Inferred Pa(V) Complex Formation via Selective Extraction

Inferred Pa(V) Complex Formation via Selective Extraction

1

Inferred Pa(V) Complex Formation via Selective Extraction by Aliphatic Alcohols and Mesoporous Carbon Materials Andrew Knight
University of Iowa SACSESS 22 April 2015
Warsaw, Poland
Radiochemistry at The University of Iowa
2
3
Pa in Conventional Fuel Cycles
Pa 233
Pa 231
Figures by Andrew Nelson
http://energyfromthorium.com/2011/01/30/china‐initiates‐tmsr/
4
Thorium Fuel Cycle

Breeds natural 232Th to make fissile 233U through 233Pa intermediate

India:

Advanced Heavy water Reactor

Molten Salt Breeder Reactor

Aqueous Suspension Reactor
‐
‐
World Thorium Deposits Kumari, N., Desalin. Water Treat., 2012, 38,46‐51
IAEA and OECD, Uranium 2014: Resources, Production, and Demand
5
Extraction Studies
1. Aliphatic Alcohols
1‐octanol
2‐ethyl‐hexanol
2. Modeling
3.Mesoporous Carbon
2,6‐dimethyl‐4‐heptanol
(diisobutylcarbinol; DIBC)
6
1. Pa Extraction By Alcohols
% Activity Extracted 100
% Pa Extracted in HCl
% Pa Extracted in HNO3
% Extracted≈
75
[Pa]A + [Pa]O
5 mL organic
40% extractant
60% dodecane
50
25
DIBC
2-Ethyl-hexanol
1-octanol
DIBC
2-Ethyl-hexanol
1-octanol
0
[Pa]O
2
4
6
[HCl]
8
2
4
6
[HNO3]
8
5 mL Aqueous Acid (HCl , HNO3) Ranging from 1‐9 M
7
Pa and Other Metals Extraction
100
Pa
Pa
% Activity Extracted % Extracted by DIBC in HNO3
% Extracted by DIBC in HCl
Ga
75
50
25
0
2,6‐dimethyl‐4‐heptanol
(diisobutylcarbinol; DIBC)
Po
Np, Am, Pu, U, Th, Eu, Ba, Ac, Zn 2
4
[HCl]
6
8
Np, Am, Pu, U, Th, Eu, Ba, Ac, Zn, Po, Ga
2
4
6
[HNO3]
8
8
% Pa Extracted in HCl
100%
% Pa Extracted In HNO3
100%
H+ Pa(OH)2(NO3)4‐ (org)
%Extracted
Pa(OH)3Cl+
(aq)
H+ PaCl6‐
(org)
H+ PaOCl4‐
(org)
50%
50%
Pa(OH)2(NO3)3 (aq)
Pa(OH)32+
(aq)
Pa(OH)2(NO3)2+ (aq)
Pa(OH)2(NO3)2+ (aq)
0%
1
3
H+ PaO2Cl2‐ (org)
5
[HCl]
Guillaumont, R. J. Chim. Phys. 1960, 57,1019.
7
9
0%
0
Pa(OH)23+
2
(aq)
4
[HNO3]
6
Spitsyn, V., Doklady AN SSSR. 1964, 157,135.
8
9
Literature proposed Species… [HCl]
Pa Ions
Reference
HNO3
Pa Ions
Reference
1
Pa(OH)4+, PaO(OH)2+
Hageman (1947),
Schreff (1966)
pH >7
Colloids
Starik (1959), Sheidina (1961)
1‐2
Pa(OH)32+, PaO(OH)2+
Guillamont (1966),
Schreff (1966)
pH 5‐7
hydroxide
Starik (1959),
Sheidina (1961)
[Cl‐]= 1 M,
[H+]= 1‐3 M
Pa(OH)3Cl+
Guillamont (1966),
Schreff (1966)
pH 0‐2
Pa(OH)4.50.5+
Starik (1959), Sheidina (1961)
>2 Pa(OH)2(NO3), Pa(OH)2(NO3)4‐
Spitsyn (1964)
2‐4 Pa(OH)3Cl+, PaO(OH)Cl+,
Pa(OH)4Cl2‐, PaO2Cl2‐
Casey (1959), Schreff (1966)
< 3
Hardy (1958)
Pa(OH)Cl3+, Pa(OH)2Cl3, Pa(OH)Cl4‐
Casey (1959) Pa(OH)32+, Pa(OH)3NO3+,
Pa(OH)2(NO3)22+
1‐4
Neutral or Cations with 3+ charge
Starik (1961)
4‐6
Pa(OH)23+, PaO3+, Pa(OH)2Cl4,
PaOCl4‐
Schreff (1966)
1‐5
PaO2(NO3)43‐
Goble (1956)
6
Pa(OH)2Cl4‐, Pa(OH)Cl5‐, PaCl6‐
Casey (1959) 3‐6
Anions with ‐1 and ‐2 charge
Guillot (1966)
6‐8
Pa(OH)Cl62‐, PaCl6‐, PaCl72‐
Schreff (1966)
4‐6
Uncharged Species 6‐9
PaOCl52‐
Goble (1958)
Davydov (1966), Starik (1961)
Pa(NO3)6‐, Pa(NO3)72‐
Starik (1963)
8
PaCl72‐, PaCl83‐
Bagnall (1964),
Schreff (1966)
[H+] = 6 , [NO3‐]= 3‐6 [H+] = 6,
[NO3‐]= 1‐
3
Pa(NO3)5
Starik (1963)
8‐12 Anions with charge 3‐
Starik (1961)
3‐6
10
PaOCl63‐
Guillamont (1966) No consensus on the dominant species Extractant Stoichiometry 10
Log D = m Log [ROHorg] + Log Kex + n Log [Cl‐aq] – j Log[H+] y = m * x
1
+ b
0.6
Pa:Alcohol Stoichiometry in HCl
m= 1.786 ± 0.14
Pa:Alcohol Stoichiometry in HNO3
m= 1.972± 0.02
(DIBC)2PaOx(OH)yClzq‐
0.4
0.8
(DIBC)2PaOx(OH)y(NO3)zq‐
0.6
Log D
Log D
0.2
0
0.4
‐0.2
[HCl] = 6 M
[HNO3] = 6 M
0.2
‐0.5
‐0.25
Log [ROH]
0
‐0.4
‐0.6
‐0.5
‐0.4
‐0.3
Log [ROH]
‐0.2
‐0.1
Anion Stoichiometry
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Log D = n Log [A‐aq] + Log Kex + m Log [ROHorg] – j Log[H+] y = n * x
1
+ b
1.75
Pa:Cl‐ Stoichiometry
4M
H+;
Pa:NO3‐ Stoichiometry
4 M H+; n = 1.94 ± 0.07
n = 5.61 ± 0.58
(DIBC)2PaOx(OH)y(NO3)2q‐
(DIBC)2PaOx(OH)yCl5‐6q‐
‐1
1 M H+; n = 2.08 ± 0.08
(DIBC)2PaOx(OH)y(NO3)2q‐
Log D
Log D
0
1 M H+;n = 4.60 ± 0.38
0
(DIBC)2PaOx(OH)yCl4‐5q‐
0.1 M H+; n = 2.20 ± 0.24
(DIBC)2PaOx(OH)y(NO3)2q‐
0.1 M H+; n = 2.47± 0.9
(DIBC)2PaOx(OH)yCl2‐3q‐
‐2
0.4
[DIBC] = 2.5 M
[DIBC] = 2.5 M
0.5
0.6
Log [Cl‐]
0.7
0.8
‐1.25
0
0.2
0.4
0.6
Log [NO3‐]
0.8
1.0
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2. Log D Main Effects HCl
Parameters: [H+]: 4 - 5 M; [Cl-]: 5 - 5.5 M; [DIBC]: 0.5 - 1 M
50
t‐ Value of Effect
40
B: [H+]
A: [DIBC]
30
C: [Cl‐]
20
10
0
BC
AC
AB
ABC
t‐Value Limit
13
5 M Cl-
5.25 M Cl-
Predicted D 5.5 M Cl-
R2 = 0.99
Actual D
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Log D Main Effect HNO3
Parameters: [H+]: 1 - 3 M; [NO3-]: 3 - 4 M; [DIBC]: 0.5 - 1 M
40
A: [DIBC]
t‐ Value of Effect
30
20
B: [H+]
C: [NO3‐]
10
BC
0
AC
AB
ABC t‐Value Limit
15
3 M NO3-
3.5 M NO3-
4 M NO3Predicted D Predicted Vs. Actual
R2 = 0.99
Actual D
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Further Exploration
 Need to understand the effects of:
 [extractant]
 [anion]
 pH
 Contact time
 Diluent  [analyte metal]
 Radiolysis
 Hydrolysis  Etc…
3. Radiation Shielding Mesoporous Carbon (CMK‐3) Hybrids
CMK‐3 Shows promising properties to shield embedded extraction reagents
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1‐decanol
HDEHP
% 241Am Extracted
100
75
50
HDEHP in dodecane
HDEHP in carbon
25
0
0
250
500
kGy
750
1000
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Weight Distributions
105
Impossible d’afficher l’image.
Weight Distributions on CMK‐3 Weight Distributions CMK:decanol Hybrid  60% (w:w) 1‐decanol
Pa
104
 100 fold increase in Pa extraction
Dw
103
Pa
102
Np
Np
U
Th
101
Am
Th
Aadded‐Asolution Volume (mL)
Dw = x
Asolution
Mass (g)
U
Am
100
1
[HNO3]
10
10 1
[HNO3]
19
Potential in Th Fuel Cycle
Chemical Separation with CMK:Alcohol Hybrid yielding isotopically pure 233U
Figure by Andrew Nelson
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Conclusions and Future Directions
 Pa can be selectively extracted from the actinides with aliphatic alcohols

Unique complex formation

Extraction modeling
 Mesoporous carbon has potential for separations
 Further model solvent extraction behavior
 Access higher quantities of Protactinium for spectroscopic studies
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Acknowledgements

University of Iowa

Dr. Michael Schultz




Eric Eitrheim
Andy Nelson
Madeline Peterson
Dr. Tori Forbes





Daniel Unruh Josh de Groot
Ashini Jayasinghe
Madeline Basile
Maurice Payne

Eichrom Technologies, LLC

Idaho National Laboratory

Savannah River National Laboratory 22

Thank You! The 61st Annual Radiobioassay &
Radiochemical Measurements
Conference
October 25th- 30th, 2015.
Iowa City, IA