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Dunbar JR, Jensen MP. Influence of Di- n-butyl Phosphoric Acid on Cerium Redox and Speciation in Tri- n-butyl Phosphate. Inorg Chem 2024; 63:12839-12848. [PMID: 38949275 DOI: 10.1021/acs.inorgchem.4c01309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The effects of simulated radiolytic degradation of tri-n-butyl phosphate (TBP) on the chemical speciation of cerium were studied by spectrophotometry and electrochemistry of TBP solutions containing increasing amounts of di-n-butyl phosphoric acid (HDBP), a common degradation product of TBP. Tetravalent cerium was found to exchange coordinated nitrate for the dibutyl phosphate anion, forming dinuclear complexes of the formula (CeOCe)(NO3)(6-d)(DBP)d·3TBP (d = 0-3). Compared to Ce(IV), Ce(III) was complexed less strongly by HDBP in TBP, but HDBP displaced both nitrate and TBP to form the series of mononuclear complexes Ce(NO3)(3-d)(HDBP·DBP)d·(3-d)TBP (d = 0-3). Dibutyl phosphate coordination caused large negative shifts in the Ce(IV/III) reduction potential in TBP, indicating a strong stabilization of the tetravalent state. Electrochemical investigation of the reduction of Ce(IV) in TBP revealed it to be a two-electron process in accordance with the dinuclear nature of the organic-phase Ce(IV) complexes. The diffusion coefficients of the d = 0 dinuclear Ce(IV)-nitrate-TBP complex and mononuclear Ce(III)-nitrate-TBP complex in TBP equilibrated with 7 M HNO3 were determined to be (1.16 ± 0.06) × 10-7 cm2/s and (1.9 ± 0.4) × 10-7 cm2/s, respectively, which also is consistent with the larger molecular volume of the dinuclear Ce(IV) complexes.
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Affiliation(s)
- Joshua R Dunbar
- Chemistry Department, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Mark P Jensen
- Chemistry Department, Colorado School of Mines, Golden, Colorado 80401, United States
- Nuclear Science & Engineering Program, Colorado School of Mines, Golden, Colorado 80401, United States
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3
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Bertelsen ER, Antonio MR, Jensen MP, Shafer JC. Electrochemistry of PUREX: R is for reduction and ion transfer. SOLVENT EXTRACTION AND ION EXCHANGE 2021. [DOI: 10.1080/07366299.2021.1920674] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Erin R. Bertelsen
- Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
| | - Mark R. Antonio
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois, USA
| | - Mark P. Jensen
- Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
- Nuclear Science and Engineering Program, Colorado School of Mines, Golden, Colorado, USA
| | - Jenifer C. Shafer
- Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
- Nuclear Science and Engineering Program, Colorado School of Mines, Golden, Colorado, USA
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4
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Feuchter H, Duval S, Volkringer C, Ouf FX, Rigollet L, Cantrel L, De Mendonca Andrade M, Salm F, Lavalette C, Loiseau T. Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process. ACS OMEGA 2019; 4:12896-12904. [PMID: 31460416 PMCID: PMC6682031 DOI: 10.1021/acsomega.9b00746] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Modeling of plutonium(IV) behavior during an accidental fire in a reprocessing plant was considered using various non-radioactive metallic surrogates. Among those elements, cerium(IV) was supposed to be a suitable candidate due to possible formation of a complex with TPB, but its extractability and stability have not been studied previously under representative plutonium uranium reduction extraction (PUREX) conditions. In this work, we investigated the chemical analogy between cerium(IV) and plutonium(IV) in this extractive process and combustion thereof. Distribution ratios are reported for acidities of 1-4 mol L-1 in equal volumes of nitric acid and a 30:70 mixture of tributylphosphate and hydrogenated tetrapropylene. The influences of light, temperature, and extraction time were studied by UV-vis spectroscopy. The results showed that cerium(IV) is extracted quantitatively but is reduced over time to cerium(III) in the organic mixture. Spectrophotometric investigations of this reaction kinetics revealed an apparent rate constant k of 0.021 ± 0.002 mol0.5 L0.5 min-1 at 298 K and an apparent fractional reaction order of 0.5. The activation energy of this reduction was found to be around 82 ± 2 kJ mol-1 by the Arrhenius plot method. The combustion of mono- and biphasic solutions prepared with a cerium(IV) concentration of 10 g L-1 revealed that the extracted complexes, Ce2O·6NO3·3TBP(org) or Ce4O4·8NO3·6TBP(org), are reduced during the combustion. Compositions of the resulting ashes and soot were analyzed and highlighted the presence of pyrophosphates and polycyclic aromatic hydrocarbons, with some traces of cerium. Ce(IV) is not suitable to represent Pu(IV) from a chemical point of view in HNO3/TBP-HTP solutions.
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Affiliation(s)
- Hervé Feuchter
- Université
de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181—UCCS—Unité
de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Sylvain Duval
- Université
de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181—UCCS—Unité
de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Christophe Volkringer
- Université
de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181—UCCS—Unité
de Catalyse et Chimie du Solide, F-59000 Lille, France
- Institut
Universitaire de France (IUF), 1, rue Descartes, 75231 Paris cedex 05, France
| | - François-Xavier Ouf
- Institut
de Radioprotection et de Sûreté Nucléaire (IRSN),
PSN-RES/SCA, PSN-RES/SA2I, PSN-RES/SEREX, Gif-Sur-Yvette 91192, France
| | - Laurence Rigollet
- Institut
de Radioprotection et de Sûreté Nucléaire (IRSN),
PSN-RES/SCA, PSN-RES/SA2I, PSN-RES/SEREX, Gif-Sur-Yvette 91192, France
| | - Laurent Cantrel
- Institut
de Radioprotection et de Sûreté Nucléaire (IRSN),
PSN-RES/SCA, PSN-RES/SA2I, PSN-RES/SEREX, Gif-Sur-Yvette 91192, France
| | - Matheus De Mendonca Andrade
- Institut
de Radioprotection et de Sûreté Nucléaire (IRSN),
PSN-RES/SCA, PSN-RES/SA2I, PSN-RES/SEREX, Gif-Sur-Yvette 91192, France
| | - François Salm
- Institut
de Radioprotection et de Sûreté Nucléaire (IRSN),
PSN-RES/SCA, PSN-RES/SA2I, PSN-RES/SEREX, Gif-Sur-Yvette 91192, France
| | | | - Thierry Loiseau
- Université
de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181—UCCS—Unité
de Catalyse et Chimie du Solide, F-59000 Lille, France
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5
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Bahri MA, Ruas A, Labbé E, Moisy P. Electrochemical characterization of plutonium in n-tributyl phosphate. Dalton Trans 2017; 46:4943-4949. [DOI: 10.1039/c6dt04765c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrochemical properties of plutonium (iv and vi) extracted in tributylphosphate from nitric acid aqueous solutions are explored.
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Affiliation(s)
- M. A. Bahri
- CEA
- Nuclear Energy Division
- Radiochemistry and Processes Department
- F-30207 Bagnols sur Cèze
- France
| | - A. Ruas
- CEA
- Nuclear Energy Division
- Radiochemistry and Processes Department
- F-30207 Bagnols sur Cèze
- France
| | - E. Labbé
- École Normale Supérieure-PSL Research University
- Département de Chimie
- Sorbonne Universités
- UPMC Univ. Paris 6
- UMR 8640 PASTEUR
| | - P. Moisy
- CEA
- Nuclear Energy Division
- Radiochemistry and Processes Department
- F-30207 Bagnols sur Cèze
- France
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6
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Antonio MR, Ellis RJ, Estes SL, Bera MK. Structural insights into the multinuclear speciation of tetravalent cerium in the tri-n-butyl phosphate–n-dodecane solvent extraction system. Phys Chem Chem Phys 2017; 19:21304-21316. [DOI: 10.1039/c7cp03350h] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Macroscopic phase behaviors in the liquid–liquid extraction are explained by microscopic, reverse micellar fluid structures containing tetranuclear Ce(iv) clusters revealed by use of X-ray spectroscopy and scattering of the light and dense organic phases.
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Affiliation(s)
- Mark R. Antonio
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
| | - Ross J. Ellis
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
| | - Shanna L. Estes
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
| | - Mrinal K. Bera
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
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7
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Ellis RJ, Bera MK, Reinhart B, Antonio MR. Trapped in the coordination sphere: nitrate ion transfer driven by the cerium(iii/iv) redox couple. Phys Chem Chem Phys 2016; 18:31254-31259. [DOI: 10.1039/c6cp06528g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrochemical transfer of nitrate anions between oil and water phases—driven by the reduction and oxidation of cerium coordination complexes in oil phases—provides a new entry into chemical separations where an electrode potential tunes solute transfer between phases by ‘trapping’ the migrating anion on the cerium cation.
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Affiliation(s)
- Ross J. Ellis
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
| | - Mrinal K. Bera
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
| | | | - Mark R. Antonio
- Chemical Sciences and Engineering Division
- Argonne National Laboratory
- Argonne
- USA
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