1
|
Tian C, Yamashita S, Kimura A, Obata Y, Yu H, Taguchi M. Hydroxyl radical scavenging and chemical repair capabilities of positively charged peptides (PCPs): a pulse radiolysis study. Free Radic Res 2024; 58:388-395. [PMID: 39113587 DOI: 10.1080/10715762.2024.2385342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/20/2024] [Accepted: 07/16/2024] [Indexed: 08/20/2024]
Abstract
Pulse radiolysis was employed to investigate fundamental radiation chemical reactions, which are essential in the radiation protection of DNA. Two positively charged peptides (PCPs), histidine-tyrosine-histidine (His-Tyr-His) and lysine-tyrosine-lysine (Lys-Tyr-Lys), as well as the amino acids that constitute them, were involved. The reaction rate constants for tyrosine (Tyr), histidine (His), lysine (Lys), His-Tyr-His, and Lys-Tyr-Lys with OH radicals (•OH) were (1.6 ± 0.3) × 1010, (9.0 ± 0.9) × 109, (1.4 ± 0.3) × 109, (1.8 ± 0.1) × 1010, and (1.0 ± 0.1) × 1010 M-1s-1, respectively, indicating that formation of peptide bond can affect the reaction of amino acids with •OH. Observed transient absorption spectra indicated a shielding effect of the His or Lys residues at both ends of the PCPs on the centrally located Tyr. The measurement of chemical repair capabilities using deoxyguanosine monophosphate (dGMP) as a model for DNA demonstrated that the reaction rate constants of Tyr, His-Tyr-His, and Lys-Tyr-Lys with dGMP radicals were (2.2 ± 0.5) × 108, (2.3 ± 0.1) × 108, and (3.3 ± 0.4) × 108 M-1s-1, respectively, implying that the presence of a positive charge may enhance the chemical repair process.
Collapse
Affiliation(s)
- Chaozhong Tian
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Shinichi Yamashita
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, Tokyo, Japan
- Nuclear Professional School, School of Engineering, The University of Tokyo, Naka-gun, Japan
| | - Atsushi Kimura
- National Institutes for Quantum Science and Technology (QST), Takasaki Institute for Advanced Quantum Science, Takasaki, Japan
| | - Yui Obata
- Nuclear Professional School, School of Engineering, The University of Tokyo, Naka-gun, Japan
| | - Hao Yu
- National Institutes for Quantum Science and Technology (QST), Takasaki Institute for Advanced Quantum Science, Takasaki, Japan
| | - Mitsumasa Taguchi
- National Institutes for Quantum Science and Technology (QST), Takasaki Institute for Advanced Quantum Science, Takasaki, Japan
| |
Collapse
|
2
|
Mezyk SP, Baxter M, Celis-Barros C, Grimes TS, Zalupski PR, Rae C, Zarzana CA, Cook AR, Horne GP. Effect of f-element complexation on the radiolysis of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). Dalton Trans 2024; 53:6881-6891. [PMID: 38407412 DOI: 10.1039/d4dt00424h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A systematic study of the impact on the chemical reactivity of the oxidising n-dodecane radical cation (RH˙+) with f-element complexed 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) has been undertaken utilizing time-resolved electron pulse radiolysis/transient absorption spectroscopy and high-level quantum mechanical calculations. Lanthanide ion complexed species, [Ln((HEH[EHP])2)3], exhibited vastly increased reactivity (over 10× faster) in comparison to the non-complexed ligand in n-dodecane solvent, whose rate coefficient was k = (4.66 ± 0.22) × 109 M-1 s-1. Similar reactivity enhancement was also observed for the corresponding americium ion complex, k = (5.58 ± 0.30) × 1010 M-1 s-1. The vastly increased reactivity of these f-element complexes was not due to simple increased diffusion-control of these reactions; rather, enhanced hole transfer mechanisms for the complexes were calculated to become energetically more favourable. Interestingly, the observed reactivity trend with lanthanide ion size was not linear; instead, the rate coefficients showed an initial increase (Lu to Yb) followed by a decrease (Tm to Ho), followed by another increase (Dy to La). This behaviour was excellently predicted by the calculated reaction volumes of these complexes. Complementary cobalt-60 gamma irradiations for select lanthanide complexes demonstrated that the measured kinetic differences translated to increased ligand degradation at steady-state timescales, affording ∼38% increase in ligand loss of a 1 : 1 [La((HEH[EHP])2)3] : HEH[EHP] ratio system.
Collapse
Affiliation(s)
- Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90804, USA.
| | - Makayla Baxter
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | | | - Travis S Grimes
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Peter R Zalupski
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Cathy Rae
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Christopher A Zarzana
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Andrew R Cook
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| |
Collapse
|
3
|
Miyagawa A, Hayashi N, Iwamoto H, Arai T, Nagatomo S, Miyazaki Y, Hasegawa K, Sano Y, Nakatani K. Kinetic analysis of mass transfer of Eu(III) in extractant-impregnated polymer-layered silica particle in multiple-ion distribution system. ANAL SCI 2024; 40:347-352. [PMID: 38044377 DOI: 10.1007/s44211-023-00462-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/01/2023] [Indexed: 12/05/2023]
Abstract
The Eu(III) distribution mechanism in single extractant-impregnated polymer-layered silica particle in a complex solution containing multiple lanthanide ions was investigated using fluorescence microspectroscopy, which was compared with the single-ion distribution system. The rate-determining step of the Eu(III) distribution was the reaction of Eu(III) with the two extractant molecules in the particle. The distribution mechanism and rate constants obtained in the multiple lanthanide ions-distribution system agreed with those of the single-ion distribution system.
Collapse
Affiliation(s)
- Akihisa Miyagawa
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Naoki Hayashi
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Hibiki Iwamoto
- Department of Material Science, Faculty of Engineering, Shibaura Institute of Technology, Toyosu, Tokyo, 135-8548, Japan
| | - Tsuyoshi Arai
- Department of Material Science, Faculty of Engineering, Shibaura Institute of Technology, Toyosu, Tokyo, 135-8548, Japan
| | - Shigenori Nagatomo
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Yasunori Miyazaki
- Department of Reprocessing Technology Development, Nuclear Fuel Cycle Engineering Labolatories, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, 319-1194, Japan
| | - Kenta Hasegawa
- Department of Reprocessing Technology Development, Nuclear Fuel Cycle Engineering Labolatories, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, 319-1194, Japan
| | - Yuichi Sano
- Department of Reprocessing Technology Development, Nuclear Fuel Cycle Engineering Labolatories, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, 319-1194, Japan
| | - Kiyoharu Nakatani
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan.
| |
Collapse
|
4
|
Rotermund BM, Sperling JM, Horne GP, Beck NB, Wineinger HB, Bai Z, Celis-Barros C, Gomez Martinez D, Albrecht-Schönzart TE. Co-Crystallization of Plutonium(III) and Plutonium(IV) Diglycolamides with Pu(III) and Pu(IV) Hexanitrato Anions: A Route to Redox Variants of [Pu III,IV(DGA) 3][Pu III,IV(NO 3) 6] x. Inorg Chem 2023; 62:12905-12912. [PMID: 37523261 DOI: 10.1021/acs.inorgchem.3c01590] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
N,N,N',N'-tetramethyl diglycolamide (TMDGA), a methylated variant of the diglycolamide extractants being proposed as curium holdback reagents in advanced used nuclear fuel reprocessing technologies, has been crystallized with plutonium, a transuranic actinide that has multiple accessible oxidation states. Two plutonium TMDGA complexes, [PuIII(TMDGA)3][PuIII(NO3)6] and[PuIV(TMDGA)3][PuIV(NO3)6]2·0.75MeOH, were crystallized through solvent diffusion of a reaction mixture containing plutonium(III) nitrate and TMDGA. The sample was then partially oxidized by air to yield [PuIV(TMDGA)3][PuIV(NO3)6]2·0.75MeOH. Single-crystal X-ray diffraction reveals that the multinuclear systems crystallize with hexanitrato anionic species, providing insight into the first solid-state isolation of the elusive trivalent plutonium hexanitrato species. Crystallography data show a change in geometry around the TMDGA metal center from Pu3+ to Pu4+, with the symmetry increasing approximately from C4v to D3h. These complexes provide a rare opportunity to investigate the bond metrics of plutonium in two different oxidation states with similar coordination environments. Further, these new structures provide insight into the potential chemical and structural differences arising from the radiation-induced formation of transient tetravalent curium oxidation states in used nuclear fuel reprocessing streams.
Collapse
Affiliation(s)
- Brian M Rotermund
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph M Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Nicholas B Beck
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Hannah B Wineinger
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Zhuanling Bai
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Cristian Celis-Barros
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Daniela Gomez Martinez
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Nuclear Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| |
Collapse
|
5
|
Wang Y, Mezyk SP, McLachlan JR, Grimes TS, Zalupski PR, O'Bryan HMT, Cook AR, Abergel RJ, Horne GP. Radiolytic Evaluation of 3,4,3-LI(1,2-HOPO) in Aqueous Solutions. J Phys Chem B 2023; 127:3931-3938. [PMID: 37084416 DOI: 10.1021/acs.jpcb.3c01469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
The octadentate hydroxypyridinone ligand 3,4,3-LI(1,2-HOPO) (abbreviated as HOPO) has been identified as a promising candidate for both chelation and f-element separation technologies, two applications that require optimal performance in radiation environments. However, the radiation robustness of HOPO is currently unknown. Here, we employ a combination of time-resolved (electron pulse) and steady-state (alpha self-radiolysis) irradiation techniques to elucidate the basic chemistry of HOPO and its f-element complexes in aqueous radiation environments. Chemical kinetics were measured for the reaction of HOPO and its Nd(III) ion complex ([NdIII(HOPO)]-) with key aqueous radiation-induced radical transients (eaq-, H• atom, and •OH and NO3• radicals). The reaction of HOPO with the eaq- is believed to proceed via reduction of the hydroxypyridinone moiety, while transient adduct spectra indicate that reactions with the H• atom and •OH and NO3• radicals proceeded by addition to HOPO's hydroxypyridinone rings, potentially allowing for the generation of an extensive suite of addition products. Complementary steady-state 241Am(III)-HOPO complex ([241AmIII(HOPO)]-) irradiations showed the gradual release of 241Am(III) ions with increasing alpha dose up to 100 kGy, although complete ligand destruction was not observed.
Collapse
Affiliation(s)
- Yufei Wang
- Department of Nuclear Engineering, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California 90804, United States
| | - Jeffrey R McLachlan
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Travis S Grimes
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
| | - Peter R Zalupski
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
| | - Hailie M T O'Bryan
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew R Cook
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rebecca J Abergel
- Department of Nuclear Engineering, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, Idaho Falls, Idaho 83415, United States
| |
Collapse
|
6
|
Conrad JK, Mezyk SP, Isherwood LH, Baidak A, Pilgrim CD, Whittaker D, Orr RM, Pimblott SM, Horne GP. Gamma Radiation-Induced Degradation of Acetohydroxamic Acid (AHA) in Aqueous Nitrate and Nitric Acid Solutions Evaluated by Multiscale Modelling. Chemphyschem 2023; 24:e202200749. [PMID: 36470592 DOI: 10.1002/cphc.202200749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/11/2022] [Indexed: 12/12/2022]
Abstract
Acetohydroxamic acid (AHA) has been proposed for inclusion in advanced, single-cycle, used nuclear fuel reprocessing solvent systems for the reduction and complexation of plutonium and neptunium ions. For this application, a detailed description of the fundamental degradation of AHA in dilute aqueous nitric acid is required. To this end, we present a comprehensive, multiscale computer model for the coupled radiolytic and hydrolytic degradation of AHA in aqueous sodium nitrate and nitric acid solutions. Rate coefficients for the reactions of AHA and hydroxylamine (HA) with the oxidizing nitrate radical were measured for the first time using electron pulse radiolysis and used as inputs for the kinetic model. The computer model results are validated by comparison to experimental data from steady-state gamma ray irradiations, for which the agreement is excellent. The presented model accurately predicts the yields of the major degradation products of AHA: acetic acid, HA, nitrous oxide, and molecular hydrogen.
Collapse
Affiliation(s)
- Jacy K Conrad
- Center for Radiation Chemistry Research, Idaho National Laboratory, 1955 N. Fremont Ave., 83415, Idaho Falls, ID, USA
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd, 90840, Long Beach, CA, USA
| | - Liam H Isherwood
- Dalton Cumbrian Facility, The University of Manchester, West Lakes Science Park, CA24 3HA, Moor Row, U. K.,Department of Chemistry, The University of Manchester, Oxford Rd, M13 9PL, Manchester, U.K
| | - Aliaksandr Baidak
- Dalton Cumbrian Facility, The University of Manchester, West Lakes Science Park, CA24 3HA, Moor Row, U. K.,Department of Chemistry, The University of Manchester, Oxford Rd, M13 9PL, Manchester, U.K
| | - Corey D Pilgrim
- Center for Radiation Chemistry Research, Idaho National Laboratory, 1955 N. Fremont Ave., 83415, Idaho Falls, ID, USA
| | - Daniel Whittaker
- National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale, CA20 1PG, Cumbria, U.K
| | - Robin M Orr
- National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale, CA20 1PG, Cumbria, U.K
| | - Simon M Pimblott
- Center for Radiation Chemistry Research, Idaho National Laboratory, 1955 N. Fremont Ave., 83415, Idaho Falls, ID, USA
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, 1955 N. Fremont Ave., 83415, Idaho Falls, ID, USA
| |
Collapse
|
7
|
Horne GP, Rotermund BM, Grimes TS, Sperling JM, Meeker DS, Zalupski PR, Beck N, Huffman ZK, Martinez DG, Beshay A, Peterman DR, Layne BH, Johnson J, Cook AR, Albrecht-Schönzart TE, Mezyk SP. Transient Radiation-Induced Berkelium(III) and Californium(III) Redox Chemistry in Aqueous Solution. Inorg Chem 2022; 61:10822-10832. [PMID: 35776877 DOI: 10.1021/acs.inorgchem.2c01106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the significant impact of radiation-induced redox reactions on the accessibility and lifetimes of actinide oxidation states, fundamental knowledge of aqueous actinide metal ion radiation chemistry is limited, especially for the late actinides. A quantitative understanding of these intrinsic radiation-induced processes is essential for investigating the fundamental properties of these actinides. We present here a picosecond electron pulse reaction kinetics study into the radiation-induced redox chemistry of trivalent berkelium (Bk(III)) and californium (Cf(III)) ions in acidic aqueous solutions at ambient temperature. New and first-of-a-kind, second-order rate coefficients are reported for the transient radical-induced reduction of Bk(III) and Cf(III) by the hydrated electron (eaq-) and hydrogen atom (H•), demonstrating a significant reactivity (up to 1011 M-1 s-1) indicative of a preference of these metals to adopt divalent states. Additionally, we report the first-ever second-order rate coefficients for the transient radical-induced oxidation of these elements by a reaction with hydroxyl (•OH) and nitrate (NO3•) radicals, which also exhibited fast reactivity (ca. 108 M-1 s-1). Transient Cf(II), Cf(IV), and Bk(IV) absorption spectra are also reported. Overall, the presented data highlight the existence of rich, complex, intrinsic late actinide radiation-induced redox chemistry that has the potential to influence the findings of other areas of actinide science.
Collapse
Affiliation(s)
- Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Brian M Rotermund
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Travis S Grimes
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Joseph M Sperling
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - David S Meeker
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States.,Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Peter R Zalupski
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Nicholas Beck
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Zachary K Huffman
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Daniela Gomez Martinez
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Andrew Beshay
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach, California 90840-9507, United States
| | - Dean R Peterman
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415, United States
| | - Bobby H Layne
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jason Johnson
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Andrew R Cook
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach, California 90840-9507, United States
| |
Collapse
|
8
|
Kimberlin A, Saint-Louis G, Guillaumont D, Camès B, Guilbaud P, Berthon L. Effect of Metal Complexation on Diglycolamides Radiolysis: A Comparison between Ex-Situ Gamma and In-Situ Alpha Irradiation. Phys Chem Chem Phys 2022; 24:9213-9228. [DOI: 10.1039/d1cp05731f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radiolytic degradation is an important aspect to consider when developping a ligand or a complexant for radionucleides. Diglycolamide extractants (DGAs) have been playing an important role in many partition processes...
Collapse
|
9
|
Celis Barros C, Pilgrim CD, Cook AR, Mezyk SP, Grimes TS, Horne GP. Influence of uranyl complexation on the reaction kinetics of the dodecane radical cation with used nuclear fuel extraction ligands (TBP, DEHBA, and DEHiBA). Phys Chem Chem Phys 2021; 23:24589-24597. [PMID: 34710211 DOI: 10.1039/d1cp03797h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Specialized extractant ligands - such as tri-butyl phosphate (TBP), N,N-di-(2-ethylhexyl)butyramide (DEHBA), and N,N-di-2-ethylhexylisobutryamide (DEHiBA) - have been developed for the recovery of uranium from used nuclear fuel by reprocessing solvent extraction technologies. These ligands must function in the presence of an intense multi-component radiation field, and thus it is critical that their radiolytic behaviour be thoroughly evaluated. This is especially true for their metal complexes, where there is negligible information on the influence of complexation on radiolytic reactivity, despite the prevalence of metal complexes in used nuclear fuel reprocessing solvent systems. Here we present a kinetic investigation into the effect of uranyl (UO22+) complexation on the reaction kinetics of the dodecane radical cation (RH˙+) with TBP, DEHBA, and DEHiBA. Complexation had negligible effect on the reaction of RH˙+ with TBP, for which a second-order rate coefficient (k) of (1.3 ± 0.1) × 1010 M-1 s-1 was measured. For DEHBA and DEHiBA, UO22+ complexation afforded an increase in their respective rate coefficients: k(RH˙+ + [UO2(NO3)2(DEHBA)2]) = (2.5 ± 0.1) × 1010 M-1 s-1 and k(RH˙+ + [UO2(NO3)2(DEHiBA)2]) = (1.6 ± 0.1) × 1010 M-1 s-1. This enhancement with complexation is indicative of an alternative RH˙+ reaction pathway, which is more readily accessible for [UO2(NO3)2(DEHBA)2] as it exhibited a much larger kinetic enhancement than [UO2(NO3)2(DEHiBA)2], 2.6× vs. 1.4×, respectively. Complementary quantum mechanical calculations suggests that the difference in reaction kinetic enhancement between TBP and DEHBA/DEHiBA is attributed to a combination of reaction pathway (electron/hole transfer vs. proton transfer) energetics and electron density distribution, wherein attendant nitrate counter anions effectively 'shield' TBP from RH˙+ electron transfer processes.
Collapse
Affiliation(s)
- Cristian Celis Barros
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA.
| | - Corey D Pilgrim
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415, USA.
| | - Andrew R Cook
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach, California, 90840-9507, USA
| | - Travis S Grimes
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415, USA.
| | - Gregory P Horne
- Center for Radiation Chemistry Research, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415, USA.
| |
Collapse
|
10
|
Horne GP, Grimes TS, Zalupski PR, Meeker DS, Albrecht-Schönzart TE, Cook AR, Mezyk SP. Curium(iii) radiation-induced reaction kinetics in aqueous media. Dalton Trans 2021; 50:10853-10859. [PMID: 34296716 DOI: 10.1039/d1dt01268a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Insight into the effects of radiolytic processes on the actinides is critical for advancing our understanding of their solution chemistry because the behaviour of these elements cannot be easily separated from the influence of their inherent radiation field. However, minimal information exists on the radiation-induced redox behaviour of curium (Cm), a key trivalent transuranic element present in used nuclear fuel and frequently used as an alpha radiation source. Here we present a kinetic study on the aqueous redox reactions of Cm(iii) with radicals generated through the radiolysis of aqueous media. In particular, we probe reaction kinetics in nitric acid solutions that are used as the aqueous phase component of used nuclear fuel reprocessing solvent systems. Second-order rate coefficients (k) were measured for the reaction of Cm(iii) with the hydrated electron (eaq-, k = (1.25 ± 0.03) × 1010 M-1 s-1), hydrogen atom (H˙, k = (5.16 ± 0.37) × 108 M-1 s-1), hydroxyl radical (˙OH, k = (1.69 ± 0.24) × 109 M-1 s-1), and nitrate radical (NO3˙, k = (4.83 ± 0.09) × 107 M-1 s-1). Furthermore, the first-ever Cm(ii) absorption spectrum (300-700 nm) is also reported. These kinetic data dispel the status quo notion of Cm(iii) possessing little to no redox chemistry in aqueous solution, and suggest that the resulting Cm(ii) and Cm(iv) transients could exist in irradiated aqueous solutions and be available to undergo subsequent redox chemistry with other solutes.
Collapse
Affiliation(s)
- Gregory P Horne
- Idaho National Laboratory, Center for Radiation Chemistry Research, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Travis S Grimes
- Idaho National Laboratory, Center for Radiation Chemistry Research, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - Peter R Zalupski
- Idaho National Laboratory, Center for Radiation Chemistry Research, Idaho Falls, ID, P.O. Box 1625, 83415, USA.
| | - David S Meeker
- Idaho National Laboratory, Center for Radiation Chemistry Research, Idaho Falls, ID, P.O. Box 1625, 83415, USA. and Florida State University, Department of Chemistry and Biochemistry, Tallahassee, FL 32306, USA
| | | | - Andrew R Cook
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach California 90840-9507, USA.
| |
Collapse
|