Wallace, G. G., et al. (1999)
Science, 284: 1340–1344.
[7] Gao, H., Kong, Y., Cui, D., and Ozkan, C. S. (2003) Nano Lett., 3: 471–473.
1073
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Molecular Simulation Study of Noble Gas Adsorption onto Silicon
Nanotube
Z. Mahdavifar a , Z. Tabandeh * b
Computational Chemistry Group, Department of Chemistry, Faculty of Science, Shahid Chamran University, Ahvaz,
Iran
[email protected]
Keywords: Monte Carlo simulation, Silicon nanotube, Isosteric enthalpy, Separation factor.
Introduction
Due to the fundamental role of silicon in various chemical processes and microelectronics, this
material has been recognized as quite important in the previous century and continues to receive
considerable scientific and technological attention [1].According to this importance we studied the
gas adsorption behavior onto SiNT.
In this work, we investigate the adsorption of pure helium (He) and Argon (Ar) and their binary
mixture on single walled armchair type (6,6) SiNT by Monte Carlo simulation at 77 and 278 K. The
pressure range was varied from 1 to 30 MPa. In our simulation, the periodic boundary conditions
were imposed in all directions. A simulation box (50.0 Å * 50.0 Å *50.0 Å) contains one silicon
nanotube. There are several types of interaction such as gas– gas and gas–Si interactions are
considered. The total potential for the interaction between gas molecules and SiNT is calculated
using site-site interaction method :
Øfw = 4Ɛfw ∑
∑
where Nf is the total number of gas molecules. NSi is the total number of the silicon atoms at the
wall, and rij is the center-to center distance between a He and Ar with silicon atom from the SiNT.
In above equation, the subscript "fw" stands for interactions between a fluid molecule and the
silicon wall [2]. To obtain the adsorption isotherm Gravimetric storage capacity of gas (absolute
value adsorption per mass of adsorbent) was calculated from :
To compare adsorptive selectivity of He and Ar from He/Ar mixture, Separation factor, S, is
defined as:
/
/ He/
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where x and y are Mole fractions in the adsorbed and bulk phases, respectively. In addition, the
isosteric enthalpy of adsorption (Qst) is calculated using the following equation:
QST = - R∑
i
where N is the amount adsorbed, R is the gas constant, m determines the number of terms required
to adequately describe the isotherm.
All of the adsorption isotherms for pure and an equimolar mixture of Helium and Argon have a
Langmuir shape and no capillary condensation occurs. Results show that the amount adsorbed of
He and Ar increase with increasing gas pressure (Fig. 2). Also, with increasing temperature, the
amount of gas adsorbed is increased. As can be seen in Fig. 3, the isosteric enthalpies of adsorption
for He and Ar show gradual decreases in their values as a function of the amount of gas adsorbed.
Qst for Ar is larger than that for He under identical conditions and decreases with increasing
temperature.
Fig.2:Ar adsorption isotherms measured at 278 K
Fig.3: Isosteric enthalpy of Ar adsorption
on (6,6) SiNT at 77 and 278 K
Conclusions
In this research the separation of Helium and Argon is investigated using silicon nanotube. When
Sij > 1, component i is preferentially adsorbed; in contrast, if Sij < 1, component j is preferentially
adsorbed [3]. Results indicate that SiNT could be separated Ar easily from He gas which means that
the SiNT is suitable candidate for this purpose.
References
[1] Junga Ryou, Suklyun Hong,Solid State Communications, 148, 2008, 469–471
[2] J.Jiang ,Stanley I. Sandler, J. AM. CHEM. SOC, 2005, 127, 11989-11997
[3] Z. Bolboli Nojini, A.Rafati, M. Hashemianzadeh, S. Samiee, J Mol Model, 2011, 17,785–794
1075
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Conference
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Fabrication and Characterization of Polyethylene-Silver
Nanocomposites
M. Abareshi*, S.M. Shahroodi and V. Moeini
Dept. of Chemistry, Payame Noor University, 19395-3697 Tehran, I. R. of Iran
Keywords:Silver nanoparticle, Polyethylene, Nanocomposites, Mixer Mill.
Introduction
Metal-polymer nanocomposites have attracted considerable amount of interests in recent years. It is
generally known that mechanical milling is an excellent technique to produce a wide range of
materials with interesting properties [1]. It has many advantages such as low cost and high
efficiency [2]. Based on the literature survey, there is no any evidence of study concentrated on
polyethylene (PE)-silver nanocomposites. Thus, the main goal of this study is to fabricate PE-Ag
nanocomposites by mixer mill as a new method.
Methods &Characterization
Silver NPs were synthesized by reduction of silver nitrate in the presence of a reducing agent and
Polyvinylpyrrolidone as a stabilizer. Nanocomposites were prepared by mechanical milling of the
PE and Ag NPs in a mixer mill. PE and 5, 10, 20, and 30 wt% of Ag were mechanically mixed first
and then milled for 15 min. The microstructure of Ag and PE-Ag nanocomposites were
characterized by X ray powder diffraction (XRD), transmission electron microscopy (TEM), and
UV-Visible spectroscopy.
Fig. 1 shows the XRD pattern and TEM image of Ag NPs. Four diffraction peaks correspond to the
(111), (200), (220), and (311) planes of the face-centered cubic phase of silver crystal structure. The
mean particle size of Ag NPs according to the Debye–Scherrer equation is 25 nm, which is
confirmed with the TEM results. Fig. 2a shows the XRD patterns of pure PE with two crystalline
peaks at 2θ of 21.67o and 24.04o and one amorphous peak at 2θ of 19.81o. The presence of Ag and
PE peaks is observed from the XRD pattern of PE-Ag nanocomposite which is shown in Fig. 2b.
Fig. 3 shows the UV-Vis spectra of Ag Nps and PE-Ag nanocomposite. The extinction plasmon
band of Ag NPs at 403.5 nm (Fig. 3a) is indicative of monodisperse Ag NPs. Also, a UV-Vis
spectrum was ran for PE-Ag nanocomposite (Fig. 3b)) showing a band at 447.03 nm
which indicates the presence of Ag NPs in. The red shift of the absorption transition to higher
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wavelength when Ag NPs are dispersed in the PE matrix, may be due to the successful interaction
of Ag NPs with the PE chain. This result is similar to what Alam et al. proposed [3].
5000
(b)
Intensity (a.u)
Intensity (Counts)
(111)
4000
3000
2000
(200)
(220)
1000
(110)
(200)
(311)
(a)
0
20
30
40
50
60
70
2(Degree)
80
Fig. 1.The XRD pattern of Ag NPs, the inset is TEM
40
2(Degree)
60
80
Fig.2.The XRD patterns of pure PE(a) and PE-Ag10%
nanocomposite (b).
image of Ag NPs.
Control on the size, morphology and distribution of nanoparticles plays an important role in the
properties of nanocomposites. Thus to get a real idea what are happening inside the matrix system,
TEM was taken. The TEM image of the PE-Ag30% nanocomposite has been shown in Fig. 4. This
Absorbance (a.u)
figure indicates that the Ag NPs in general are well distributed in the PE matrix.
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
447.03 nm
(b)
403.5 nm
(a)
400
500
600
700
Wavelength (nm)
Fig. 3.The UV-Vis spectra of Ag NPs (a)and PE-Ag
Fig. 4.The TEM image of PE-Ag30% nanocomposite.
nanocomposite(b).
Conclusions
Silver NPs were synthesized and characterized using different methods. PE-Ag nanocomposites
were fabricated by mechanical milling as a new method. The resulting nanocomposites were
characterized by different techniques, such as XRD, TEM, and UV–Visible spectroscopy. The
results showed that the NPs were well dispersed throughout the PE matrix.
References:
[1] S. Doppiua, P. Solsonaa, et al. J. Alloys Compd. 404 (2005) 27.
[2] L.L. Wang and J.S. Jiang, Physica B. 390 (2007) 23.
[3] Alam et al. Arab. J. Chem. 6 (2013) 341.
1077
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Synthesize of Tin oxide nano-structures by CVD and investigationof
deposition period on gas sensing properties
R.S.HosseinianMobarake*, H.Haratizadeh, M.B.Rahmani
Department of Physics, University of Shahrood, Shahrood, Iran
([email protected])
Keywords:Chemical vapor deposition (CVD), Nano-structured sensor, Methane gas, Tin oxide
Introduction
Tin oxide (SnO2), a stable and large band gap (n-type) semiconductor, has been used widely in gas
sensors [1-2]. Mechanism of gas sensing for detection of a specified gas is variation of resistance in
presence of air and target gas in conductometric method. Nano-structured sensors have high
surface-to-volume ratiohence their response time to different species of gases is fast. Among them,
methane (CH4) is odorless and flammable gas that is dangerous. In this work nanostructures of tin
oxide were grown on alumina substrates using chemical vapor deposition (CVD)technique. In order
to investigation of deposition time on structural and sensing properties, three samples were prepared
in three periods of time (60, 90 and 120 mins). The structure of samples were studiedusing X-ray
diffraction (XRD) analysis (Advance Bruker D8). X-ray diffraction (XRD) analysis (Advance
Bruker D8) was used for studying structure and crystallite size of samples. Gas sensing properties
of samples were examined using a home-made gas sensing set-up by conductometric method.
Methods
For synthesize of SnO2 nanostructures, 0.5 gr of Tin powder, as precursor,was placed into an
alumina boat in electrical furnace and the source heated up to 1070 °C. A mixture of O2 and Ar
gases were used as carrier and reactant gases with flow of 100 and 300 sccm, respectively. Samples
were fabricated in three different time of deposition (60, 90 and 120 minutes for samples S1, S2 and
S3, respectively). In order to measure the gas response of the samples using conductometry method,
two Ag electrodes where deposited on two edges of the samples using silver paste.
Fig. 1 shows XRD analysis of samples which shows rutile structure for all samples. By increasing
the deposition time for samples up to 90 minutes (samlpe S2), crystal quality get better. Lattice
parametersfor S2 were calculated to be a=4.73 nm, c=3.18 nm. Crystallite size was estimated using
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Debye-Scherrer’s equation and obtained 12 nm. By increasing deposition time to 120 min (S3)
crystal quality get poorer.
In this work sensitivity of samples toward2000 ppm methane (CH4) in different temperatures(from
100-300 °C)was studied. CH4 is a reducing gas that exposing it to the surface reduce the resistance
of samples by realizing electrons via reacting pre-adsorbed oxygen species. Gas response of
samples toward CH4 were calculated from the relation ofSensitivity (%) =[(Rair-Rgas)/Rair]×100,
where Rair is the measured resistance of samples in air and Rgas is the resistance in the presence of
the target gas [2]. Results shows that with increasing temperature up to 250 ˚C, response of all
fabricated sensors increase. This is because of adsorption of increasing in contribution of oxygen
ions in reaction with gas.Above 250 ˚C decreasing in sensitivity was observed (Fig. 2).Sensitivity
of S2samples is better than others samples, which is because of better crystal quality and high
surface-to-volume ratio and better porosity so that exposed gas can more penetrate and hence
responseincrease.
Response (%)
Intensity (a.u.)
S3 (120 mins)
S1 (60 mins)
S2 (90 mins)
S1 (60 mins)
S3 (120 mins)
S2 (90 mins)
Operating Temperature (˚C)
2theta (deg.)
Fig. 1: XRD spectra of samples
Fig. 2: Sensitivity to 2000 ppm CH4
Conclusions
SnO2 nanostructures were successfully synthesized using CVD method. XRD Analysis of samples
confirms formation of rutile structure and phase. This work showed that deposition time is an
important parameter to grow nanostructures and improve sensing properties of SnO2. Samples
deposited in 90 minutes,because of better crystallinity, had higher sensitivity to 2000 ppm CH4 and
is suitable candidate for sensing.
References
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[1]. Lingmin, Y.; Xinhui, F.; Lijun, Q.; Lihe, M.; Wen, Y.; Applied Surface Science, 2010, 257,
3140.
[2]. Brown, J.R.; Haycock, P.W.; Smith, L.M.; Jones, A.C.; Williams, E.W.; Sensors and Actuators
B, 2000, 63, 109.
1080
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Conference
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Application of Fe 2 O 3 nano - structured sensor for detection of Liquefied
Petroleum Gas (LPG)
R.S. Hosseinian Mobarake *, H.Haratizadeh, M.B.Rahmani
Department of Physics, University of Shahrood, Shahrood, Iran
([email protected])
Keywords:iron oxide, LPG, nano-structured sensor, Physical vapor deposition (PVD)
Introduction
Liquefied Petroleum Gas (LPG) is a flammable gas and used as a fuel in heating appliances and
vehicles. For this reason, monitoring of this gas is necessary to provide safety in industry and life.
Gas sensors based on nano-structured metal oxide have good performance. Among them, iron oxide
(Fe2O3) is a suitable candidate for sensing ofthis gas. Fe2O3 is intrinsicallya p-type semiconductor
witha band gap of about 2.2eV [1,2]. Iron oxide nanostructures have been synthesized using various
techniques such as physical vapor deposition (PVD) (as in vacuum thermal deposition, sputtering
and etc.) and chemical methods (such as sol-gel, CVD and etc.). In this work we have utilized
vacuum thermal deposition for the deposition of Fe thin films on alumina substrates and then
thermal oxidation of this films to grow nano-structured Fe2O3 thin films. X-ray diffraction (XRD)
analysis (Advance Bruker D8) was used for studying structure and crystallite size of samples. Gas
sensing properties of samples were examined using a home-made gas sensing set-up by
conductometric method.
Experimental method
In the first step,for the synthesis of Fe2O3nano-structured samples, Fe powder was used as a source
material in boat for deposition of Fe films with thicknesses of about 50 and 100 nm (S1 and S2)
using vacuum thermal deposition. This films were deposited on alumina (Al2O3) pre-cleaned
substrates of dimension about 1×1 cm2. In the second step, Fe films were placedin quartz tube
furnace and then the tube was evacuated by a rotary pump to a rough pressure of 1×10-3torr. The
furnace, then was heated up to 800 °C under the flow of oxygen (flow rate of about 50 sccm) for 90
minutes. In order to measure the gas response of the samples using conductometry method, two Ag
electrodes where deposited on two edges of the samples using silver paste.
X-ray diffraction (XRD) method was used for studying structure and crystallite size of samples. The
results showed that S1 and S2 samples both have rhombohedral crystal structures (Fig. 1).
Crystallitesize and lattice constants were estimated from the highest intensity peak (Table1) that
indicates the nano-crystalline structure of the crystallites. Gas response of samples toward LPG
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were calculated from the relation ofSensitivity (%)=[(Rair-Rgas)/Rair]×100, where Rair is the
measured resistance of samples in air and Rgas is the resistance in the presence of the target gas [1].
For investigating the sensing properties of samples to LPG, a concentration of about 5000 ppm of
the gaswas used. Increment in resistance was observed by introducing the gas. Operating
temperature which is the temperature that sensor has the maximum of sensitivity, was 270 °C for
S1and 250 °Cfor S2which the latter was thicker. Response time of samples about, was 8 min for S1
and 5 min for S2 (Table1).
Fig.1: XRD pattern for the oxidized Fe films.
Table1: Crystal size, Constant lattice, Operating temperature, sensitivity for samples S1 and S2
Thickness
Crystal size
Constant lattice
Sensitivity (%)
Operating temperature
S1
50 nm
27.38 nm
0.2078 nm
21
270 °C
S2
100 nm
31.67 nm
0.2188 nm
25
250 °C
Conclusions
In this study nano-structured iron oxide synthesized for sensing LPG. XRD of samples showed that
both samples of different thicknesses have rhombohedral structure and that increasing thickness
shows enhancedcrystal size which causes increasing in the gas response. S2 with thickness of 100
nm was more sensitive to 5000ppm LPG.
References
[1].Balouria, V.; Kumar, A.; Samanta, S.; Singh, A.; Debnath, K.; Mahajan, A.; Bedi, R.K.;
Aswal, D.K.; Gupta, S.K.;Sensor and Actuator B , 2013, 181, 471.
[2]. Wei, Q.; Li, Z.; Zhang, Z.; Zhou, Q.; Materials Transactions, 2009, 50, 1351.
1082
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Conference
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Effect of substrate on the optical properties of MnFe 2 O 4 nanoparticles,
carbon nanotubes direct deposition method
N .Dehghan - niarostami * a , A.Moshrefzadeh a , F. Taleshi b , A.Pahlevan c
a
Department of Physics, Sience and Research Branch, Islamic Azad University, Sari, Iran
( [email protected])
b
Department of Applied Science, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
c
Department of Physics, Sari Branch, Islamic Azad University, Sari, Iran
Keywords:direct deposition MnFe2O4 nanoparticles, carbon nanotubes, Bandgap
Introduction:
In the last decade, magnetic nanostructures due to their chemical stability, non-toxicity,
biocompatibility and simple production process, many applications in different fields, especially in
biomedical engineering have been highly active and high level synthesis composites with different
characteristics have attracted the attention of many investigators. In this study, using iron nitrate (Fe
(No3) 2. 6H2O) and manganese chloride (MnCl2. 4H2O) in aqueous solution with ammonium
hydroxide using a reducing method to direct depositing nanoparticles and at MnFe2O4 calcined
were different. In these nanoparticles in aqueous solution containing different concentrations of
carbon nanotubes and the effect of substrate concentration and the effect of temperature on the
calcined ferrite nanoparticles was investigated. spectra of the samples using XRD and UV
performed. The results showed that the addition of carbon nanotubes and nanoparticles reduce
energy Bandgap also decreased with increasing size of nanoparticles calcined temperature increases
and increasedbandgap energy [1].
In this study we want to use carbon nanotubes as appropriate bed to control dimensions of optical
nanoparticles of MnFe2o4 and making nanocomposites powder. Testing process was done by using
direct precipitation method on nonmaterial synthesizing. First, without using nanotubes in a
chemical solution we optimize the ferrite nanoparticles experimental conditions. To preparing
samples we use iron nitrate salt (Fe (No3) 2. 6H2O) and magnesium chloride (MnCl2. 4H2O) in
aqueous solution with ammonium hydroxide to reduce duration of the synthesizing process. The
effects of parameters such as concentration and effect of calcification temperature with changing on
nanotubes concentration in solution was studied for MnFe2O4 nanoparticles synthesizing. Then
preparing nanoparticles in aqueous media containing carbon nanotubes with different
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concentrations and study its effect on nanoparticles synthesis. Characteristic features of samples
found by using XRD, and UV spectra.
Results and discussion:
Examples can be seen in the following figure, a, b, c, respectively, with an energy gap 4/32,
5/02and 5/08
is that it shows that the energy gap increases with the increase of calcined
temperature.
2 .0
0 .4
4
0 .3
M nFe2O 4
T=600
0
MnFe2O4
C
0
T=400 C
1 .5
3
0 .5

Abs(a.u)
0 .1
h

1 .0
h
Abs(a.u)
0 .2
2
1
0 .0
0 .0
-0 .1
400
600
 nm 
800
1000
1
2
3
4
5
6
200
300
400
h  ev 
500
600
700
800
900 1000
0
1
2
3
4
5
hev
nm
1.0
MnFe 2O 4
T=800
0
0.8
C
 h  

Abs(a.u)
0.6
0.4
0.2
0.0
300
400
500
600
700
800
900
1000
2
 nm 
3
4
5
h  ev 
Determination
The energy gap MnFe2O4 nanoparticles calcined at figure: a) 400° c b) 600 c) 800° c
Conclusions
nanoparticles MnFe2O4 calcined at 400, 600 and 800 ° C, particles with an energy gap 4/32, 5/02
and 5/08 have shown that increasing the particle size of the calcined temperature increases the
energy gap has also increased. The effect of carbon nanotubes on the substrate band gap manganese
ferrite nanoparticles in the present study using spectroscopy (UV-visible) was performed.
References
[1]. W. Q. Han, Zettl, Nano Letters 3(2003)681-683
1084
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Conference
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Effect of substrate on the morphology and magnetic properties of
MnFe 2 O 4 nanoparticles, carbon nanotubes direct deposition method
N .Dehghan - niarostami * a , F. Taleshi b , A.Pahlevan c
a
Department of Physics, Sience and Research Branch, Islamic Azad University, Sari, Iran
( [email protected])
b
Department of Applied Science, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
c
Department of Physics, Sari Branch, Islamic Azad University, Sari, Iran
Keywords:Magnetic nanoparticles MnFe2O4, morphology, carbon nanotubes
Introduction:
One of the most important magnetic materials, ferrite nanoparticles, has extensively been studied
because of their potential applications in magnetic storage media and magnetic resonance imaging
(MRI)[1]. The magnetic properties of these nanoparticles can significantly change depending on
their shape . These ferrites are attractive as well as from the theoretical point of view. In this
investigation the effect of carbon nanotubes as a support on the morphology, particle size and
magnetic properties of MnFe2O4
ferrite nanoparticles have been studied. Manganes ferrite
nanoparticles were prepared by a simple method based on direct deposition of carbon nanotubes in
aqueous solution. These samples were characterized by using the X-ray diffraction (XRD),
scanning electron microscopy (SEM), Fourier transform spectroscope (FT-IR) and vibrating sample
magnetometer (VSM). The results show that carbon nanotubes as a substrate had a significant
impact on the morphology and size of
MnFe2o4
nanoparticles decreases and it has been a
considerable increase in remnant magnetization.
In this study we want to use carbon nanotubes as appropriate bed to control dimensions of magnetic
nanoparticles of MnFe2o4 and making nanocomposites powder. Testing process was done by using
direct precipitation method on nonmaterial synthesizing. First, without using nanotubes in a
chemical solution we optimize the ferrite nanoparticles experimental conditions. To preparing
samples we use iron nitrate salt (Fe (No3) 2. 6H2O) and magnesium chloride (MnCl2. 4H2O) in
aqueous solution with ammonium hydroxide to reduce duration of the synthesizing process. The
effects of parameters such as concentration and effect of calcification temperature with changing on
nanotubes concentration in solution was studied for MnFe2O4 nanoparticles synthesizing. Then
preparing nanoparticles in aqueous media containing carbon nanotubes with different
concentrations and study its effect on nanoparticles synthesis. Characteristic features of samples
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found by using XRD, FT-IR and VSM spectra. For studying the morphology of the samples
scanning microscopic images (SEM) had been used. Explaining magnetic and morphologic
properties of these materials by SEM, VSM, and XRD graph comparing
In order to study the effect of magnetic nanoparticles on carbon substrate MnFe2O4, the ratio of 1 to
1 powder samples MnFe2O4/CNTs calcined at temperature( 600° C) spectra were obtainedVSM
range of nanocomposite powders MnFe2O4/CNTs can be seen above in the case of a ferromagnetic
material has been altered by the addition of carbon nanotubes and nanoparticles magnetic saturation
value of 0/2 g / emu to 46/53 g / emu increase has found ( Figure A) .VSM range of samples
MnFe2O4 calcined at temperatures (600° C) shows (Figure B). The resulting spectrum can be seen
that the material does not have any residual field and the coercivity, HC, is zero and the magnetic
saturation intensity 0/145 emu / g is measured.
0.15
0 .4
a
0.10
Magnetization(emu/g)
Magnetization(emu/g)
0 .3
0 .2
0 .1
0 .0
-0 .1
-0 .2
b
0.05
0.00
-0.05
-0.10
-0 .3
-0.15
-0 .4
-1 0 0 0 0
-8 0 0 0
-6 0 0 0
-4 0 0 0
-2 0 0 0
0
2000
4000
6000
8000
10000
-10000 -8000 -6000 -4000 -2000
0
2000
4000
6000
8000 10000
Applied Field(Oe)
A p p lied F ield (O e )
Figure a: VSM range of nanocomposite powder MnFe2O4/CNTs, figure b:VSM range of samples MnFe2O4 calcined at
temperatures (600° C)
Conclusions
The VSM images can be concluded that increasing the size of the nanoparticles calcined ̨ reduced
surface to volume ratio and reduced energy between the particles. Using carbon nanoparticles
MnFe2O4 as a growth substrate saturation magnetic nanoparticles has increased that represent
material change of position and change of Paramagnetism the ferromagnetic phase and the spin
arrangement [2].
References
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[1]. N. Rajkumar, D. Umamahaeswari, K. Ramachandran. (2010), photoacoustics and magnetic
studies of Fe3o4 nanoparticles. International Journal of Nanoscience Vol. 9, No3 243-250.
[2]. www.nanoclub.ir
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DFT study of effects of Ga-doped on (8, 0), (10, 0), (12, 0) zigzag model
of BPNTs
M. Rezaei - Sameti*, Sh. Rezaei , M. Farahani Farvazi, A. Khishvand
[email protected]
Abstract
After discovery of carbon nanotube (CNT) by Iijima [1], numerous researches have been focused to
investigate the properties and applications of new nanotubes that consist of groups III and V of
elements [2, 3]. Moreover, the new materials could be considered as promising candidates for future
electronics and optoelectronics applications because they are viewed as always wide gap
semiconductors [3]. To this time, the stable tubular structures of the counterparts of groups III and
V have been reported by either computations or experiments. In a recent work, we have studied the
structural and electrical properties of boron phosphide nanotube (BPNT), with different tubular
diameters and the effect of Ga-doped in spite of boron atoms on the structures’ parameters NMR,
HOMO, LUMO orbital properties [4-6]. For this aims we consider (8, 0), (10, 0) and (12, 0) zigzag
models of BPNTs by using DFT methods and B3LYP level of theory and 6- 31G (d) base set.
Computational method
The structural and electrical properties of (8, 0), (10, 0) and (12, 0) zigzag models of undoped and
Ga-doped of BPNTs (see Figs.1) are optimized. After optimizing all consider structures of
nanotubes, we calculate the chemical shielding (CS) tensors at the sites of 11B, 31P nuclei based on
the gauge included atomic orbital (GIAO) approach and same level of theory. The calculated CS
tensors in principal axes system (PAS) (  33   22   11 ) are converted to measurable NMR
parameters, chemical shielding isotropic (CSI) and chemical shielding anisotropic (CSA) by using
equations (1) and (2), respectively.
(1) CSI ( ppm)  1 ( 11   22   33 )
3
(2) CSA( ppm)   33  ( 22   33 ) / 2
Results discussions
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The optimized results revealed similar bond lengths for equivalent positions in the three forms of
BPNTs. By doping Ga the bond length of neighbor atoms is increased and for P doping is decreased
and the gap energy of (HOMO-LUMO),∆
, is significantly increased. The CSI
values for 9B sites neighbor with doping Ga atoms are slightly decreased, on the other hand for 31P
sites neighbor are significantly increased due to lone pair of electrons in valence shell of phosphor
and more electronegative of it. The result show the value of CSA of BPGaNTs model at the P82 site
is smallest.
Fig.1 3D structures of (8.0), (10,0), (12,0) zigzag models of BPNTs.
Key word: Boron phosphide nanotube, NMR, DFT, Ga-doped
References:
[1] S. Iijima, Nature 354 (1991) 56.
[2] J. Cheng , R. Ding ,Y. Liu, Z. Ding , L. Zhang, Comput. Mater. Sci. 40 (2007)341–344
[3] H. R. Liu, H. Xiang, X. G. Gong, J. Chem. Phys. 135 ( 2011) 214702
[4] M. Rezaei-Sameti, Physica E 44 (2012) 1770–1775
[5] M. Rezaei-Sameti Physica B 407 (2012) 3717–3721
[6] M. Rezaei-Sameti, Physica B 407 (2012) 22–26
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Comparison NQR and NMR parameters 3C-doped on BPNTs
M. Rezaei - Sameti, E.S. Dadfar, F - Saki
Department of Applied Chemistry, Faculty of Science, Malayer University, Malayer, 65174, Iran
[email protected]
Key word: Boron phosphide nanotube, NMR, NQR, , C-doped
Introduction
Since after the discovery of novel nano materials extensive investigation of adsorption on these
remarkable substrates have been done. Much of this effort has been directed toward potential
applications, such as gas storage, gas adsorption and gas separation, which exploit the fact that
every single-wall of nano tube can provide two surfaces, inside and outside of the tube, for potential
gas adsorption[1-5]. In this research the structural, quantum, NMR and NQR parameters of pristine
and C-doped on the (4, 4) armchair and (8, 0) zigzag models of boron phosphide nanotubes
(BPNTs) have been investigated by density functional theory (DFT).
For calculating the structural and electrical properties of (4, 4) armchair and (8, 0) zigzag singlewalled BPNTs (see Fig.1) we used density function theory at B3LYP level of theory using the
Gaussian 03 set of programs. The standard 6-31G* basis set was used for all models. All structural
of pristine and 3C-doped BPNTs are optimized and then, the chemical shielding (CS) tensors at the
sites of 11B, 31P nuclei are converted to measurable NMR parameters, chemical shielding isotropic
(CSI) and chemical shielding anisotropic (CSA) by using equations (1) and (2), respectively.
I
(1) CS ( ppm )  1 / 3( 11   22   33 )
A
(2) CS ( ppm)   33  ( 22   33 ) / 2
The NQR spectroscopy is used for nuclei that have I > 1/2 (I = nuclear spin angular momentum).
The calculated EFG tensor eigenvalues in the principal axis system (PAS) are converted into
measurable NQR parameters (nuclear quadrupole coupling constant (CQ), and asymmetry
parameter (ηQ)) using Eqs. (3) and (4). The standard Q values (Q (11B) = 40.59 mb) reported by
Pyykköare used Equations:
CQ (MHZ)  e2Qqzzh1
(3)
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Q  (qxx  qyy) / qzz 0  Q  1
(4)
Results discussions
We performed density functional theory (DFT) to calculate the CS parameters to investigate the
electronic structure and NMR properties of 3C-doped instead of boron atom in the armchair and
zigzag models of BPNTs. The results reveal that when 3C atoms are substituted in BPNTs, the bond
lengths, bond angles and gap of energy between HOMO and LUMO orbitals decreased. Due to the
donor electron effects of C doped instead of boron the CSI, CSA, CQ and ηQ values undergo
significant changes. The CSI values for B and P nuclei at neighbor of C-doped in two models are
increased and charge density electrons at these sites are bigger than other sites.
Figure 1 : 3D structure of (4, 4) armchair and (8,0) zigzag models of BPNTs
References
[1] W. Shi, J. K. Johnson, Phys. Rev. Lett., 91(2003) 015504 1-7.
[2] A. Kuznetsova, J. T. Yates, J. Liu, R. E. Smalley, J. Chern. Phys., 112 (2000) 9590-8.
[3] M. Rezaei-Sameti, Physica E. 44 (2012) 1770–1775
[4]
M. Rezaei-Sameti Physica B 407 (2012) 3717–3721
[5]
M. Rezaei-Sameti, Physica B 407 (2012) 22–26
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Utilizationof nanospinel NiMn 0.05 Fe 1.95 O 4 as the adsorbent in efficient
removal of azo dye reactive black 5 from aqueous solutions
Leila mohajeri haghi * , Iman Khosravi
Department of Chemistry, Islamic Azad University, saveh, Iran
([email protected]:Email)
Department of chemistry, Islamic Azad University, Qeshm, Iran
Keywords: Nanospinel; NiMn0.05Fe1.95O4; Adsorption; Azo-dye Removal; Reactive Black 5.
Introduction
Spinel compounds have a general formula AB2O4, in which the A-site(tetrahedral)are generally
occupied by divalent cations (Ni, and Zn)and the B-site(octahedral) are occupied by trivalent
cations(Cr, and Fe) .In this study, we investigatedutilization of nanospinel NiMn0.05Fe1.95O4as an
adsorbent for the removal of azo dye reactive black 5 (RB5) [1].
Experimental procedure
1. Preparation of nanospinel
NanospinelNiMn0.05Fe1.95O4were prepared by sol–gel method .The nanospinels were characterized
using X-ray powder diffraction(XRD)and transmission electron microscope(TEM).
.2. Dye removal experiments
The synthetic of dye solution was distributed into different flasks (1 L capacity) and pH was
adjusted with the help of the pH meter. The initial RB5 dye concentration in each sample was
50gL−1 after adding 0.01g of catalyst in 10 ml of the sample. All experiments have been performed
at room temperature.
1.1Effect of pH
Fig. 1 shows the percentage of removal rate of RB5 by NiMn0.05Fe1.95O4 nanoparticles depends
strongly on pH.
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Fig. 1. Effect of pH on RB5 removal by NiMn0.05Fe1.95O4. Experimental conditions: mass of adsorbent, 0.01 g; initial
dye concentration, 50 mgL−1; volume of dye solution, 10 ml; temperature, 25 ◦C; time, 10 min.
1.2The effect of contact time
Increasing contact time from 1 to 15 min eventuate to increase in the percentage of removal rate
from 70.6 to 86.4, respectively.
1.3The effect of adsorbent concentration
The results showed that increasing the number of binding sites, as the adsorbent dose increases,
the percentage removal of dye also goes up[2].
2.Chemical kinetic removal models
Adsorption kinetics showed that the reaction conform to the second-order rate equation.
3.Adsorption isotherms
The isotherm evaluations revealed that the Freundlich model provides better fit to the experimental
data than that of the Langmuir model[3].
4.Photocatalytic activity measurement
The photocatalytic degradation of RB5 at pH 1 under UV irradiation was examined. The results
showed that the degradation of RB5 dye follows merely an adsorption process[4].
Conclusions
The adsorption studies have been carried out for contact time, different pH values and adsorbent
doses separately. NiMn0.05Fe1.95O4 nanoparticles have been also proven to removal azo-dye RB5 at
pH= 1 effectively. The results show the NiMn0.05Fe1.95O4 nanoparticles can effectively remove high
concentrations of RB5 dye molecules. The second-order kinetic model is more successful in
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representing the experimental data for the removal of RB5 on NiMn0.05Fe1.95O4nanoparticles. The
isotherm modeling reveals that Freundlich equation describes the adsorption of RB5 dye onto the
NiMn0.05Fe1.95O4 better than the Langmuir model. Experimental results of the photocatalytic
decolorization of the azo-dye RB5 using NiMn0.05Fe1.95O4 reveal that the decolorization can be
achieved by an adsorption process.
References
[1] P. Parhi, V. Manivannan, J. Eur. Ceram. Soc. 28 (2008) 1665–1670.
[2] G. Moussavi, M. Mahmoudi, J. Hazard. Mater. 168 (2009) 806–812.
[3] H. M. F. Freundlich, J. Phys. Chem. 57 (1906) 385–471.
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Removal of azo dye reactive black 5 from aqueous solution Using
ZnCo 2 O 4 nanospinel
Leila mohajeri haghi * , Iman Khosravi
Department of Chemistry, Islamic Azad University, saveh, Iran
([email protected]:Email)
Department of chemistry, Islamic Azad University, Qeshm, Iran
Keywords: Nanospinel; ZnCo2O4; Adsorption; Reactive Black 5; Second-order kinetic.
Introduction
Azo dye in various industries due to aromatic rings and N=N bond provides problems for the
aquatic and mammals such as carcinogen, toxicity and mutagenicity [1]. The removal of dyes from
aqueous solution with regard to this issue seems necessary.This study has investigated the
efficiency of nanospinels, ZnCo2O4, as an adsorbent for removal of azo dye, reactive black 5 (RB5),
from an aqueous solution[2].
Experimental procedure
1. Preparation of nanospinel
Nanospinel ZnCo2O4 were prepared by sol–gel method .The nanospinels were characterized
using X-ray powder diffraction (XRD) and transmission electron microscope (TEM).
2. Dye removal experiments
The synthetic of dye solution was distributed into different flasks (1 L capacity) and pH was
adjusted with the help of the pH meter (HOBIRA D14E). The initial RB5 dye concentration in each
sample was 50 mgL−1 after adding 0.01g of catalyst in 10 ml of the sample. All experiments were
conducted at 25ºC and the pH values 1, 7 and 11.
1.Dye removal by ZnCo2O4 nanoparticles
The adsorption studies have been carried out for different pH values, contact time, different
temperatures and adsorbent doses.
1.1Effect of pH
Solution pH is an important parameter that affects adsorption of dye molecules.The removal of
RB5 dye above 94.6 % was achieved at pH = 1.This pH has been selected for investigating for the
further experiments.
1.2The effect of temperature
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Increasing temperatures from 15 °C to 45 °C eventuate to increase in the percentage of removal
rate from 87.8 to 96 %, respectively. Accordingly, the adsorption of RB5 using nanoparticles is a
kinetically controlled process.
1.3The effect of contact time
The removal efficiency of RB 5 increased from 93.2% in the first minute of contact to 94.6% as
the stirring was increased to 15 min, when the equilibrium condition was attained[3].
1.4The effect of adsorbent concentration
The results showed that as the adsorbent dose increases, the percentage removal of RB5 dye also
increases.
2.Chemical kinetic removal models
To find the suitable chemical removal model for describing the experimental kinetic data, the
obtained data were fitted with the first and second-order models. The results of experimental for the
two models show that the removal of RB5 dye is done in second-order kinetic with rate constant of
0.005 M-1min-1[4].
3.Adsorption isotherms
The isotherm evaluations revealed that the Langmuir model attained better fits to the experimental
equilibrium data than the Freundlich model.
Conclusions
In this study, we investigated utilization of ZnCo2O4 nanospinels as an adsorbent for the removal of
azo dye reactive black 5 (RB5). The results indicated that the prepared nanoparticles can effectively
remove high concentrations of RB5 dye molecules from aqueous solutions. Isotherm modeling
reveals that Langmuir equation could better describe the adsorption of RB5 dye onto the
ZnCo2O4nanospinels as compared to the Freundlich model. Adsorption kinetics was found to
conform to the second-order rate equation.
References
[1] K. Vijayaraghavan, Y. S. Yun, Biotechnol. Adv. 26 (2008) 266–291.
[2] X. Lou, X. Jia, J. Xu, S. Liu, Q. Gao, Mater. Sci. Eng. A 432 (2006) 221–22
[3] A. Olgun, N. Atar, J. Hazard. Mater. 161 (2009) 148–156.
[4] Y. S. Ho, G. McKay, Process Biochem. 34 (1999) 451–465.
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The effect of phenyl groups on the electronic properties and stability
of tetracene molecule
S.Alizadeh* 1 ,2 , N. Shahtahmassebi 1 ,2 , R. Pilevarshahri 3
1
2
3
Nanoresearch Centre of Ferdowsi University of Mashhad,Iran
Physics Dep., Faculty of Sciences, Ferdowsi University of Mashhad, Iran
Physics Dep., Faculty of Sciences, Payamenoor University of Neyshaboor, Iran
Keywords: Phenyl , Tetracene , Ruberene , DFT
Introduction
Molecules of the n-Acens family, C4n+2H2n+4,form an important class of organic compounds with
very intriguing properties. In recent years, however, there has been a growing interest in the in their
electronic properties and a large number of papers have been reported[1]. Because of their high
charge carrier mobility ,they are commonly used in organic field effect transistors (OFET)[2],
organic light emitting diodes (OLED)[3] and organic photovoltaic cells[4]. But unfortunately they
have a little structural stability. To improve their stability and some of their other
important
properties, significant effort are being made to synthesize functionalized acens in which different
chemical groups are replaced by hydrogens. In this study, we present a theoretical investigation of
the structural and electronic properties of of tetracene molecule (n=4) by adding different number
of phenyl groups at various positions in the molecule.
The electronic structure and total energy of the system at each configuration is calculated by using
density functional theory (DFT) and GGA exchange-correlation functional using SIESTA code.
First, we calculate the electronic structure of tetracene molecule(fig1-a) ,tetracene with two phenyl
groups(fig1-b) and tetracene with four phenyl groups(fig1-c).The density of states of these
molecules are shown in fig2 and the calculated HOMO-LUMO gap and total energy are given in
table1. We find that the addition of different number of phenyl groups to the tetracene molecule
reduces the size of the HOMO-LUMO gap(fig2,table1) which make rubrene more appropriate for
the use in electronic devices, it also increase the stability of the molecule significantly as compared
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to tetracene (table1).Then, we examine the effect of different positions of four phenyl groups on the
electronic structure and stability of tetracene(see table2).
a)
b)
c)
Figure2: Density of states (DOS) of tetracene,
Figure1:
5,11-diphenyl tracene, (Rubrene)
tetracenec)
HOMO-LUMO
Total Energy
gap(ev)
(ev)
1.72044
-2972.479323
Tetracene
1.68213
-4954.081937
5,11-diphenyl tetracene
1.61861
-6935.211441
Rubrene
HOMO-LUMO
Total Energy
gap(ev)
(ev)
1.61861
-6935.211441
Rubrene
1.65723
-6935.502133
2,5,6,9-tetra phenyl tetracene
1.69901
-6935.688092
2,3,8,9- tetra phenyl tetracene
a)
Tetracene,
5,6,11,12-tetra
b)
phenyl
Table1:Comparison
HOMO-LUMO
5,11-diphenyl
gap
tetracene
of
and
total energy of tetracene
with different number of
Table2: The comparisonof
HOMO-LUMO
gap
and
total energy of tetracene
with four phenyl groups in
When we move phenyl groups away from the center of the tetracene , the HOMO-LUMO gap
increase while the stability does not change significantly. Consequently these results show that
rubrene is more favorable compound than other phenyl substituent tetracene derivatives to use in
electronic devices.
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Conclusions
In this study we investigate the effect of phenyl groups on the electronic structure and stability of
tetracene using density functional theory.We examine different number of phenyl groups on various
positions to find the most stable functionalized tetracene with the smallest size of HOMO-LUMO
gap. We find that rubrene is a good candidate for this perpose.These results can be used in organic
electronic devices.
References
[1]: D. Chun, Y. Cheng and F. Wudl,Angew . Chem.120, 8508 (2008)
[2]: J. E. Anthony , Angew. Chem., Int. Ed. 47, 452 (2008)
[3]: M.A.Wolak, B.B.Jang, L.C.Palilis , Z.H.Kafafi , J. Phys.Chem. B,108,5492 (2004)
[4]: B.P. Rand, J. Genoe, P. Heremans and J. Poortmans , Prog. Photovoltaics 15, 659 (2007)
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Synthesize and Characterization of Multifunctional Silica Coated
Magnetic Nanoparticles using Polyvinylpyrrolidone (PVP) as a
mediator
M.S. Sadjadi* 1 ,a , F. Fathi 1 ,b , N. Farhadyar 2, c , K.Zare 3 , d
1Department
of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran
2Department
of Chemistry, Varamin -Pishva Branch, Islamic Azad University, Tehran, Iran
3Department
of Chemistry, Shahid Beheshti University,Tehran, Iran
[email protected]
Keywords: Magnetic Iron oxide, Surface modification, polyvinylpyrrolidone.
Abstract. Magnetic iron oxide nanoparticles with proper surface coatings are increasingly being
evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance
imaging, transfection and cell/protein separations. In this work, silica coated iron oxide magnetic
nanoparticles, which are very useful for delivering chemotherapeutic drugs, has been prepared by
precipitation in an aqueous solution of iron (II) and iron (III) chlorides under basic condition. In this
process, polyvinylpyrrolidone (PVP) has been used as a stablizer. Surface modifications of the asprepared Fe3O4 Nps have been carried out by using tetraethoxysilane (TEOS). Silica coated
nanoparticles have been characterized by Fourier transform infrared (FTIR) spectroscopy, Powder
X- ray diffraction (XRD), Transmission electron microscopy (TEM) and Infrared (IR) spectroscopy
Introduction
The coprecipitation method, as an economic, biocompatible, and environmentally friend method,
has been used for synthesizing Fe3O4 nanoparticles, but ultra-small Fe3O4 nanoparticles have not
been successfully synthesized by this method yet. In this paper, we report the synthesis of ultrasmall Fe3O4 nanoparticles at 75°C by the coprecipitation method using polyvinylpyrrolidone (PVP)
as a stabilizer. PVP molecules providing pyrrolidone functional groups can easily arrest crystalline
growth of Fe3O4 nanoparticles and can help formation of ultra-small magnetic particles by stopping
the nanoparticles aggregation. In order to improve the performance of the PVP coated Fe3O4 NPs,
we carried out its surface modification using TEOS. Successful synthesis of the ultra-small silica
coated Fe3O4 nanoparticles by this way has been confirmed by means of X-ray diffraction (XRD),
transmission electron microscopy (TEM) and infra spectrum (IR).
Experimental
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Required amounts of FeCl2 .4 H2O and FeCl3.6H2O in molar ratio of 1:2 were dissolved in 200 ml
of deaerated distilled water in a round bottom flask and kept at a desired temperature. After 30
minutes purging of the stirred reaction mixture with nitrogen, stoichiometric amount of NaOH was
added drop wise into the solution. During the experiment, nitrogen gas was kept passing through
the solution to prevent oxidation of Fe2+ in the system and addition of NaOH, was noticed the
solution changed color from the original brown to dark brown and then to black. This physical
change property is very sensitive to the solution pH and is helpful in separation of the particles from
the liquid reaction solution.PVP coated iron oxide nanoparticles were
prepared by adding the above prepared black precipitate to a solution of PVP (10% w/w) previously
purged with nitrogen gas. The resulting product was centrifuged and washed 3 times by deionized
water and acetone and dried in an oven at 35°C for 24 hours.
For preparation of silica-coated magnetic nanoparticles, sol–gel process has been adopted for its
advantages compared with the other methods, i.e. relatively mild reaction condition, low cost and
surfactant free. Hydrolysis and condensation of TEOS of a suspension of magnetic nanoparticles in
TEOS leads to the formation of a layer of silica around the magnetic nanoparticles.
Results and Discussions
Figure 1(a,b,c) represents FTIR spectra of neat PVP, PVP coated magnetite nanoparticles and silica
mdified magnetite Fe3O4 nanoparticles. The shift of the carbonyl vibrational band from 1659 cm-1
to 1634 cm-1 in the nanocrystal samples, suggests that PVP is coordinated on the surface of the
Fe3O4 nanocrystals via interaction through its carbonyl group. But no change has been observed for
the peak of N-OH (at 1291 cm-1) which was weakened greatly. These changes of intensity can be
attributed to the coordination between N-OH and iron oxide nanoparticles [19]. The broad intense
absorption peak at around 564 cm-1 can be attributed to lattice absorption of the Fe3O4 particles.
Infrared analysis of the PVP coated Fe3O4/ SiO2 samples (Fig. 1c) confirms the presence of the
finger print bands below 1100 cm-1 which are characteristic of asymmetric (1097 cm-1) and
symmetric (810 cm-1) stretching vibrations of framework Si-O-Si. The original assignments of the
main IR bands are as follows: internal tetrahedra 1250 - 920 cm-1, asymmetrical stretch (νasym);
720 - 650 cm-1, symmetrical stretch (νsym); 500 - 420 cm-1, T-O bend; external linkages: 650 500 cm-1.The peaks observed in XRD patterns were consistent with those
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of standard XRD pattern of Fe3O4 and confirm crystallinity of Fe3O4 nanoparticles and reveal that
successive addition of TEOS with a basic catalyst has generated silica coating on nanocrystals. The
crystalline size of Fe3O4 at the characteristic peak was calculated by Scherrer formula as follows:
D = Kλ/β 1/2 cosθ
While the absence of (210) and (300) peaks in this recorded XRD pattern show that separate
maghemite (γ-Fe2O3) is not present in the samples.TEM image of PVP coated Fe3O4 indicating
the size and morphology of nanoparticles. This figure clearly shows that the ultra small size of iron
oxide nanoparticles were coated with PVP and the size of PVP coated spherical nanoparticles was
about 10 nm. This value is in good accordance with the particle size calculated using Sherrer
formula for Fe3O4 core.
References
[1] ZD. Zhang Nanocapsules. In: Nalwa HS, editor. Encyclopedia of nanoscience and
nanotechnology, vol. 6. Stevenson Ranch, CA: American Scientific Publishers; (2004), 77–160.
[2] HW. Gu, KM. Xu, CJ. Xu, B. Xu, Biofunctional magnetic nano-particles for protein separation
and pathogen detection, Chem. Commun. (2006) 941–9.
[3] BM. Osca, PM. Maria, T. Pedro, RC. Jesus, B. Pierre, S. Martin, et al. Fe-based nanoparticles
metallic alloys as contrast agents for 395 magnetic resonance imaging, Biomaterials 26 (2005)
5695–703.
[4] HY. Xie, C. Zuo, Y. Li, ZL. Zhang, DW. Pang, XL. Li, et al. Cell-targeting multifunctional
nanospheres with both fluorescence and magnetism, Small 1 (2005) 506–9.
[5] Tanaka H, Sugita T, Yasunaga YJ, Shimose SJ, Deie M, Kubo T, et al. Efficiency of magnetic
liposomal transforming growth factor-β 1 in the repair of articular cartilage defects in a rabbit
model, J. Biomed. Mater. Res. 73A (2005) 255–63.
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Synthesis and characterization of PVP coated ultra-small Fe 3 O 4
nanowires
Sadjadi M. S. 1 *, Fathi F. 1 , Farhadyar N. 2 and Zare K.
3
1. Department of chemisty, Science and Research Branch, Islamic Azad University, Tehran, IRAN 2. Department of
Chemistry, Faculty of Basic Sciences,Varamin –pishva Branch , Islamic Azad University, IRAN 3. Department of
chemistry, University of Shahid Beheshti, Eveen, Tehran, IRAN
[email protected]
Abstract
In this work, coated iron oxid magnetic nanoparticles, called carriers, which are very useful for
delivering chemotherapeutic drugs has been prepared by precipitation in an aqueous solution of iron
(II) and iron (III) chlorides under basic condition. Surface modifications were carried out by using
polyvinylpyrrolidone (PVP). The results obtained from FTIR spectroscopy and XRD and TEM
revealed that the PVP molecules in the coated magnetite particles were bounded.
Keywords: Polyvinylpyrrolidone; Supermagnetic iron oxides; nanowires, Magnetic resonance
imaging
Introduction
Magnetic nanoparticles (especially, iron-oxide nanoparticles) have attracted intensive attention in
biomedical applications, such as separation of biomacromolecules, magnetic resonance imaging
(MRI), biological labels and targeted drug deliverythe synthesis of ultra-small Fe3O4 nanoparticles
with size less than 10 nm is highly desired for biomedical applications. coprecipitation method has
been used for synthesizing Fe3O4 nanoparticles. In this paper, we used polyvinylpyrrolidone (PVP)
as a stabilizer to synthesize ultra-small Fe3O4 nanoparticles at 75°C by the coprecipitation method.
The successful formation of the ultra-small Fe3O4 nanoparticles was confirmed by means of X-ray
diffraction (XRD), transmission electron microscopy (TEM), infra spectrum (FTIR), and X-ray
photoelectron spectroscopy (XPS).
Experimental
Required amounts of FeCl2 .4 H2O and FeCl3.6H2O in a molar ratio of 1:2 were dissolved in 200 ml
of deaerated distilled water in a round bottom flask and kept at desired temperature. After 30
minutes purging of the stirred reaction mixturewith nitrogen, stoichiometric amount of NaOH was
added drop wise into the solution. During the experiment, nitrogen gaz was kept passing through
the solution to prevent oxidation of Fe2+ in the system and addition of the NaOH, was noticed the
solution changed color from the original brown to dark brown and then to
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black. The black iron oxide product responded to a magnetic field as expected. This physical
property is very sensitive to the solution pH and is helpful in separation of the particles from the
liquid reaction solution.The polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles were
prepared by adding the above prepared black precipitate to a previously purged solution of PVP
(10% w/w) with nitrogen gas to remove oxygen. Resulting product was centrifuged and washed 3
times by deionized water and acetone and dried in an oven at 35°C for 24 hours.
FTIR spectra of neat PVP and PVP modified magnetite nanoparticles are shown in Fig. 1. The shift
of the vibrational band of the carbonyl group from 1659 cm-1 to 1634 cm-1 in the nanocrystal
samples, suggests that PVP is modified on the surface of the Fe3O4 nanocrystals via change has
been observed for the peak of N-OH (at 1291 cm-1) which was weakened greatly. These changes of
intensity can be attributed to the coordination between NOH and iron oxide nanoparticles. The
broad intense absorption peak at around 564 cm-1 can be attributed to lattice absorption of the
Fe3O4 particles. The XRD patterns of PVP modified magnetite nanoparticles, Fe3O4 compared to
neat Fe3O4 molecules are shown in Fig. 2. The peaks observed in this pattern were consistent with
those of standard XRD pattern of Fe3O4 and confirm crystallinity of Fe3O4 nanoparticles. The
crystalline size of Fe3O4 at the characteristic peak was calculated by Scherrer formula as follows: D
=Kλ/β 1/2 cosθ
The TEM image of PVP coated Fe3O4 indicating the size and morphology of nanoparticles This
figure clearly shows that the size of PVP coated spherical nanoparticles is about 10 nm. This value
is in accordance with the particles size calculated hsing Sherrer formula for Fe3O4 core.
References
1. Babes L., Denizot B., Tanguy G., Le Jeune J.J. and Jallet P.,Synthesis of iron oxide nanoparticles used as
MRI contrast agents: A parametric study, Journal of Colloid and Interface Science, 212(2), 474‐482 (1999)
2. Gu F.X., Karnik R., Wang A.Z., Alexis F., Levy‐Nissenbaum E., Hong S., Langer R.S. and Farokhzad
O.C., Targeted nanoparticles for cancer therapy, Nano Today, 2(3),14‐21 (2007)
3. Moghimi S.M., Hunter A.C.H. and Murray J.C., Longcirculating and target-specific anoparticles: theory
to practice, Pharm Rev, 53, 283–318 (2001)
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I-V Characterization of GaN nanoribbons using non-equilibrium Green
function method
M.saeedi; (2)
M.Bezi Javan*(1)
(1) Physics department, sari branch, Islamic azad University , sari, Iran ([email protected])
(2) Physics department, Golestan university , Gorgan, Iran ([email protected])
Keywords: tight-binding, non-equilibrium Green's function, conductance, I-V characteristic,
GaN nanoribbons.
Using tight binding approach we have investigated I-V characterization of a numbers of GaN
nanoribbons with different topological symmetry i.e. zigzag and armchair States, with combination
of non-equilibrium Green function method (NEGF). We have found that the transmission and
electrode-molecule coupling factor are strongly dependent to the topologic states of 2D GaN
nanoribbons. We Also found that the I-V curve depend on the number of Ga-N rings of the ribbons.
We also firstly present the DOS and conductance of the famous GaN semiconductor 2D ribbons.
References
s.Datta,"Quantum Transport:Atom to Transistor",(Cambridge University Prees,Cambridge,UK,2005)]1[
[2]M.L.Cohen and J.R.Chelikowsky, "Electronic Structure and Optical Properties of Semiconductors", 2nd Ed. (Springer
–Verlag, Berlin, 1989)
A.Yoshihiro,F.Hidetoshi,Phys.Rev.B72(2005) 085431]3[
[4]M.Ashhadi, S.A.Ketabi, N.Shahtahmassbi, D.Vahedi Fakhrabad,M.Askari," The role of impurities on the properties
of electron transport through the metal/trans- PA/metal System: Green's Function approach", physica E 43 (2011) 924928.
[5]Prashant Damle,Avik W.Ghosh,s. Datta," First-Principles analysis of molecular Conduction Using quantum
chemistry software", Chemical Physics 281 (2002) 171-187.
30
20
N
Ga
Ga
2ring
10ring
3ring zigzag
10ring zigzag
N
N
N
Ga
10
N
N
Ga
5
current(I)
current(I)
10
0
-10
-20
Ga
15
Ga
Ga
N
Ga
N
Ga
N
Ga
N
Ga
N
0
-5
-10
-30
-15
-10
-5
0
5
10
voltage(V)
-10
-5
0
voltage(v)
0.09
Total conductance versus coupling
160
0.08
0.07
140
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120
100
0.05
0.04
current
l0g(g/g0)
0.06
80
Total current versus coupling
5
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2 ring armicher
2 ring armicher
log(g/go)
1
Total current versus voltage
180
3 ring
0.9
3 ring zigzag
160
0.8
140
120
0.6
100
current
log(g/g0)
0.7
0.5
0.4
80
0.3
60
0.2
40
0.1
0
0
20
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
0
tc
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
coupling electrode and molecule
1
10
2
10
log(Density Of States)
0.1
0
10
-1
10
-4
-3
-2
-1
0
0
10
-1
10
-2
2 ring armicher
-2
10
1
10
10
1
2
3
10 ring armicher
-5
Energy(ev)
-4
-3
-2
-1
0
1
2
3
2
3
4
Energy(ev)
2
10
3
10
2
10
1
10
0
10
-1
10
-5
-4
-3
-2
0
10
-1
10
-2
10
3 ring
-2
10
1
10
-1
0
1
2
3
4
10 ring zigzag
-5
Energy(ev)
-4
-3
-2
-1
0
Energy(ev)
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Molecular dynamics simulation of structural properties of
a polymer nanocomposite
Hossein Eslami, Marzieh Behrouz
Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
Keywords: Simulation, Structure, Nanocomposites, Polyamide-6,6.
Introduction
Polymer nanocomposites are a new class of composite materials, receiving a significant attention
both in academia and industry. Compared to different nanofillers, carbon nanotubes have emerged
as the most promising nanofiller for polymer composites due to their remarkable mechanical,
electrical and thermal properties [1]. The purpose of this study is to simulate a polymer/nanotube
nanocomposite in order to shed light on its structural properties from a fundamental point of view.
Method
In this work, molecular dynamics (MD) simulations have been performed for 80 chains of
polyamide-6,6 (PA-6,6) decamers in contact with carbon nanotubes of different diameters. The
simulations were performed in the canonical ensemble at 500 K using YASP simulation package
[2]. The single walled carbon nanotubes were (6,0), (10,0) and (17,0) nanotubes. The force-field
parameters for both carbon nanotube and PA-6,6 are taken from the literature [3]. The cutoff
distance of the Lennard-Jouns potential was chosen to be 0.9 nm. Newton’s equations of motion
were integrated by using the Leap-frog algorithm with a time step of 2 fs. The results of these
simulations were used to investigate a number of structural properties including the density profiles,
hydrogen bonding in polymer, and alternation in conformational properties of polymer in contact
with the surface, compared to the bulk polymer.
It is known that fluids beside solid surfaces form organized layered structures. We have observed
such layering behaviour (shown in Figure 1) for PA-6,6+nanotube system. The results indicate that
the degree of organization of the polymer beside the nanotube surface depends on the surface area
(surface curvature). Another important structural property in the present system is the hydrogen
bonding, which affects the three-dimensional structure of polymer network. The hydrogen bonds
are formed between the NH (donor) and CO (acceptor) groups in polymer. Here, we have counted
the number of hydrogen bonds in cylindrical shells (with their centers located at the center of tube)
around the nanotubes. Our results show that the hydrogen bonds are formed both within and
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between the layers. The majority of hydrogen bonds are formed between donor-acceptor pairs in
neighboring organized layers beside the surface. Our results on the number of hydrogen bonds in
close vicinity of the tube surface, as is shown in Figure 1, indicate that the chains located in such
regions are not capable of hydrogen bond formation, because of the geometrical restrictions. In
contrast, because of the formation of layered structures beside the nanotube surface, the donoracceptor groups in such layers orient properly to keep their hydrogen bond network. The maximum
numbers of hydrogen bonds are formed between the donor-acceptor groups, located in the first two
polymer layers beside the surface. The hydrogen bonding in PA-6,6 is not affected by the surfaces
at distances around 2.5 nm from the surface.
Figure 1. Density profiles for all polymer atoms (left) and number density profile for hydrogen bonds per donor (right)
as a function of distance from the nanotube surface. Both of them are normalized with the corresponding bulk value.
The legend indicates nanotube type.
References
[1] Uddin, N. M.; Capaldi, F. M.; Farouk, B. Polymer2011, 52, 288.
[2] Müller-Plathe, F. Comput. Phys. Commun. 1993, 78, 77.
[3] Eslami, H.; Müller-Plathe, F. J. Phys. Chem. B2009, 113, 5568.
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The effect of complexing agents onstructural properties of the
deposited ZnS thin films by MA-CBD method
Alireza Goudarzi a, *, Fatemeh Arab b , and Seyed Ahmad Babanejad b
a
Polymer Engineering Department, Golestan University, P.O. Box 49188-88369, Gorgan, Iran
b
Chemistry Department, Payam Noor University of Sari, Sari, Iran.
*
E-mail:[email protected]
Keywords: ZnS, Thin Film, Chemical Bath Deposition, Microwave
Introduction
Microwave assisted route is one of the novel methods and is a very rapidly developing area of
research. Compared with conventional methods, microwave synthesis requires very short reaction
time, and is capable of producing small particles with a narrow particle size distribution and high
purity [1].In this research, the effect of complexing agents on structural properties and deposition of
ZnS thin films by microwave-assisted chemical bath deposition (MA-CBD) method at low
temperature were studied.
Experimental
Zinc acetate [Zn (CH3COO) 2 .2H2O] and thioacetamide (CH3CSNH2) were used as zincand sulfur
sources respectively. Triethyleamine (TEA) and Na2EDTA were used as complexing agents. Zinc
sulfide thin films have been deposited on ordinary glass substrates by (MA-CBD) method using two
different complexing agents with power irradiation of 180 watt.
Fig.1 shows the XRD patterns obtained by scanning 2θ in the range 20–70◦.The three peaks were
observed in the diffraction patterns. These peaks can be assigned to the planes (111), (220), and
(311), respectively, of the cubic phase.
Fig.1.XRD patterns of the prepared ZnS films using two different complexing agents by MA-CBD method.
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No peaks corresponding to impurities were detected, indicating high purity of the products [1]. The
strong and sharp reflection peaks in the XRD pattern indicate that obtained ZnS films were wellcrystallized. The lattice parameter, for cubic structure was obtained from the d-interplanar spacing
of different peaks by the equation [2].
The average size (L) of the ZnS nanocrystallites
calculated using the following equation[2]:
βcos
/
(1)
and the lattice strain (η) of the film were
4 sin
(2)
When βcos θis plotted against sinθ , a straight line with slope 4ηand intercept K λ/Lis obtained, as
shown in Fig2.
a
b
Fig. 2. Plot of βcos θvs. sinθfor the prepared ZnS film by different complexing agents. (a) TEA, (b) EDTA.
The XRD peak positions, the lattice d-spacing, the lattice constants, the crystallite size and the
lattice strain of the films were listed in Table 1.
Table 1.Structural properties of the prepared ZnS thin films using two different complexing agents.
The complexing
agents
2θd-Spacing observed (hkl)
(nm)
Lattice parameter Lattice strain (%)
(nm)
Average crystallite size
(nm)
TEA
29.0997
0.3069
111
0.5315
0.023
2.62
EDTA
29.0548
0.3074
111
0.05324
0.028
2.44
Conclusion
In this study, ZnS thin films were successfully deposited on glass substrates using different
complexing agents by MA-CBD method at low temperature. The results revealed that the structures
the ZnS films deposited by MA-CBD were well crystallized and have the cubic zinc blend
structure. Furthermore, because of very small size of the ZnS nanocrystallites, the interplanar d111
and lattice parameter of the planes parallel to the film surface are less than the standard value for
the bulk ZnS powder (0.31260 nm and 0.5406 nm) respectively.
References
[1] N. Soltani, E. saion, M.Z. Hussein, and et al., Chalcogenide Letters, 9 (2012) 265.
[2]A. Goudarzi, R. Sahraei, G. M. Aval, and et al.,Thin Solid Films, 466 (2008) 488.
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The effects of Al, B, N and P-doped on electrical and sturcures of
Graphene: DFT study
M. Rezaei - Sameti, E. Samadi Jamil, A. Afrozi
[email protected]
Introduction
Since after discovery of novel nano materaial new research have been done on electrical and
structural parameters these materials and Graphene. Graphene is a flat monolayer of carbon atoms
tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for
graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into
1D nanotube or stacked into 3D graphite[1-2]. Graphene is a two-dimensional (2D) honeycombstructured lattice of carbon atoms. Graphene has dominated other organic and inorganic nanomaterials due to its flat 2-D structure and remarkable physical, thermal, electrical properties such as
zero band gap semi-metal, very high carrier mobility and mechanical toughness. The bonding is
very strong and thus graphene is highly stable. Several experimental groups have successfully
produced isolated, and room-temperature stable graphene [3–5]. In this work, we investigate the
effecs of Al, B, N and P doped on the electrical and structural properties of Graphene. For this aims,
the structural parameters involving: bond length, bond angle, HOMO, LOMU orbitals, gap of
energy, electron affinity, electronegativity and electrical chemical potential, global hardness of
Graphene are determined by performing density functional theory (DFT) using Gaussian 03
package of program.
In this work at the first time all structres of pristine and Al, B, B, and P-doped of Graphene with 39
atoms C are optimized by 6-31G** base set and B3LYP level of theory (see figure 1). The results
show that the bond lengths of C-C for equivalent positions in the all forms of Graphene are similar
(1.43 Å). By doped B, Al and P on the sites C2 the bond lengths are increased from 1.43Å to 1.77,
1.66 and 1.56Å respectively. The bond length on the N-doped is unchanged.The HOMO and
LUMO orbtals of all sturctues calculated , the comparison resutls reveal that the gap of energy
between HOMO and LUMO orbitals in pritine forms is 0.0125 and with doping of Al, B, N and P
the gap of energy is incresed.Our result show that doping of Al, B, N and P atoms on the C2 sites of
Graphene play important role on the structure of HOMO-LUMO orbitals and gap of energy
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between HOMO-LUMO, electrophilicity, electronegativity, global hardness and electronic
chemical potential. The electrophilicity, electronegativity and electronic chemical potential of Al,
B, N and P atoms doped of Graphene are decreased.
Figure 1. 2D structures of pristine and Al, B, N and P-doped on Graphene
References
[1] Y. Zhang,,Y. W.Tan, H. L. Stormer,P. Kim, P. (2005 Nature438 (7065): 201–204
[2] N.K. Jaiswal, P. Srivastav, Solid State Comm. 151 (2011) 1490–1495
[3] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov,
Science 306 (2004) 666.
[4] M.Chi, Y. Zhao, Computational Materials Science 56 (2012) 79–84
[5] J. Wintterlin, M.-L. Bocquet, Surf. Sci. 603 (2009) 1841.
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Synthesis of an organic - inorganic hybrid nanomaterial and study of
its properties in devices
Bahari Ali 1 ; Ashrafi Feridoun 2 ; Mousavi Kani Seyyedeh Nargess ٣ , *
1
Department of Physics, University of Mazandaran, Babulsar, Iran
2
3
Faculty of Science, Payame Noor University of Sari, Sari Iran
Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran, Gmail:
[email protected]
Keywords:Nano Materials, Hybrid, Anthracene, La2O3, Sol-Gel Method.
Introduction
In the recent years synthesis inorganic-organic hybrid nanomaterials have been significantly
studied. These samples have benefits organic phase (flexibility, lightweight, easy reactivity) and
also inorganic phase (high mechanical resistant, chemical and physical Stability, good optical
properties) (1) and can prevent leakage and tunneling currents through the ultra high vacuum
chamber, drug electrochemical sensors and electronic chips (2). Moreover, it can be used as a
controller gate dielectric in nano transistor's devices and memories (3).
Methods
In the present work, nanomaterials La2O3 injected with different concentration anthracene, have
synthesized with sol-gel method, and have calsinated in the temperature 3000 C and their nano
structural properties have been studied by using XRD, SEM techniques and X-powder method as
well.
Result
According to the XRD patterns and SEM images, with increasing anthracene concentration, the
La2O3 nano crystallines size have decreased and the structure of La2O3 nanoparticles became more
amorphous that because of The absence of grain boundaries can be useful for decreasing of leakage
and tunneling currents (fig 1).
Conclusion
The obtained results indicate that clacinate temperatures and molarities are key factors to achieve
optimum structure and hybrid phases. This nanomateriales can use as dielectric gate in organic
nanoeletronic devices in future and anthracene can be a good choice for research in Organic Thin
Film Transistors and Organic Field-Effect Transistors fields.
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Fig 1. XRD patterns of La2O3injected with different concentration of Anthracene (0.7, 0.14, 0.28 gr), calcinated at
temperature300 °C.
REfrence
(1) G.H. Hsiue, etal; “Microstructural and Morphological Characteristics of PS-SiO2
Nanocomposites”; Polymer, (2000) 41, 2813-2825.
(2) M. Mohseni, et al; “Synthesis and Characterization of Organic-Inorganic Hybrid
Nanocoatings and Monolithic Nanocomposites as Solid State Dye Laser Hosts”; 2nd
International Nano & Hybrid Coatings Conference, Brussels, Belgium. (2007).
(3) A. Bahari, et al; “Studying of Electrical Properties on La2O3 Nanocrystallites as for Next
NVMs Generation”; American Journal of Scientific Research, (2012) 54, 19-30.
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A computational study on the complexation of AlN nanotube with
nitrosamine
M.Zakarianejad* a , B. Makiabadi b , A. Mohammadi a , c
a
Department of Chemistry, Payame Noor University, P.O Box 19395-3697 Tehran, IRAN
b
Department of Chemical Engineering, Sirjan University of Technology, Sirjan, IRAN
c
Bandarabbas, PersianGulf Mining And Metal industries Special Zone, AlmahdiAluminiumcorp
Keywords: Nitrosamine, Aluminum nitride nanotube, Nanostructure
Introduction
Nanostructures of semiconducting materials are currently attracting a lot of interest as they are
expected to play an important role in the development of future nanoscale technologies. Many
applications of semiconductor nanomaterials to nanodevices have been demonstrated, such as
nanowire diodes [1]. Aluminum nitride (AlN) has been investigated extensively as an important
ceramic material for the applications as electrical substrates and packaging materials due to its
highest band gap (6.2 eV), excellent thermal conductivity (0.823–2.0Wcm−1 K−1), good electrical
resistance, low dielectric loss, high piezoelectric response, and ideal thermal expansion (~4×10−6
K−1) similar to that of silicon (Si) [2,3].To date, one-dimensional (1D) AlN nanostructures, such as
nanowires, nanotubes, neocons, nanotips, nanobelts, nanorods with controlled high aspect ratio,
shapes and sizes, have been investigated [4,5]. Equilibrium geometries, stabilities, and electronic
properties of nitrosamine (NH2NO) molecule adsorption on the exterior surface of single-walled
aluminum nitride nanotubes (AlNNTs) calculated.
Method
Geometry optimizations, natural bond orbital (NBO) and density of states (DOS) analyses were
performed on a zigzag AlNNT (constructed of 16 Al and 16 N atoms), and different
NH2NO/AlNNT complex configuration sat B3LYP/6-31G(d) level of theory as implemented in the
GAUSSIAN suite of program. Finally from the NH2NO functionalized AlNNT models, quantum
molecular descriptors including chemical potential (μ), global hardness (η), and electrophilicity
index (ω) were calculated. This level of theory is a popular approach which has been commonly
used for nanotube structures.
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The energy corresponding to HOMO represents the ionization potential of the molecule and the one
corresponding to LUMO determines the electron affinity value. The adsorption energy (Ead) of
NH2NO molecule has been defined as follows:
Ead= E(NH2NO /AlNNT)- E(AlNNT)- E(NH2NO)
Where E(NH2NO /AlNNT) is the total energy of complex (adsorbed NH2NO molecule on the
AlNNT surface), and E(AlNNT) and E(NH2NO) are total energies of the pristine AlNNT, and the
NH2NO molecule, respectively.
Conclusions
Results indicate that the functionalized groups cause significant changes in the electronic
properties of AlNNTs. It is predicted that the conductivity of the nanotube revolve upon
adsorption of the NH2NO radicals on the tube. Geometrical structure of the AlNNT remains
intact in the presence of oxygen molecule while its electronic structure dramatically changes so that
its HOMO (or SOMO)–LUMO gap is approximately reduced to half of its original value. Negative
values of Ead indicate exothermicity of the adsorption.
References
[1] R. Agarwal, C.M. Lieber, Appl. Phys A Mater.Sci. Process 85 (2006) 209.
[2] J.H. He, R.Y. Yang, Y.L. Chueh, L.J. Chou, L.J. Chen, Z.L.Wang, Adv. Mater. 18 (2006)
650.
[3] S.M. Bradshaw, J.L. Spicer, J. Am. Ceram. Soc. 82 (1999) 2293.
[4] Q. Wu, Z. Hu, X.Z. Wang, Y.N. Lu, X. Chen, H. Yu, Y. Chen, J. Am. Chem. Soc. 125
(2003) 10176.
[5] S.C. Shi, C.F. Chen, S. Chattopadhyay, Z.H. Lan, K.H. Chen, L.C. Chen, Adv. Funct.
Mater.15 (2005) 781.
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Photocatalytic and antibacterial effects of Ti-MCM-41 mesoporous
Majid. Mozaffari * , 1 , Fatemeh. Davardoost
1
1
,
Mehdi. Mirzaii 2 .
Department of Chemistry, Shahrood Branch, Islamic Azad University, Shahrood, Iran.
* [email protected]
2
Shahrood University of medical sciences, Shahrood, Iran.
Keywords :Mesoporous ,MCM-41,Ti-MCM-41, Antibacterial,Photocatalytic activity
Introduction
Since the discovery of MCM-41 by researchers of Mobile.Co in 1992, numerous studies have been
reported concerning synthesis mechanisms ,Preparation conditions,characterization,and application
of these materials as catalysts and catalyst supports in various reactions [1].In this study
mesoporous molecular sieve MCM-41 and Ti-MCM-41 has been synthesized Consequently
photocatalytic activity of Ti-MCM41 nanocomposite was studied in removing organic pollutant,
and antibacterial activity of the synthesized materials was investigated aginst staphylococcus aureus
and pseudomonas aeruginosa.
Methods
In this study, MCM-41 and Ti-MCM-41 mesoporous were synthesized by sol-gel method at room
temperature with molar ratios (Si/Ti)=1,10,100,1000. The samples were characterized by using
XRD, FTIR, EDX, SEM and TEM techniques.The photocatalytic activity of Ti-MCM41
nanocomposite was studied using methylene blue as a model organic pollutant and under a high
pressure mercury UV Lamp as UV light source[2].The antibacterial activity of the synthesized
materials was investigated aginst staphylococcus aureus and pseudomonas aeruginosa in
concentrations(0.05,0.1,0.5 , and 1 %) by Time kill method[3].
The crystal structure of the synthesized samples, indicated that the Ti species are highly dispersed
in the mesoporous siliceous framework.The average size of calculated nano particles by using
Debye Sherer relation have good conformity by particles size in SEM images.Fig.1 depicted the
SEM and TEM images of Ti-MCM-41 sample.Methylene blue decomposition under ultraviolet
light radiation by samples showed that by passing time concentration of this organic pigment is
decreased, so that after almost 3 hours concentration reaches zero.The antibacterial
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activitywasfound to be dependent on the molar ratio (Ti/Si).Mesoporous containing titanium in 1%
concentration showed a significant decrease in the number of colonies.
a
b
Fig .1. SEM image (a)TEM image(b)of Ti-MCM41.
Conclusion
Our findings indicate that synthesis of nano particles with completely uniform spherical
morphology
has
regular
arrangement
of
hexagonal
porous
with
regular
hexagonal
structure.Investigation of photo catalytic and antibacterial activity of nano particles showed that by
increasing the molar ratio of Ti / Si these effects increase, so that nano particles with the molar ratio
of Ti/Si =1 showed the best performance in decreasing organic pigment concentration and the
number of bacteria colonies.
References
[1]M.selvaraj ,K.S.Seshadri,Apandurangan,and T.G.Lee,Microporous Mesopourous Mater.
79,261(2005).
[2] M.S. Sadjadi, M.Mozaffari, M.Enhessari, K. Zare, Superlattices Microstruct. 47(2010) 685-694.
[3]. Shao Feng Chen , Jian Ping Li, Kun Qian, Wei Ping Xu, Yang Lu, Wei Xin Huang and Shu
Hong Yu.Nano Res (2010) 3, 244–255.
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Adsorption of Bismarck Brown by Iron Oxide Nanosphere and its
Modified Form: Equilibrium and kinetic study
Maryam Khosravi a , Bahareh Yahyaei a , Saeid Azizian * ,a
a
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan
Iran
([email protected])
Keywords: Iron Oxide, Adsorption, Bismarck Brown, Kinetic Study, Equilibrium Study
Introduction:
Recently, various type of iron oxide nanostructure have attracted wide attention because of their
wide spread applications[1]. The industrial waste water such as textile waste water contains plenty
of toxic dyes which are harmful for ecosystems and humans[2, 3]. In the present study the removal
of Bismarck Brown as a cationic dye from aqueous solution by IONs and its modified form
(MIONs) with acid have been studied from equilibrium and kinetic point of view and their
efficiencies were compared and discussed.
Iron oxide nanospheres were prepared using Fe3O4.6H2O, Polyvinylpyrrolidon, sodium acetate and
ethylene glycol and then modified by HCl.
The prepared iron oxide particles were characterized by scanning electron microscopy microscopy
(SEM), x-ray diffraction (XRD) methods, FT-IR and ATR-IR spectroscopy.
The results of this study indicate that by increasing of HCl concentration in the modification
process the efficiency of prepared adsorbent for removal of cationic dye increases. Therefore acid
modified iron oxide is efficient adsorbent for removal of cationic dye such as BB from aqueous
solution.
Kinetic data show that the rate of adsorption onto MIONs was faster than that of IONs. According
to the obtained correlation coefficients the kinetic data were best fitted with fractal-like pseudosecond order (FL-PSO) model[4].
The equilibrium shows that the MIONs have the higher adsorption capacity for the removal of BB
from aqueous solution. According to the obtained correlation coefficients, r2, the equilibrium data
of the adsorption of BB onto both adsorbents were best fitted to the Langmuir-Freundlich model.
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Conclusions
IONs and MIONs utilized as efficient adsorbents for removal of a cationic dye (Bismarck Brown)
from aqueous solution. Isotherm modeling revealed that the Langmuir–Freundlich equation could
better describe the adsorption of the BB on to the IONs and since the kinetic of BB adsorption onto
IONs and MIONs follows the fractal like-pseudo second order model, the rate coefficient of
adsorption is time dependent i.e. the adsorption path changes with time. The modification of IONs
with HCl leads to the higher adsorption capacity for BB.
References
[1]. Guardia, P.; Labarta, A.; Batlle, X.; J. Phys. Chem. C, 2011, 115, 390.
[2]. Robinson, T.; McMullan, G.; Marchant, R.; Nigam, P.; Bioresour. Technol, 2001, 77, 247.
[3]. Slokar, Y. M.; Marechal.; A. M. Le.; Dyes Pigment, 1998, 37, 335.
[4]. Haerifar, M.; Azizian, S.; J. Phys. Chem. C, 2012, 116, 13111.
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Preparation and Magnetic Properties of Nanostructured Zinc ferrite
using microemulsion method
H. Farsi 1 ,A. Amirabadizade 2 , S. Soleimanzadegan 1 , Z. Zaker 1
1
Department of Chemistry, University of Birjand, P.O. Box: 97175-615, Birjand, Iran
2
Physics Department, University of Birjand, P.O. Box: 97175-615, Birjand, Iran
Keywords: Nanostructure, Zinc ferrite, Reverse micelle, Microemulsion, Mixed surfactant
Introduction
Nanomaterials represent a novel class of materials with physical and chemical properties that are
different from those of the bulk material. Due to the small dimensions of nanocrystals, an important
fraction of the atoms is on the surface, which induces properties that are different from
polycrystalline material obtained through conventional methods. Reverse micelles, which are
essentially nanosized aqueous droplets that exist in microemulsions with certain compositions, are
known to represent an excellent medium for the synthesis of nanoparticles with uniform
morphologies. By varying different parameters within a given microemulsion system, such as the
concentrations or the molar ratios of constitutive components, for instance molar ratio of water to
surfactant, w 
[ water ]
, it is said to be possible to design the structure, the properties and
[ surfac tan t ]
therefore the applications of a synthesized products [1-4]. Surfactant type and the ration water to
surfactant are the most important factor in microemulsion systems.
In this study, Triton X-100 and sodium dodecyl sulfate, SDS, and their 1:1 mixture and
cethyltrimethyl ammonium bromide, CTAB, as surfactants, normal heptanes as oil phase and
normal pentanol as cosurfactant were used for preparing the reverse micelles and microemulsion
which are used to prepare zinc ferrite nanoparticles.
Materials and Methods
Zn(NO3)2, Fe2(NO3)3, Triton X-100, SDS, CTAB, n-heptan and n-pentanol purchased from Merck
company and used without further purification. Some microemulsions with different compositions
and surfactants including w=10, w=16 and w=18 with SDS and w=16 with a 50:50 mixture of
SDS+CTAB and SDS+Triton X-100 were prepared. The aqueous phase, w, was containing a molar
ratio of 1:2 for Zn:Fe. The appropriate amount of NaOH was added to prepared microemulsion to
convert the free cations to hydroxide. The hydroxide precursors were calcined at 550ºC to form
ZnFe2O4. The crystal structure and morphology of prepared ferrites were verified by XRD-pattern
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analysis and TEM, respectively. Finally vibrating sample magnetometric, VSM, analysis is used for
studying the magnetic properties of prepared ferrites.
Result and Discussions
XRD-pattern analysis illustrated a cubic spinel crystal structure for calcined ferrites with a
crystallite size 6-10 nm calculated using Scherrer’s equation.
TEM monographs showed the
spherical nanoparticles with a size of 10-50 nm regards to w values, i.e. by increasing in w value the
nanoparticles size raises, too. Furthermore, the magnetic properties of prepared ferrites were
depended not only to the molar water to surfactant ratio but also to the surfactant and mixed
surfactants, as shown in figure 1.
w=10 SDS
w=16 SDS
8
w=18 SDS
Moment/Mass(emu/g)
Moment/Mass(emu/g)
10
0
w=16 SDS+CTAB
w=16 SDS+Triton X-100
w=10 SDS
w=16 SDS
w=18 SDS
0
-10
-8
-20000
0
20000
-20000
Field(G)
0
20000
Field(G)
Figure 2: Hysteresis loops at room temperature for prepared nanostructure with different w values and mixed
surfactants, calcintaed at 550˚C.
Conclusions
The dimensions and magnetic properties of the zinc ferrite nanoparticles calcined at 550ºC were
smaller than 50 nm, depending on molar ration of water to surfactant and the type of surfactant used
in microemulsion.
References
[1] V. Uskoković, M. Drofenik, Adv.Colloid Interface Sci. 133 (2007) 23–34.
[2] C. Manohar, J. Narayanan, Colloids and Surfaces A: Physicochem. Eng. Aspects 403 (2012)
129– 132.
[3] C. Yang, Q. Wang, C. Yi, J. Zhao, J. Fang, W. Shen, J. Electroanal. Chem. 674 (2012) 30–37
[4] V. Uskokovic´, M. Drofenik, I. Ban, J. Magn.Magn. Mater. 284 (2004) 294–302
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Production And Characterization Of Austenitic Nanocomposites On
Ultra High Vacuum
B.Tahmasbpour * a and A.Bahari b
a
Department of Physics, University of Payam noor Tehran, Parand
([email protected])
b
Department of Physics, Mazandaran University, Babolsar
Abstract
Nanocomposite austenitic synthesized by the sol- gel method. The materials used for the synthesis
were: Fe(NO3)3 9H2O, Ni(NO3)2 6H2O, Zn(NO3)2 6H2O, ethylene glycol ,Tetra Ethyl Ortho
Silicate(TEOS), ethanol(C2H5OH) . The morphologies and topographies of the samples synthesized
have been studied with using Scanning Electron Microscopy (SEM) and X-Ray diffraction (XRD)
Techniques.
Keyword: Austenitic, sol- gel, Ultra High Vacuum, X-Ray Diffraction, Scanning Electron
Microscopy.
Introduction
We need to study austenitic stainless steel (ASS) properties, because the higher stability of ultra
high vacuum (UHV) chamber is needed for growing the ultra thin film, like silicon nitride and me
metallic, oxide films. To grow an ultra thin oxide film we need a UHV chamber which can keep
low pressure down to 10-14 Torr. The current UHV chamber can not keep such a low pressure due to
leakage and some unwanted bonds on the SS structures. The principal aim is the nanostructural
evolution of this samples.
Discusion and Results
The materials used for the synthesis were:
Fe(NO3)3,9H2O (Merck), Ni(NO3)2, 6H2O (Merck), Zn(NO3)2, 6H2O (Merck), ethylene glycol
(p.a.), 15 mm ethanol (C2H5OH) and 25 mm Tetra Ethyl Ortho Silicate(TEOS) (Fluka,98%).
In the first experiment: The molar ratio of Fe nitrate to Zn and Ni nitrates were 8 , 2.2
respectively.
In second experiment: The molar ratio of
Fe nitrate to Zn and Ni nitrates were 8 , 1.4
respectively.
The metallic nitrates, weighed to the designed stoichiometric ratio, have been dissolved in
ethyleneglycol and ethanol. The obtained solution has been slowly added in drops, while stirring,
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to the ethanol TEOS solution. Ethanol has been added in order to increase the miscibility of the
two solutions.
The homogenous, clear solutions obtained in this syntheses were subordinate to stirring at room
temperature and air atmosphere to gellify. After 24h stirring, the sol was transmuted to gel.
The obtained gels have been dried in the drying oven at80ºC, for 15 minutes. After drying and
milling, the resulted powders have been thermally treated at different temperatures and than
characterized. In picture 1,2 it let to crystallization structure at 700 °C.As Shown in picture 2,
peaks located at 35°, 43°, 50°, 63° and 75° attributed to the (111), (200), (440) and (220)
diffraction plans of the face center cubic (FCC). Compractive samples show that the second
exprimental is going to be amorphous.
Picture 1: XRD patterns of firstexprimental at 700 °c
Picture 2: XRD patterns of of secondexprimental 700 °c
picture(3) represented the SEM images of samples austenitic synthesize
at 700 °C ,
900°Ccalcinated temperature. The reason is that scherrer equation can be only used for spherical
particle. Compractive samples show, the temprature increases and Ni particles the rate of cavities
and cracks are reduct wich may indicate leakage flow into the chamber is reduced.
a
c
b
Picture 3:SEM Images of sample (a) in first experiment at 700°C , (b,c) in second experiment at
Conclusions
The obtained results indicate that adding Ni particle into stainless steal matrix, modified stainless
steal mechanical structures.
Refrences
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[1] D.A. Buchanan and S.H. Lo, "Growth, Characterization and the Limits of Ultrathin SiO2 Based
Dielectrics for Future CMOS Applications", Electrochemical Society, 75 (1996), 3.
[2] A. A. Lebedev 1 and V. V. kosarchuk 2, "influence of phuse transformations in the mechanical
properties of austenitic stainless steel", intemational journal of plasticity, vol. 16(2000), pp. 749767.
[3] A. Bahari, P. Morgen, K. PedersonJournal Vacuum, Science and Technology,(2006), pp. 21192123. Canada.
[4] A. Bahari, P. Morgen, Z.S. Li, Surface Science. (2006), 600, 2966-2971.
[5] P. Morgen, A. Bahari, M.G. Rao and Z.S. Li., Journal Vacuum and Technology A. (2005), 23:
201-07.
[6] M.Pashaeiyan, A. Bahari, Nano Structural properties of stainless steel for ultra high vacuum
chambers.(2011), pp:403-407.
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A Molecular Dynamics Study On Melting Of Carbon NanotubeSupported Silver Nanoclusters
Hamed Akbarzadeh a , Hamzeh Yaghoubi * a
a
Department of Chemistry, Faculty of Basic Sciences, Hakim Sabzevari University, 96179- 76487Sabzevar, Iran
([email protected])
Keywords: Molecular dynamics, Silver nanoclusters, Nanotube-supported, Melting, Structural
change, Sutton-Chen potential
Introduction
Metallic nanoclusters supported on substrate have been drawn much attention to themselves, and
gain more industrial applications such as heterogeneous catalysis, sensors and microelectronics.
Because the large surface area to volume ratio of nanoparticles can bring out unique physical,
chemical and electronic properties than the bulk materials and isolated atoms.A relation between
the radius of nanoparticles and melting point was first founded by Pawlow at 1909 [1], and the first
experimental investigation of melting point dependence on particle size was conducted more than
50 years ago [2]. Recently, researchers have been applied theoretical and experimental methods to
investigation the thermal, structural and dynamics properties of free and supported nanoclusters
[3,4]. Nanoclusters melt at temperature below the melting point of bulk materials and this
temperature decreases with the cluster size. The reason of this phenomenon related to increment the
fraction of the surface atoms whereas the cluster size decreases.
Simulation details and methods
The MD simulations were carried out by DL_POLY 2.18 program in canonical ensemble (NVT)
with periodic boundary conditions in
and
directions. The equations of motion were integrated
using the Verlet leapfrog algorithm with a time step of 1 fs. For kept temperature in constant value
the Berendsen thermostat with a relaxation time of 0.01 ps was applied. Three silver nanoclusters
contain 38, 108, and 256 atoms placed on a nanotube with 800 carbon atoms. Systems were
simulated in heating and cooling processes at the 100-1700K temperature range with steps of 100K.
The many body quantum Sutton-Chen (QSC) [5] and two body Lennard-Jones (LJ) potentials were
used for metal-metal and rest interactions, respectively.
The melting point of nanoclusters were defined by potential curves and heat capacity, also
confirmed by deformation parameters, and diffusivity of them. Results show that the melting points
of nanoclusters are much below the bulk silver melting point that is 1234.93K. So, the nanocluster
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melting point decreases with decreasing size, due to the much larger surface to volume atoms ratio
in clusters than bulk materials, and this ratio extremely increases when the cluster size decreases.
nanocluster, which is 680K, and also the
Figure 1 (a) illustrates the melting point of
hysteresis in the course of the cooling process. Figure 1 (b) shows the deformation parameters of
nanocluster in three directions that is confirmed the melting point and structural change with
temperature.
(a)
-280
(b) 7
-316
x
-318
-290
-322
-300
5
-324
-310
-326
500
550
600
650
700
750
800
850

Energy (eV)
y
z
6
-320
4
-320
3
-330
-340
2
heating process
cooling process
-350
1
0
200
400
600
800
1000
1200
1400
1600
1800
0
200
400
600
800
1000
1200
1400
1600
1800
T (K)
T (K)
Figure 1. (a): The potential curves of heating and cooling processes for
heating process with steps of 20K. (b): Deformation parameters
nanocluster, inset the potential curves of
in all directions for
nanocluster.
Deformation parameters and RDF were employed to investigation the structural changes with
temperature. In temperature above the melting point, the cluster was flattened on substrate and
rolled up around the nanotube and surface wetting occurs. When cluster cooled, the cluster layer in
contact with substrate protected the interface structure, because in this layer the silver atoms located
on middle of aromatic rings of carbon nanotube and have best interactions with carbon atoms. Also,
at temperature below the melting point the MSD and diffusivity of nanocluster in cooling process
are a few smaller than heating process.
References
[1] P. Pawlow, Z. Phys. Chem. 65 (1909) 1.
[2] M. Takagi, J. Phys. Soc. Jpn. 9 (1954) 359.
[3] Z. M. Ao, W. T Zheng and Q. Jiang, Nanotechnology 18 (2007) 255706.
[4] W. H. Luo, W. Y. Hu, S. F. Xiao, J. Phys. Chem. C 112 (2008) 2359.
[5] A.P. Sutton and J. Chen, Philos. Mag. Lett. 61(1990) 139.
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Gas Adsorption On Silver Nanoclusters Supported On A Carbon
Nanotube Surface
Hamed Akbarzadeh a , Hamzeh Yaghoubi * a
a
Department of Chemistry, Faculty of Basic Sciences, Hakim Sabzevari University, 96179- 76487Sabzevar, Iran
([email protected])
Keywords: Molecular Dynamics Simulation, Gas Adsorption, Silver Nanoclusters, Carbon
Nanotube, Irreversible Changes.
Introduction
Metallic nanoclusters deposited on substrate surface have been gained more industrial applications
such as heterogeneous catalysis, sensors, and microelectronics. Because, they have unique
chemical, physical, electronic, and optical properties owing to their large fraction of surface atoms.
Gas phases have important effects on the nanocluster structure, because the gas atoms adsorb on
nanocluster surface, and it well known that the nanoclusters have the large ratio of surface to
interior atoms. Gas phase effects on substrate-supported nanoclusters have been studied in more
theoretical and experimental methods [1,2].
Molecular dynamics simulations were performed on canonical ensemble (NVT) with constant
atoms number N, volume V, and temperature T, which temperature was kept in constant value by
Berendsen thermostat with a relaxation time of 0.01 ps. The equations of motion were integrated
using the Verlet leapfrog algorithm [3] with a time step of 1 fs. The many body quantum SuttonChen (QSC) potential [4] was applied to describe the Ag-Ag interactions. So, the Lennard-Jones
(LJ) 12-6 potential was employed for rest interactions. Five gas atmospheres (He, Ar, Xe,
, and
CO) in cubic box with periodic boundary conditions in all directions were added on carbon
nanotube-supported silver nanoclusters contain 38, 108, and 256 silver atoms. Each of systems were
simulated at various conditions of pressure and temperature.
The gas atoms were adsorbed on nanocluster surface at constant temperature as adsorption
isotherms of Langmuir type I. Figure 1 (a) shows the adsorption isotherms of all gases for
nanocluster at 300K. In the adsorption isotherms, the number of adsorbed gas atoms increases to a
constant value when the pressure increases. Because the nanocluster surface covers by one layer of
gas atoms. The gas that has large atom and large values of Lennard-Jones parameters receives to a
constant value of adsorbed atoms in low pressure than others. The adsorption decreases with
increasing temperature, and tends to a constant value at temperatures environs the melting point of
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nanocluster. About the nanocluster size, the nanocluster with small size has the greater adsorbed gas
atoms to total atoms of nanocluster ratio than large nanocluster, owing to its greater fraction of
surface atoms. It found that the several small nanoclusters instead of the one large nanocluster can
adsorb larger amount of gas atoms. Moreover, the gas phase affects on nanocluster structure and
causes the nanocluster layer in contact with substrate become to expand, and this structural change
is irreversible, when the gas phase gradually disappears. Finally, the gas phase increases the
nanocluster diffusion, specifically at low temperatures and high pressures. Figure 1 (b) illustrates
the MSD of
nanocluster in vacuum and in the presence of different gases at 300K. At high
temperatures the difference between nanocluster diffusion in the vacuum and in the presence of
gases become to reduce. At a constant temperature, when the gas pressure decreases to the vacuum,
at first, the nanocluster diffusion strongly decreases and then gradually tends to its value in vacuum.
(a)
(b)
140
80
vacuum
400 He
400 Ar
400 Xe
400 H2
400 CO
60
100
He
Ar
Xe
H2
CO
80
60
MSD (A2)
Number of adsorbed atoms
120
40
40
20
20
0
0
20
40
60
80
100
120
0
50
100
150
time (ps)
Pressure (atm)
Figure 1. Adsorption isotherms of gases for
nanocluster at 300K (a), and MSD of
nanocluster in vacuum
and in the presence of different gases (b).
References
[1] K. Hojrup Hansen, Z. Sljivancanin, E. Lgsgaard, F. Besenbacher, I. Stensgaard, Sur. Sci. 505
(2002) 25–38.
[2] G.-W. Wu and K.-Y. Chan, J. Electroanalytical Chem. 450 (1998) 225–231.
[3] M. P. Allen and D. J. Tildesley, Computer Simulation of Liquids (Oxford University Press,
1987).
[4] A.P. Sutton and J. Chen, Philos. Mag. Lett. 61(1990) 139.
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Conference
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Detecting Low-Concentrations of Ammonia Using Reduced Graphene
Oxide Gas Sensor
M. Ghezellou* a , H. Haratizadeh a , O. Malekan a
Department of Physics, Shahrood University of Technology, University Blvd., Shahrood, Iran
([email protected])
Keywords: Graphene Nanosheets, XRD, SEM, Ammonia, Sensor Device
Introduction
Ammonia is a flammable, toxic and colorless gas, though monitoring PPMs of that is a challenge
for human health care and property protection. To the flammability, detecting of this gas at room
temperature (RT) is so important. Graphene with mono layer sp2 bounded carbon atoms, has a
specific electronic properties.[1] Graphene based gas sensors has been attracted many researches
around the world in recent years because of their operating at RT. We fabricated a simple, cheap
and RT operating sensor device for NH3 detection. The sensor device has been studied for exposing
to NH3 Gas. The results showed very fast response to low-concentrations of Ammonia gas.
Graphite oxide solution was obtained through modified Hummers method by using of natural
graphite powder as starting material.[2] The obtained solution was bright yellow in color. The
solution was centrifuged and washed by warm diluted HCl and dried at 40
for 24 hours. Then by
the mean of ultrasonication the graphite oxide was turned to GO. The sensing device was fabricated
by drop-casting of aqueous solution onto pre interdigitated electrode-deposited alumina substrate.
X-Ray Diffraction (XRD)and Scanning Electron Microscopy (SEM)has been used to characterize
the structural and morphological properties of prepared layers respectively.
Gas sensing measurements was done by using of self-designed set up. The mechanism of tests was
measuring the change in resistivity when device was exposed to target gas.
XRD pattern Fig [1] proved that nearly amorphous structure of GNSs was produced. As the SEM
images show in Fig [2], GNSs are created.
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Lin (Counts)
400
300
200
100
0
10
20
30
40
50
60
7
2-Theta - Scale
Fig 2. SEM images of GNSs
Fig 1. XRD pattern of GNSs
When GNSs thin film as an active layer exposes to target gas, the molecules of the gas adsorb with
the surface of the layers and the electron transform occurs between GNSs and gas molecules. The
behavior of GNSs is similar to p-type semiconductor [3] and when it was exposed to target gases its
gas that is reducer or oxidizer respectively. The
sensitivity was calculated using the expression below:
SG = [(RGas – RBaseline) / RBaseline] × 100.
RBaseline is resistivity of the active layer being exposed
Sensitivity (%)
resistivity decreases or increases with regard to the
to nitrogen gas. Response time has got on 30 sec and
the recovery time on 45 sec. It has understood from
these data that the greatest recovery time is due to low
6
5
4
3
2
1
0
‐1 0
500
1000
1500
2000
Time (s)
Fig 3. Sensitivity of fabricated device to
2000 ppm NH3 Gas
temperature of reaction and subsequently it causes to need
more time to removing the gas from chamber. The amount of Ammonia injected to the chamber
was calculated by weighting the amount of pure gas in a syringe and it was obtained as 2000 ppm.
Conclusion
Graphene nanosheets has been synthesized successfully and the sensing device was fabricated.
Ourcheap and simple fabricated device promises very high capabilities for graphene based sensors.
References
[1]. Wei Gao; Lawrence B. Alemany; Lijie Ci; Pulickel M. Ajayan., Nat. Chem,2009, 10, 1038
[2]. Jiali, Z.; Haijun, Y.; Guangxia, S.; Ping, C.; Jingyan, Z.; Shouwu, G.; Chem. Commun, 2010,
46
[3]. Ganhua Lu; Leonidas E. Ocola; Junhong Chen; Nanotechnology,2009, 20, 44
1131
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Conference
‫ه ﯽ‬
Synthesis and Characterization of Graphene Nano-Sheet films
M. Ghezellou* a , H. Haratizadeh a , Z. Mohammadian a
Department of Physics, Shahrood University of Technology, University Blvd., Shahrood, Iran
([email protected])
Keywords: Graphene Nano-sheets, XRD, SEM, Raman, Hummers Method
Introduction
Graphene is an exciting material.[1] This material with monolayer sp2 bounded atoms has many
specific properties. Its optical transparency beside its hardness as well as its high electron mobility
marked it as fascinating material ever known. Synthesis of graphene films could done by numerous
methods but the simple inexpensive one is synthesis through Hummers method. In this this study
Graphene Nano-sheets (GNSs) were synthesized successfully through Hummers method and typical
analysis like Optical Microscopy, Scanning Electron Microscopy, X-Ray Diffraction and Raman
Spectroscopy have been investigated for proving whether they’re created or not and if yes, what is
the characteristics of as prepared layers.
Initially, ball-milled natural graphite powder and sodium nitrate were putted in 250 ml flask. Then
50 ml of H2SO4 was added. Temperature of flask has been kept on 0
by using of an ice bath.
During the process flask and bath were on magnetic stirrer. After 2 hours KMnO4 was added slowly
to the solution and the temperature was prevented to exceed from 10 . After adding KMnO4 the
temperature was raised to 35
and stirred for another 2 hours. After completion of the reaction, 90
ml of water was poured slowly into the solution under vigorous stirring, and dark brown suspension
was obtained. The suspension was treated further by adding a mixture of H2O2 and distilled water to
convert residual permanganate and MnO2 into soluble MnSO4. The obtained solution was bright
yellow in color. The graphite oxide powder was separated from the mixture by centrifugation and
was washed by warm diluted HCl and finally was dried at 40
for 24 hours.The resulting graphite
oxide was turned into GO by ultrasonication at room temperature for 4 hour.[2] Afterward GNSs
film was formed by drop-casting of solution on 300
alumina/quartz substrate. In fact changing of
GO into Reduced Graphene Oxide (RGO) was due to thermal reduction of GO suspension.
X-Ray Diffraction (XRD),Scanning Electron Microscopy (SEM) and Raman Spectroscopy was used
to characterize the structural and morphological properties of prepared layers.
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XRD pattern proved that nearly amorphous structure of GNSs were produced and although it shows
the effect of reduction of graphene oxide on its spectrum. As we see in Fig [1a] there are two peaks
with one sharp and the other wide peak that are relate to GO and RGO respectively. But in Fig [1b]
400
a
Lin (Counts)
500
400
300
Lin (Counts)
600
b
300
200
200
100
100
0
0
10
20
30
40
50
60
7
10
20
30
40
50
60
7
2-Theta - Scale
2-Theta - Scale
Fig 1. XRD spectrum of (a) partially reduced graphene
Fig 2. SEM images of graphene oxide Nano-sheets.
oxide and (b) reduced graphene oxide.
we cannot see the sharp one anymore and this is due to fully reduction of GO.
As the SEM images show in Fig [2], GNSs are created but it can’t help us to determine the number
of layers. For being insure from formation of few layer GNSs Raman Spectroscopy is needed. The
2D peak at ~2687 cm-1 of the spectra proves the formation of few layer GNSs. The number of
layers are related to FWHM of the 2D peak.[3] D peak and G peak are relates to defects in graphene
and sp2 bounds relatively. Another peak, which is the D+D′ band (2954 cm-1) is the combination of
phonons with different momenta around Κ and Γ.[4]
Conclusion
Graphene Nano-sheets were synthesized successfully through Hummers Method; and SEM
pictures, XRD spectra and the 2D peak in Raman spectroscopy proves our assertion.
D
1373
Intensity (a.u.)
G
1608
D+D'
2687
2954
2D
500
1000
1500
2000
2500
3000
Shift (cm
Fig4.RamanRaman
spectra
of) graphene
-1
oxide Nano-sheets.
References
1133
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Conference
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[1]. Geim, A.K.; Novoselov, K.S.; Nat. Mater, 2007, 6, 183
[2]. Jiali, Z.; Haijun, Y.; Guangxia, S.; Ping, C.; Jingyan, Z.; Shouwu, G.; Chem. Commun, 2010,
46
[3].Ferrari, A.C.; Meyer, J.C.; Scardachi, V.; Casiraghi, C.; Lazzeri, M.; Mauri, F.; Piscanec, S.;
Jiang, D.; Novoselov, K.S.; Roth, S.; Geim, A.K.; Physical Review Letters, 2006, 97, 187401-1
[4]. Iqbal, M.W.; Singh, A.K.; Iqbal, M.Z.; Eom, J.; J. Phys.: Condens. Matter, 2007, 24, 335301
1134
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
Influence of SnO 2 Molar Ratio on the Band Gap Energy of TiO 2 /SnO 2
Thin Films
M. Taheri Emami * a , H. Milani Moghaddam a ,b
a
b
Department of Physics, University of Mazandaran, Babolsar
Nano and Biotechnology Research Group, University of Mazandaran, Babolsar
Keywords: Thin Film, Sol-gel, Band Gap, TiO2/SnO2
In this research, we prepared TiO2 thin films with different molar ratios of Sn on slide glass
substrate using Spin Coating process. After annealing the samples, we studied the surface
morphology by Scanning Electron Microscope (SEM, S-4160 model at 15 kV). To determine the
optical energyband gap,we also measured the absorption and transmission spectra by
spectrophotometer (UV-vis, PG Instrument-T80+ type).
In recent years the use of nanoparticles and thin films has been very widely expanding due to
different applications in the fields of electronic, optical, metallurgical and biomedical engineering
and etc. TiO2 thin film can be photoexcited by UV light irradiation which is only about 2-4% of
sunlight [1]. Therefore, an increase of the optical absorption of TiO2 in the visible region to
improve its visible response is desired. Doping of TiO2 with metal oxides such as Al, Mn, Zn and
Sn is especially beneficial for an enhancement of visible light activity of TiO2 [2].
For preparing the SnO2 doped TiO2 thin films, Titanium tetra-isopropoxide(TTIP) and SnCl4.5H2O
were firstly dissolved in ethanol, stirred at room temperature for 30 min. pH of the mixed solution
was adjusted to 7.5 with 2M Ammonia. Then, distilled water was added to the solution, stirred for
15 min. The mole ratio of TTIP:C2H5OH:H2O was 1:75:3 and the mole ratio of SnO2 to TiO2 were
2,3,5,7 mol%. The prepared solution transparent sol was kept at room temperature for 7h before
coating on a clean soda lime glass substrate using spin coating at a speed of 3000 rpm for 40
seconds. Films were dried and then annealed at 80 0C and 450 0C for 2h, respectively.
Figure 1 shows transmission spectra of SnO2 doped TiO2 thin films. Figure 2 shows SEM image of
3 mol% SnO2 doped TiO2 thin film. We calculated the optical band gap energy of SnO2 doped TiO2
thin films using the Kubelka-Munk theory (Figures 3 and 4) [3].
Our results indicate that the minimum transmission spectra of TiO2 thin films are related to
impurities doped with 5 mol% Sn and 3000 rpm coating speed. and energy band gap increesed with
increase SnO2 doped TiO2 thin films.
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Transmittance(%)
100
50
SnO2:TiO2=2 mol%
0
SnO2:TiO2=3 mol%
SnO2:TiO2=5 mol%
SnO2:TiO2=7 mol%
300
400
500
600
700
800
Wavelength (nm)
Figure 1: transmission spectra of SnO2 doped TiO2
Figure 2: SEM image of 3 mol% SnO2 doped TiO2
thin films
thin film
8
SnO2:TiO2=2 mol%
7
SnO2:TiO2=3 mol%
SnO2:TiO2=5 mol%
SnO2:TiO2=7 mol%
6
400
300
250
(h)2
h

5
4
3
200
150
2
100
1
50
0
3.75
SnO2:TiO2=2 mol%
SnO2:TiO2=3 mol%
SnO2:TiO2=5 mol%
SnO2:TiO2=7 mol%
350
4.00
h (eV)
0
4.25
4.0
h(ev)
Figure 4: Band-gap energies of SnO2 doped TiO2 thin
Figure 3: Band-gap energies of SnO2 doped TiO2
films for direct allowed transitions
thin films for indirect allowed transitions
References
[1] S. Mozia, K. Bubacz, M. Janus, A. W. Morawski, “J. Hazard. Maters”, 203 (2012) 128.
[2] B. Pal, T. Hata, K. Goto, G. Nogami, “J. Mol. Catal. A Chem”, 169 (2001) 147–155.
[3] H. Lin, C. P. Huang, W. Li, s. Ni, S. Ismat shah, Y. H. Tseng , “Appl. catal. B-Envairon”,68
(2006) 6.
1136
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
Isotherm and kinetic studies on the adsorption of papain nanoparticle
by ion-exchange adsorbents
H. Nasrollahzadeh a,b , M. Jahanshahi b * , S.A. Manafi a
a. Department of Engineering, Shahroud Branch, Islamic Azad University, Shahroud, Iran
b. Nanotechnology Reasearch Institute, Faculty of Chemical Engineering, Babol University of Technology, Babol, Iran
([email protected]; [email protected])
Keywords:Papain nanoparticle, Adsorption, Isotherm, Kinetic, Ion-exchange adsorbents.
Abstract
While nanobiotechnology is developing worldwide for establishing sustainable life, using protein
nanoparticle is also helpful for biological applications. However several biodegradable
nanoparticles of natural polymers such as starch, chitosan, gelatin and albumin are extremely in use
as carriers in biological applications, papain nanoparticles represent a promising candidate for drug
delivery and food science application [1,2]. Papain is a cysteine endopeptidase obtained from
Carica papaya Linn [3]. Modeling of the adsorption equilibrium data is vital for a reasonable plan,
scale-up, and improvement of downstream processes, in order to predict the concentration profile
along the expanded bed adsorption column for industrial or preparative purification applications [4].
The objectives of this study are to establish kinetic and isotherm models those better described the
adsorption of papain nanoparticle by the streamline DEAE adsorbents. The research work was
carried out during 2011-2012 in the Nanotechnology Research Centre, Faculty of Chemical
Engineering, Noshirvani University of Technology, Babol, Iran.During this analysis, fabrication of
papain nanoparticle by simple coacervation method was carried out [2]. All adsorption experiments
were carried out by using a batch process by mixing 1 mL of streamline DEAE with 10 mL of
papain nanoparticle solution over the concentration ranges of 0.5 to 2 mg mL-1, in glass vials. The
mixtures were agitated at a speed of 110 rpm on a shaking incubator. Samples were taken at certain
time intervals. The concentration of papain nanoparticle was measured by spectrophotometry at the
wavelength of 280 nm. Each experiment was performed at least twice. The adsorption kinetics were
analyzed using pseudo-first-order and pseudo-second-order models.The results depicted that
regression correlation coefficients (R2) values for the pseudo-second-order model are much higher
than those for pseudo-first-order kinetic. This suggests that the adsorption of papain nanoparticle on
streamline DEAE adsorbents follow the second-order kinetics. Modeling of the equilibrium data
performedusing the Langmuir and Freundlich isotherms.The adsorption isotherm experimental data
obtained at different concentrations of the papain nanoparticle solution were fitted with Langmuir
and Freundlich isotherm models.The isotherms fitting results demonstratedthat the Langmuir
1137
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isotherm model fitted the equilibrium data slightly better than the Freundlich isotherm model. This
research showed that the streamline DEAEcan be a suitable candidate as an ion-exchange adsorbent
in the separation of papain nanoparticle from biological fluids.To the best of our knowledge, this
study is the first to estimate the isotherms and kinetics of papain nanoparticle adsorption on the ionexchange adsorbents and deserves further study.
References
[1] M. Jahanshahi, M. Sanati, S. Hajizadeh, Z. Babaei, Gelatin nanoparticle fabrication and
optimization of the particle size, physica status solidi (a), 205 (2008) 2898-2902.
[2] H. Nasrollahzadeh,M. Jahanshahi, S. Manafi, M. Nasrollahzadeh, Fabrication of Papain
Nanoparticles as a Potential Candidate for Drug Delivery and Food Science Application,
(2012), The 14thIranian National Chemical Engineering Congress (IChEC 2012), Sharif University
of Technology, Tehran, Iran.
[3] T.-X. Chen, H.-L. Nie, S.-B. Li, C. Branford-White, S.-N. Su, L.-M. Zhu, Comparison:
adsorption of papain using immobilized dye ligands on affinity membranes, Colloids and Surfaces
B: Biointerfaces, 72 (2009) 25-31.
[4] F.Bautista, M. Martinez, J. Aracil, Adsorption Equilibrium of α -Amylase in Aqueous Solutions,
45 (1999) 761-768.
1138
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
Investigation of nano-structured polythiophene morphology by changing the
molar ratio of reagents
M. Nasrollahzadeh a,b , M. Jahanshahi b * , M. Salehi a , M. Behzad a , H. Nasrollahzadeh c, b
a. Department of Chemistry, Semnan University, Semnan, Iran
b. Nanotechnology Reasearch Institute, Faculty of Chemical Engineering, Babol University of Technology, Babol, Iran
([email protected]; [email protected])
c. Department of Engineering, Shahroud Branch, Islamic Azad University, Shahroud, Iran
Keywords:nano-structured polythiophene, modifying, chemical structure, morphology,
polymerization yield.
Abstract
The emergence of nanotechnology over the past few years has had an immediate influence on
various aspects of technologies.Nanostructured materials have attracted great research interest and
the technology of their production and use is rapidly growing into a powerful industry
[1,2].Conducting polymer nanostructures are a group of nanostructured materials withalsohaving
unique properties such as solubility, long term stability of the electrical conductivity, general
chemical and thermal stability, mobility and others, have the characteristics of nanomaterials (e.g.
large surface area, size, and quantum effect) that introduced them as a promising candidate for
various industrial applications[3]. The fabrication of nanoparticles of controlled size, shape, and
functionality is a key challenge in nanotechnology. On account of the ordinary synthesis of
conducting polymers handles a polymer with unpredictable morphology, nanotechnology inquiries
a route to control the bulk polymer properties. At the present time, there are variant systems to
synthesis conducting polymer nanostructures [4].Right around countless engaging conducting
polymers that have been developed over the past 25 years such as polyanilines, polypyrroles and
polyphenylenes, Polythiophene has been quite compelling because of its elevated electrical
conductivity, improved mechanical properties, elevated charge transporter portability and different
suitable headlines [5]. The research work was carried out during 2011-2012 in the Nanotechnology
Research Centre, Faculty of Chemical Engineering, Noshirvani University of Technology, Babol,
Iran.Nano-structured polythiophene was synthesised by combining of sodium dodecyl sulfate
(SDS) as an anionic surfactant, triethanolamine (TEA) as a co-surfactant and ammonium persulfate
(APS) as an oxidant in aqueous medium. Surfactants are amphiphilic and a fundamental property of
surfactants is that they tend to aggregates in solution, so-called micelle. Micelle acts as a
nanoreactor. The prepared micelles fill in as engaging media for polymerization reactions after
expansion of oxidizing agent. Additionally, the morphology of the nanostructured polythiophene
1139
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was regulated by modifying the molar degree of oxidant, surfactant and co-surfactant. The chemical
structure of nano-structured polythiophene was considered by Fourier Transform Infrared (FTIR)
spectroscopy. The morphology of the products were examined by Scaning Electron Microscope
(SEM) and the polymerization yield of productswere calculated. It was found that by increasing the
co-surfactant, the morphology of the products changed to ribbon. In view of characterization plans,
the development of nano-structured polythiophene was affirmed.
References
[1] P.M. Ajayan, L.S. Schadler, P.V. Braun, Nanocomposite science and technology, Wiley. com,
2006.
[2] H.S. Nalwa, Nanostructured materials and nanotechnology: concise edition, Gulf Professional
Publishing, 2001.
[3] L. Xia, Z. Wei, M. Wan, Conducting polymer nanostructures and their application in biosensors,
Journal of colloid and interface science, 341 (2010) 1-11.
[4] J. Jang, Conducting polymer nanomaterials and their applications, in: Emissive Materials
Nanomaterials, Springer, 2006, pp. 189-260.
[5] G. Schopf, G. Kossmehl, Polythiophenes-Electrically conductive polymers-Introduction,
Polythiophenes-Electrically Conductive Polymers, 129 (1997) 3-145.
1140
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
Investigation of Immobilized Silver Nanoparticles –catalyzed Oxidative in
Eliminating Trace Azo Dye with Peroxydisulfate from Contaminated water
M. Shahgholi
a
b
*a
, M. H. Rasoulifard b and J. Khamesi c
Department of Chemistry & Environment,University of Zanjan ( [email protected])
Department of Chemistry & Environment , University of Zanjan , Iran. ([email protected])
c
Department of Environment Protection , Zanjan Province. ([email protected])
Keywords: advanced oxidation, Nano technology, Peroxydisulfate,Acid red 87, nanosilver
Introduction
Pollution from dyeing industries often contains small amounts of organic materials that require
specific management. Removing these compounds from textile wastewater and adopting some
methods with the highest removal efficiency and the lowest cost is a necessity. Advanced oxidation
method is a method for removing such wastewaters.
The present study was carried out to investigate the effect of
silver nanoparticles to catalyzed
peroxydisulfate in order to removal of Acid red 87 from contaminated water, the simultaneous use
of peroxydisulfate and nanosilver significantly increased the removal efficiency. The effects of
various parameters such as Peroxydisulfate concentration, contaminant concentrations and the
dosage of silver nanoparticles on the dye removal were evaluated
Using oxidizer agent or nano silver catalyst alone did not lead to any removal, while the
simultaneous use of Peroxydisulfate and nanosilver significantly increased removal efficiency. The
effect of various parameters such as Peroxydisulfate concentration changes, changes in contaminant
concentrations and changes in concentrations of silver nanoparticles on dye removal were studied.
Ag
1
S2O8(‐2)
Abs
0.8
0.6
0.4
0.2
0
0
5
10
15
20
25
30
35
Time(mi
Fig 1., [S2O82-]0=10mM, pH0=natural, T0=250C, Nano [Ag]=0.125grL-[DYE]0= 20mgL-
1141
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Conclusions
Results showed that increasing the concentration of peroxydisulfate and nano-silver catalyst
can increase the rate of pollutants removal. The optimal amount of nanosilver and the optimum
concentration of peroxydisulfate were estimated 0.125grL-1 and 10 mM, respectively.
References
[1] J. Méndez-Diaz, M. Sanchez-Polo, Advanced oxidation of the surfactant SDBS by means of
hydroxyl and sulphate radicals, Chemical Engineering Journal 163 (2010) 300–306
[2] Khataee A.R, Mirzajani O, UV/peroxydisulfate oxidation of C. I. Basic Blue 3: Modeling of
key factors by artificial neural network,Desalination xxx (2009) xxx–xxx
[3] Daneshvar.N, Khataee. A.R. ,Rasoulifard.M.H, Dorraji.M , Removal of Organic Dyes from
Industrial Wastewaters Using UV/H2O2,UV/H2O2/Fe (II), UV/H2O2/Fe (III) Processes,
[4] Babu J., Sreekantha V., Joshi K., Bhattacharya K., "Silver ion catalyzed oxidation of primary
aliphatic amines by potassium peroxydisulfate- Akinetic study", Bulletin of the chemical society of
1820–1823. ,japan, 49, (1976)
[5] J. Saien ,A.R. Soleymani, J.H. Sun Parametric optimization of individual and hybridized AOPs
of Fe2+/H2O2 and UV/S2O8 for rapid dye destruction in aqueous media, Desalination (2011) Inpress.
of Fe2+/H2O2 and UV/S2O8 for rapid dye destruction in aqueous media, Desalination (2011) Inpress.
1142
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
Removal of organic dye of Direct blue 129 from contaminated water using
advanced oxidation process in the presence of UV irradiation and
immobilized TiO 2 nanopowder on glass beads
M. Shahgholi
a
b
*a
, M. H. Rasoulifard b and J. Khamesi c
Department of Chemistry & Environment,University of Zanjan ( [email protected])
Department of Chemistry & Environment , University of Zanjan , Iran. ([email protected])
c
Department of Environment Protection , Zanjan Province. ([email protected])
Keywords:Advanced Oxidation Process, Direct blue 129, Ammonium peroxydisulfate , NanoTitanium dioxide, UV irradiation, Wastewater Treatment.
Introduction
Synthetic dyes are extensively used in many industries. About 15% of the total world production of
dyes is lost during textile dyeing which is released in textile effluents. Treatment of colored
wastewater from these industries is a serious problem that has attracted the attention of many
researchers.
Among all of the methods for the treatment of wastewater, "Advanced Oxidation Processes" (AOPs)
are one of the newest methods have been developed to degrade biorefractory organics industrial
effluents.
In this study, the use of nanotechnology as a new method for organic Direct blue129 dyes removal
in small amounts from aqueous solutions which is used in the dyeing of cellulosic fibers, cotton and
wool and nylon fibers was studied through the advanced oxidation process in the presence of
immobilized TiO2 nanopowder on glass beads under a set of effective parameters(initial
concentration of S2O8,Direct blue129,Temperature and PH.
Using oxidizer agent or nano TiO2 catalyst alone or UV irradiation lone too, did not lead to any
removal, while the simultaneous use of Peroxydisulfate and nano TiO2 and UV irradiation
significantly increased removal efficiency.
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1
uv
Tio2
0.6
s2o8 5mM
A
b
s
0.8
uv/Tio2
0.4
uv/s2o8
0.2
uv/Tio2/s2o8
0
0
5
10
15
20
25
30
35
Time(min)
Fig 1.UV(LED)=18W, [S2O82−]o = 5 mM , [DYE]o = 20 mg L-1, pHo = natural,T= 25◦C , glass bead Nano-TiO2
Conclusions
Our results suggest that the oxidative treatment of Direct blue 129 by ammonium
peroxydisulfate activated with Nano TiO2 and UV irradiation is a viable, fast, economic and
environment friendly option for removal of the textile dyes from effluents.
References
[1] Khataee A.R, Mirzajani O, UV/peroxydisulfate oxidation of C. I. Basic Blue 3: Modeling of key
factors by artificial neural network,Desalination xxx (2009)
[2] Daneshvar.N, Khataee. A.R. ,Rasoulifard.M.H, Dorraji.M , Removal of Organic Dyes from
Industrial Wastewaters Using UV/H2O2,UV/H2O2/Fe (II), UV/H2O2/Fe (III) Processes,
[3] Daneshvar. N. Salari. D., Niaei. A., Rasoulifard. M.H., Khataee, A.R. "Immobilization of TiO2
Nanopowder on Glass Beads for the Photocatalytic Decolorization of an Azo Dye C.I. Direct Red
23", Journal 0f Environmental Science and Health, Part A, 40, (2005), 1605–1617.
of Fe2+/H2O2 and UV/S2O8 for rapid dye destruction in aqueous media, Desalination (2011)
Inpress.
1144
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
‫ه ﯽ‬
DFT study on organic dye sensitizer DST with various acceptors for DSSCs
Z.Kohpayma*
Department of Chemistry, College of Sciences, Yasouj University, Yasouj, Iran
[email protected]
Keywords: Dye sensitizer, Electronic structure, Density functional theory, DSSCs
Abstract
The geometries and electronic structures of organic dye sensitizers DST with various acceptors
were studied by using density functional theory (DFT).
Introduction
Future energy supply and energy security will demand revolutionary advances in technology in
order to maintain forward today’s general standard of living and economic prosperity [1]. Faced
with high and rising energyprices, limitations in energy supply, and growing concerns about climate
changes and their environmental- and health-related effects, the magnitude of the problems may
seem daunting. On the other hand, the quality of human life depends to a large degree on the
availability of energy. The solar energy, the gift of nature, fulfils most of humanities energy needs
[2]. The photochemistry research involving chemical change, occurred by the absorption or
emission of visible light or UV radiation, emphasizes fundamental processes aimed at the capture
and conversion of solar energy [3].The dye sensitizers in this study are all donor-bridge-acceptor
system.The role of different acceptors in geometries, electronic structures were analyzed in a
comparative study of DSSCs.The computations of DST geometries and electronic structures were
performed using DFT in B3LYP/6-31+G* level and all calculations were performed without any
symmetry constraints. Natural Bond Orbital (NBO) analysis was performed in order to analyze the
charge populations of the dye DST with various acceptors.
Results and discussion: The aniline group in DST is main chromophore that contributed to the
sensitization. The interfacial electron transfer is due to an electron injection processes from excited
dyes to semiconductor conduction band. The calculated
geometries indicate that the strong
conjugated effects are formed in the dyes.For DST, the natural charges of acetic acid, diethylamino,
styryl, thieno[b]thienyl, oxo-thioxothiazolidinyl and methylene groups are 0.28, 0.00, 0.11, 0.08, 0.53 and 0.07e, respectively.The optimized geometries of the dye DST with different acceptors and
β-electron distribution of them are shown below . In this figures, DST's acceptor was replaced with
carboxylphenyl, cyanoacrylic acid, DCBP, TCF and NO2 respectively.
1145
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Conclusion: As it is obvious from the figures,NO2 has the best electron distribution, the easier
efficient electron transfer through the dye and more electron distribution in the acceptor, the
better solar cell performance theoretically that is in good agreement with NBO's results.
β-electron distribution
Optimized structure of dyes
References
[1] R.E. Smalley, Future global energy prosperity: the terawattchallenge, MRS Bull. 30 (2005)
412–417.
[2] Frances S Sterrett (ed) Alternative Fuels and the environment (1994); D. Gust, T. A. Moore, A.
L. Moore Molecular approaches to Artificial Photosynthesis.
[3] E A Rohlfing, W J Stevens and M E Gress Project of Chemical Sciences, Geosciences and
Biosciences (2003).
1146
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Conference
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Preparation of polyaniline/ metal oxide/ MWCNT nanostructured fibers
using wet spinning as electrode materials for aqueous redox supercapacitors
A. Mirmohseni * a , M. S. Seyed Dorraji b and M. G. Hosseini a
a
Faculty of Chemistry, University of Tabriz, Tabriz, Iran
([email protected])
b
Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan, Iran
Keywords: Polyaniline, Electrochemical capacitor, Fiber, Nanocomposite, Metal oxide.
Introduction:
Conducting polymer fibers are new and interesting alternative to films or membranes. Fibers can be
used as microelectrodes for developing a wearable power source for wearable diagnostic systems
[1]. Recently, carbon nanotubes have been incorporated in conducting polymers to form composite
electrode materials for supercapacitor. The presence of carbon nanotubes prevent the polymers from
mechanical changes (shrinkage and breaking) and also improve charge transfer.More recently, an
interest in metal oxides has gradually emerged because the addition of oxides can improve the
cycling stability of energy-storage devices [2]. The aim of this study is to develop a novel
polyaniline-based fiber capacitor. Therefore, stand-alone polyaniline-metal oxide nanocomposite
fibers were prepared by a wet spinning method and employed as an electrode. Multi-wall carbon
nanotubes have also been added into the spinning solution to improve the electrical and mechanical
properties of polyanilinenanocomposite fibers.
SnO2and Fe3O4 nanoparticles were prepared based on precipitation and co-precipitation methods,
respectively [3, 4]. The PAni-SnO2, PAni-Fe3O4 and PAni-TiO2nanocomposites were synthesized
by chemical oxidative in-situ polymerization of aniline. Novel fiber capacitor electrodes presented
in
this
work
are
produced
via
a
wet
spinning
technique.The
capacitance
of
polyanilinenanocomposite fibers was determined by three main methods, namely, electrochemical
impedance spectroscopy, constant-current charge-discharge and cyclic voltammetry.
TEM images (Fig. 1) of thin film obtained by ultra-microtome show the presence of nanoparticles
(black parts) throughout the PAni matrix.Cyclic voltammetry measurements were performed to
investigate the influence of nanoparticles on the electrochemical properties of PAnifibers (Fig.
2).The specific capacitance of PAni, PAni-MWCNT, PAni-MWCNT-TiO2, PAni-MWCNT-Fe3O4
and PAni-MWCNT-SnO2 fibers was calculated to be 9.8, 12.1, 14.2, 24.1 and 29.7 F cm-2 at the
scan rate of 10 mV s-1, respectively.The specific capacitance of PAni, PAni-MWCNT, PAni1147
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MWCNT-TiO2, PAni-MWCNT-Fe3O4 and PAni-MWCNT-SnO2 fibers was calculated using
charge-discharge curvesto be 9.5, 12.3, 13.8, 23.7 and 28.9 F cm-2, respectively.There is semicircle
impedance arc in the high frequency region on all Nyquist diagrams. The impedance arc obtained at
different acidic solutions is approximately one-fifth of a circle. In addition, the impedance in the
imaginary part increases more sharply with decreasing frequency, which is indicative of a faradaic
process produced by the bulk redox transitions of polymers and metal oxides.
(a)
(b)
(c)
(d)
Current density (mA cm-2)
Fig 1. TEM images of (a) PAni, (b) PAni-TiO2-MWCNT, (c) PAni-Fe3O4-MWCNT and (d) PAni-SnO2-MWCNTCS.
350
250
150
50
‐50
‐150
‐250
e
‐0.3
d
c
b
a
0.2
0.7
Potential ( V vs. SCE)
Fig 2.Cyclic voltammograms of (a) PAni , (b)PAni-MWCNT, (c)PAni-MWCNT-TiO2, (d) PAni-MWCNT-Fe3O4 and
(e) PAni-MWCNT-SnO2 fibers in 1 M HCl or 1 M HCl and 0.5 M Na2SO3 at a scan rate of 10 mV s-1.
Conclusions
The sequence of fibers as electrode with respect to the increasing of specific capacitance is PAniMWCNT-SnO2> PAni-MWCNT-Fe3O4>PAni-MWCNT-TiO2>PAni-MWCNT>PAni.
References
[1]. Pauliukaite, R.; Brett, C. M. A.;Monkman, A. P.; Electrochim. Acta 2004, 50, 159.
[2]. Hsieh, C.-T.; Chang, C.-C., Chen,W. Y.; Hung,W.-M.; J. Phys. Chem. Solids2009, 70, 916.
[3]. SeyedDorraji, M. S.; Aber, S.; Hosseini, M. G.; Int. J. Nanotechnol.2009, 6, 984.
[4]. Meng, J. H.; Yang, G. Q.; Yan, L. M.; Wang, X. Y.; Dyes Pigm.2005, 66, 109.
1148
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Conference
‫ه ﯽ‬
Synthesis and antibacterial activityof silver
nanoparticlesusingresistance bacteria to heavy metals
Fatemeh Khosravi a* , Mojtaba Mohseni a ,Maryam Mohajerani a , Mohammad Javad
Chaichi b
a
Department Molecular and Cell Biology, University of Mazandaran, Babolsar, Iran
(*[email protected])
b
Department ofAnalytical chemistry, University of Mazandaran, Babolsar, Iran
Keywords: Silver nanoparticles, heavy metal, bacterium, antibacterial activity.
Introduction
Different chemical and physical methods have been applied for synthesizingof nanoparticles [1].
These methods have different problems like using poisonous solutions, production of hazards
byproducts and high energy consumption [2, 3]. The usage of microorganisms in synthesizing of
nanoparticles which is biosynthesis has been enormously noticed by scientists [4, 5]. Silver
nanoparticles have important applications in the field of biology such as antibacterial agent [6].
Different microorganisms have this ability to synthesize nanoparticles but the usages of bacteria
with ability to remediate heavy metals are interested. In this research synthesis of silver
nanoparticles (Ag-NPs) has been explored using heavy metal resistant bacteria. Also, Antibacterial
property of silver nanoparticles against Escherica coli and Pseudomonas aeruginosa was
investigated.
A bacterium resistance to heavy metal was isolated using culture medium contains different lead
concentration. In order to determine the level of resistance to lead, the minimum inhibitory
concentration was performed. A bacterial isolate with most resistance to heavy metals was screened
for synthesis of silver nanoparticles. Synthesizing of silver nanoparticles was performed by
reducing of Ag+ agues ions using the culture supernatant of heavy metal resistant bacteria. Synthesis
of nanoparticles was determined using spectrophotometry, XRD and TEM. To considerif silver
nanoparticles have antibacterial effects, the antibacterial activity of the nanoparticles was
investigated using disk diffusion Kirby- Bauer method. It was undertaken against test bacterial
strains on Muller-Hinton agar plates.
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The isolate M.Kh1 was shown high resistance to lead, therefore, this isolate selected for further
studies. The silver nanoparticles were characterized by UV–visible spectroscopy. A strong, broad
peak located between 420 and 430 nm was observed for the silver nanoparticles. Observation of this
peak, assigned to a surface plasmon, is well-documented forvarious metal nanoparticles with sizes
ranging from 2 to 100 nm. The analysis of this precipitate fraction by XRD confirmed the presence
of elemental silver signal. In addition, these results indicated that Ag-NPs synthesized by
supernatants of M.Kh1 showed antibacterial activity.
References
[1] Ghorbani, H. R., Attar, H., Safekordi, A. A., &Sorkhabadi, S. M. R.(2011). Optimization of
Silver Nanoparticles Production by E. coli Bacterium (DH5a) and the Study of Reaction Kinetics.
Asian Journal of Chemistry; Vol. 23, No. 11, 5111-5118.
[2] W. Zhang, Z. Chen, H. Liu, L. Zhang, P. Gao, D. Li. (2011). Biosynthesis and structural
characteristics of selenium nanoparticles by Pseudomonas alcaliphila. Colloids and Surfaces B:
Biointerfaces 88 (2011) 196– 201
[3] R.Y. Parikh, S. Singh, B.L.V. Prasad, M.S. Patole, M. Sastry, Y.S. Shouche, Chem-BioChem 9
(2008) 1415–1422.
[4] A. Bharde, D. Rautaray, V. Bansal, A. Ahmad, I. Sarkar, S.M. Yusuf, M. Sanyal, M.Sastry,
Small 2 (2006) 135–141.
[5] Narayanan, K. B., & Sakthivel, N. (2010). Biological synthesis of metal nanoparticles by
microbes. Advances in Colloid and Interface Science, 156(1), 1-13.
[6] Shahverdi, A. R., Fakhimi, A., Shahverdi, H. R., & Minaian, S. (2007). Synthesis and effect of
silver nanoparticles on the antibacterial activity of different antibiotics against Staphylococcus
aureus and Escherichia coli. Nanomedicine: Nanotechnology, Biology and Medicine, 3, 168-171.
1150
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Semiconductor nanoparticles synthesis usingbacteria isolated
fromheavy metal contaminated areas
Fatemeh Khosravia*, Mojtaba Mohsenia, Maryam Mohajerania, Mohammd Javad
Chaichib
aDepartment Molecular and Cell Biology, University of Mazandaran, Babolsar, Iran
b Department ofAnalytical chemistry, University of Mazandaran, Babolsar, Iran
[email protected]
Key Words: Selenium nanoparticles, bacteria, heavy metal.
Introduction
Nanoparticles ranging from 0.1 nm to 1000 nm in size have demonstrated new physical and
chemical properties. Semiconductor nanoparticles have excellent nonlinear properties, saturable
absorption and optical bistability (1, 2). Nanoparticles are been synthetized by different chemical
and physical methods (3). These methods have different problems like usage of poisonous
solutions, production of hazards byproducts and high energy consuming (4, 5). Application of
microorganisms to synthetize nanoparticles has been noticed enormously by scientists and
researchers prefer it’s the biosynthesis (6). Various microorganisms have this ability to synthesize
nanoparticles but the usages of bacteria that remediate heavy metals are so noticeable. In this study,
a bacterium that isolated from a contaminated wastewater was used for synthesis of selenium
nanoparticles (Se-NPs). UV–Vis spectroscopy and X-ray diffraction (XRD) studies were carried out
to confirm Se-NPs formation.
Heavy metal resistance bacteria were isolated using culture medium contains different lead
concentration. In order to determine the level of resistance to lead, the minimum inhibitory
concentration method was used. Then the heaviest metal resistance bacterium was used for
synthesizing of selenium nanoparticles. About 1ml active culture of isolate M.Kh2 was added into
100 ml Muller-Hinton medium containing 4 mM sodium selenite. The flask was incubated on
orbital shaker at 33°C, 150 rpm for 48 hours. Then selenium nanoparticles were examined for their
optical absorption property by using a UV-Vis spectrophotometer. In addition, the formation of
selenium nanoparticles was checked using X-ray diffraction (XRD).
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To examine the resistance activity of bacterium to heavy metal, MIC was undertaken using different
metal concentration. The isolate M.Kh2 was shown high resistance to lead, and therefore, this
isolate selected for further studies. After exposing activated M.Kh2 to sodium selenite and
incubating for 48 hours, the color of solution changed from clear light-yellow to red. The red color
of solution indicates the presence of Se nanoparticles. According to the UV–visible spectrum of the
prepared Se NPs, absorption peak appeared at 250 nm, indicating the formation of Se NPs. The
Results of analysis by XRD confirmed the presence of Se NPs.
References
[1] M.C. Daniel, D. Astruc, Gold nanoparticles: assembly, supramolecularchemistry,quantum-size-related
properties, and applications toward biology, catalysis, and nanotechnology, Chemical Reviews 104 (2003)
293–346.
[2] G. Schmid, Large clusters and colloids. Metals in the embryonic state, Chemical Reviews 92 (1992)
1709–1727.
[3] Ghorbani, H. R., Attar, H., Safekordi, A. A., &Sorkhabadi, S. M. R.(2011). Optimization of Silver
Nanoparticles Production by E. coli Bacterium (DH5a) and the Study of Reaction Kinetics.Asian Journal of
Chemistry; Vol. 23, No. 11, 5111-5118.
[4] W. Zhang, Z. Chen, H. Liu, L. Zhang, P. Gao, D. Li. (2011). Biosynthesis and structural characteristics
of selenium nanoparticles by Pseudomonas alcaliphila.Colloids and Surfaces B: Biointerfaces 88 (2011)
196– 201
[5] R.Y. Parikh, S. Singh, B.L.V. Prasad, M.S. Patole, M. Sastry, Y.S. Shouche, Chem-BioChem 9 (2008)
1415–1422.
[6] A. Bharde, D. Rautaray, V. Bansal, A. Ahmad, I. Sarkar, S.M. Yusuf, M. Sanyal, M.Sastry, Small 2
(2006) 135–141.
1152
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Conference
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Study on Nanostructural properties of polystyrene organic
nanomaterial in devices
Bahari Ali1; Ashrafi Feridoun2; Moradinejad zahra3*;
1
Faculty of Physics, University of Mazandaran, Babolsar, Iran
2
Faculty of Science, Payame Noor University of Sari, Sari, Iran
3
Education office, Sari2 District,Iran ([email protected])
Keywords:Nano Structures,Organic Material,polystyrene,Nano composite, sol-gel method.
Introduction
Recently,There has been an increasing interest in organic-based electronics for low cost and large
area processability .[1]
Nowadays, the devices and electronic chip̕s scales have been entered into the nano scale area .
Organic thin film transistors with organic /inorganic hybrid gate dielectric showed good
electrical properties such as higher dielectric constant and lower leakage current at<40 nm
Organic materials can not be used as a good gate dielectric due to their lower constant and
higher leakage current.[2-3]
Methods
we added polystyrene with different concentration to lanthanium oxide nano particle solution and
synthesized it with sol-gel method . we calcinate it in 300° C.Their nano structural properties were
studied by using XRD, SEM and X –powder.
Results
The XRD and SEM findings showed Nano Structures of polysteren /La2O3 was amorphous. Nano
composite was more amorphous due to increase in polysteren concentration.(figure 1)
Conclusions
The obtained results indicated that the La2O3/Polystyrene had an amorphous structure which can
reduce leakage current and tunneling current due to its high EOT thickness. They can be used
for the future OTFT flexiable devices.
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60
0.28g
50
Intensity(A.u)
40
0.14 g
30
20
0.07g
10
0
10
20
30
40
50
60
70
2Theta
Fig1.Typical X-ray diffraction patterns of the synthesized products calcined different concentration.
References
1- Puigdollers,J.Voz c, Orpella ,A, Quidant ,R, Martin I, Vetter M, Alcubilla R (2004) pentacene
thin –film transistors with polymeric gate dielectric. Org Elctron 5:67-71
2- Facchetti, A,Yoon, M.H, Marks, T.J.( 2005 ).Adv.Mater. 17o1705
3- Veres, J.S, Gier, O, Lioyd ,G,Leeuw,D.D,(2004),Chem. Mater. 16,963.
1154
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Conference
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Synthesis of multiwalled carbon nanotubes over Ni catalyst supported
by different phases of TiO 2 substrate via Catalytic Chemical Vapor
Deposition (CCVD) method
F. Doustan a , A. A. Hosseini * a , M. Akbarzadeh Pasha a andL. Ebrahimi a
a
Department of Solid State Physics, Faculty of sciences, University of Mazandaran, Babolsar, Iran
([email protected])
Keywords: Carbon nanotubes, CCVD, Wet impregnation, Tio2 substrate, Ni catalyst.
Introduction
It is well known that the most effective catalysts for the CVD growth of CNTs are transition metal
elements from periodic table of elements, such as Fe, Co, Ni and Mo.[1] Zein et al. have shown that
TiO2 supported NiO catalyst records the lowest activation energy in methane decomposition into
CNTs and hydrogen.[2] Saraswat et al. have investigated effect of the metal loading, catalyst
preparation method and reaction temperature on methan conversion and on the properties of the
obtained carbon.[3] In this work, we study the properties of CNTs synthesized over Ni
nanoparticles supported on both rutile and anatase phases of TiO2 substrate.
Experimental
Ni(NO3)2.6H2O (Aldrich) salt was used as the source of Ni nanoparticles. Metal nitrate was
dissolved in distilled water and separately impregnated onto distilled water solution of rutile and
anatase phases of TiO2 powder (Merck) with concentration ratio of 20/80 wt% for catalyst/substrate
e.g. Ni/Tio2. The mixture was executed under ultrasonic reflux, followed by drying on a hot plate
and calcinated in an oven at 500ºC for 2 hours. 50 mg of the produced catalyst was used for CNTs
synthesis by a Thermal CVD (TCVD) process at atmospheric pressure under argon atmosphere.
The precursor gas composed of acetylene and argon (C2H2/Ar = 15/150 sccm) flows over the
catalyst at 700C for 15 minute.
Fig.1 shows the XRD patterns of the two catalysts samples. According to this figure the
approximate size of Ni nanoparticles (by replacement of peak characteristics at 2θ=43.3 according
to Debye-Scherrer equation) formed on Ni/TiO2-anatase and rutile were estimated 17 nm and 29.6
nm, respectively.[4] It means that smaller Ni nanoparticles are obtained on anatase phase of Tio2
substrate. Besides, the carbon yield percentage and average growth rate of the catalyst samples,
which are presented in Table 1 shows that, Ni nanoparticles have more catalytic activity on anatase
phasecompared to rutile phase of Tio2 substrate. Fig.2 shows the SEM images and diameter
distribution diagrams of synthesized CNTs.
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It is clear that grown CNTs on anatase substrate have denser morphology compared to rutile one.
Furthermore, the average diameters of grown CNTs on Ni/Tio2 anatase and rutile catalysts were
obtained 25 nm and 48 nm, respectively. These results are in agreement with previous results of
XRD analysis, that indicates the size of Ni nanoparticles formed on Ni/TiO2-anatase is smaller than
of Ni/TiO2-rutile. For the sake of briefness, here the results of Raman analysis was omitted.
40
20
35
18
16
CNTs Percent (%)
CNTs percent (%)
30
25
20
15
10
14
12
10
6
4
5
0
8
2
0
15-20 20-25 25-30 30-35 35-40 40-45 45-50
15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 65-70 70-75
CNTs Diameter (nm)
CNTs Diameter (nm)
Fig 2. SEM images of CNTs produced over (a) Ni/TiO2-anatase; and (b) Ni/TiO2-rutile catalyst.
Conclusions
It was observed that the phase of Tio2 substrate affects intensely the characteristics of grown CNTs.
The grown CNTs on Ni/TiO2-anatase catalyst have smaller average diameter and higher density
compared to Ni/TiO2-rutile.
References
[1]. Dupuis, A. C. Progress in Materials Science, 2005, 50, 929-961.
[2]. Zein, S. H. S.; Mohamed, A. R.; Sai, P. S. T. Ind. Eng. Chem. Res, 2004, 43, 4864-4870.
[3]. Saraswat, S. K.; Pant, K. K. Energy and Enviromental Engineering Journal, 2012, 1, 81-85.
[4]. Yue, W.; Zhou, W, J. Mater. Chem, 2007, 17, 4947-4952.
Catalysts
yield
Ni/TiO2-
700C
n
anatase
Ni/TiO2-rutile
80%

(  ) T iO 2 -ru tile
growth
(  ) T iO 2 -a n a ta se
rate(mg/
min)
 

(a )
Intensity (a.u.)
re
Average

2.67
1.33
10
(  ) N iO








   
20
30
Tabel (1):The carbon yield percentage and average growth rate of produced CNTs.
Fig 1. XRD patterns of (a) Ni/TiO2-anatase;and (b) Ni/TiO2-rutile catalysts.
1156


(b )
40%


Temperatu
Carbo
40
50
2  (d egree)
    

60
70
80
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Conference
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Growth of carbon nanotubes over Fe-Co and Ni-Co bimetallic catalyst
supported on Al 2 O 3 by Catalytic Chemical Vapor Deposition (CCVD)
method
L. Ebrahimia, A. A. Hosseinia, M. Akbarzadeh Pashaa and F. Doustana
a
Department of Solid State Physics, Faculty of sciences, University of Mazandaran, Babolsar, Iran
([email protected])
Keywords: CNT, CCVD, Wet impregnation, bimetallic catalyst, Alumina substrate.
Introduction
Since carbon nanotubes (CNTs) were discovered by Iijima in 1991 [1], they have attracted
extensive attentions because of their unique structural, electronic, thermal and mechanical
properties. There are three major methods for synthesizing CNTs: arc discharge, laser ablation and
chemical vapor deposition (CVD).[2]In this paper, we will further examine the effect of alumina
supported bimetallic catalysts Fe-Co and Ni-Co on the characteristics of produced CNTs such as
carbon yield and average diameter.
Experimental
Fe-Co and Ni-Co bimetallic catalysts on Al2O3substrate were prepared by impregnation method.
The metal salts dissolved in distilled water, then impregnated with the water solution of Al2O3
powder. The mixture was dried to evaporate the solvent.Subsequently, the product was calcinated
for 2 h at 5000C.50 mg of the produced catalyst was used for synthesizing CNTs by a Thermal CVD
(TCVD) process at atmospheric pressure. The precursor gas composed of acetylene and argon
(C2H2/Ar=15/150sccm) flows over the catalyst at 700C for 15 minute.
Fig1.shows the XRD patterns of prepared catalytic substrate samples. According to this figure the
approximate size of Fe and Co nanoparticles (by replacement of corresponding peak characteristics
in Debye-Scherer equation) formed on Fe-Co/Al2o3catalyst is 24 nm and 9 nm, respectively.
Similarly approximate size of Ni and Co nanoparticles formed on Ni-Co/Al2o3catalyst is 41 nm and
17 nm, respectively. The results showsthatcatalyst particles in case of Fe-Co/Al2O3are better
dispersed so formed smaller crystallites compared to Ni-Co/Al2o3 substrate.[3] As shown in Table 1
carbon yield for Fe-Co/Al2O3 is relatively higher compared to Ni-Co/Al2O3catalyst. It means that
Fe-Co bimetallic nanoparticles on Al2O3substrate show better catalytic activity compared to Ni-Co
nanoparticles. Furthermore it can be concluded that decrease of catalytic nanoparticle size caused to
increase in carbon yield.
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
700 0C
Catalysts
Carbon yield
Fe-Co/Al2O3
160%
Ni-Co/Al2O3
20%
Intensity (a. u.)
(b)
Temperature
( ) A l2 O 3

(  ) N iO
(  ) Fe 2 O 3

( ) C o 3 O 4


 
(a)
10
20
30
40
50
60
70
80
2  (degree)
Table (1): Carbon yield of Fe-Co/Al2O3 and Ni-Co/Al2O3 catalysts.
Fig1.XRD pattern of prepared catalysts (a) Fe-Co/Al2O3 and(b) Ni-Co/Al2O3.
Fig 2. Shows the SEM images of grown CNTs. The average diameters of produced CNTs on FeCo/Al2O3 and Ni-Co/Al2O3 catalysts were obtained 21 nm and 24 nm,respectively.Thus, the grown
CNTs on Fe-Co/Al2O3 catalyitic substrate have smaller diameters compared to grown CNTs on NiCo/Al2O3 one.
35
35
30
30
25
CNTs %
CNTs %
25
20
15
20
15
10
10
5
5
0
10-15
15-2o
20-25
25-30
30-35
CNTs Diameter (nm)
0
15-20
20-25
25-30
30-35
35-40
CNTs Diameter (nm)
Fig2. SEM images of CNTs grown at 7000C on (a) Fe-Co/Al2O3(b)Ni-Co/Al2O3catalysts.
Conclusions:
CCVD was utilized to produce multiwall carbon nanotubes from acetylene as feed gas at 7000C
onFe-Co/Al2O3 and Ni-Co/Al2O3catalytic substrate prepared by wet impregnation method. It was
found that bimetallic catalyst nanoparticles dispersed on Fe-Co/Al2O3 substrate possess smaller
crystallite sizes and exhibits more catalytic activity in comparison whit Ni-Co/Al2O3.
References:
[1]. Iijima. S. Nature, 1991, 354, 56.
[2]. T. T. Cao.; T. T. T. Ngo.; V. C. Nguyen.; X. T. Than.; B. T. Nguyen.; N. M. Phan. Adv. Nat.
Sci. Nano science & Nanotechnology, 2011, 2, 035007.
[3]. X. Zhang.; J. Liu, Y. Jing.; Y. Xie. Appl. Catal, A, 2003, 240, 143.
1158
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Conference
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Preparation and characterization of copper oxide nanoparticles
fromcopper(I) thiosemicarbazone complexes
Ensieh Shahsavani a, * , Nourollah Feizi a , Aliakbar Dehno Khalaji b
a
Department of Chemistry, Payame Noor University, PO Box 19395-3697 Tehran, IRAN
b
Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran
*
E-mail address: [email protected]
Keywords: Copper(I) thiosemicarbazone; CuO nanoparticles; XRD; SEM.
Copper oxide, a p-type semiconductor with a band gap of 1.2 eV, has been particularly interesting
because of their properties and applications such as optical properties [1-4]. Widespread
applications of CuO nanoparticles insisted several methods of preparation and characterization of
CuO nanoparticles [5-9]. Herein, we report the synthesis and characterization of copper oxide
nanoparticles using thermal decomposition of [CuI(CaTSC)]2 (1) and [Cu(Meca-TSC)I]2 (2).
To a solution of copper(I) iodide (0.2 mmol) in CH3CN (15 mL) is added a solution of CaTSC or
Meca-TSC (0.2 mmol in 15 mL CH3CN) and stirred for 45-60 min to form a yellow precipitate.
Then, the complexes are loaded on a crucible and placed in oven to heat at a rate of 10ºC/min in
air. Nanoparticles of CuO are produced at 600ºC after 3 h. The synthesized CuO nanoparticles
are characterized by XRD and SEM.
The structure and the phase composition of CuO nanoparticles, obtained after calcinationat 600 ºC
for 3 h, have been ascertained by powder XRD analysis (Fig. 1). All diffraction peaks can be well
indexed to the monoclinic structure of copper oxide (JCPDS database No. 05-0661) [10]. Absence
of any impurity peaks from other phases indicates its high purity. XRD results are in close
agreement with the FTIR spectra. Broadening of the diffracted lines indicates the higher
crystallinity of CuO nanoparticles [11].
The detailed morphology and structures of CuO nanoparticles are further characterized by SEM
images (Fig. 2) which clearly indicate similar morphologies and size of CuO nanoparticles. They
also indicate that CuO nanoparticles remain agglomerated having almost uniform in size.
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١٣٩٢ ‫ آﺑﺎن ﻣﺎه‬٩ ٧
Conference
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Fig. 1.
Powder XRD pattern of CuO nanoparticles prepared from 1 (left) and 2 (right)
Fig. 2. SEM images of CuO nanoparticles prepared from 1 (left) and 2 (right)
References
[1] D.I. Son, C.H. You, T.W. Kim, Appl. Surface Sci. 255 (2009) 8794-8797.
[2] X. Jia, H. Fan, W. Yang, J. Disp. Sci. Tech. 31 (2010) 866-869.
[3] D. Das, B.C. Nath, P. Phukon, S.K. Dolui, Coll. Sur. B101 (2013) 430-433.
[4] C.-Y. Chiang, K. Aroh, S.H. Ehrman, Int. J. Hydrogen Energy 37 (2012) 4871-4879.
[5] K.G. Chandrappa, T.V. Venkatesha, J. Exp. Nanosci. 8 (2013) 516-532.
[6] X. Jiang, T. Herricks, Y. Xia, Nano Lett. 2 (2002) 1333-1338.
[7] H. Xu, J. Huang, Y. Chen, Integ. Ferroelectrics 129 (2011) 25-29.
[8] M. zhang, X. Xu, M. Zhang, J. Disp. Sci. Tech. 29 (2008) 508-513.
[9] R. Wu, Z. Ma, Z. Gu, Y. Yang, J. All. Compd. 504 (2010) 45-49.
[10] S. Reddy, B.E. Kumara Swamy, H. Jayadevappa, Electrochim. Acta 61 (2012) 78-86.
[11] H. Chen, F. Feng, Z.-L.Hu, F.-S.Liu, W.-Q.Gong, K.-X. Xiang, Trans. Nonferrous Met. Soc.
China 22 (2012) 2523-2528.
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Nanochemistry and Thechnology

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