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El Monjid A, Szenknect S, Mesbah A, Hunault MOJY, Menut D, Clavier N, Dacheux N. Incorporation of U(IV) in monazite-cheralite ceramics under oxidizing and inert atmospheres. Dalton Trans 2024; 53:2252-2264. [PMID: 38193888 DOI: 10.1039/d3dt03251e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
This work is the first attempt to prepare Nd1-xCaxUxPO4 monazite-cheralite with 0 < x ≤ 0.1 by a wet chemistry method. This method relies on the precipitation under hydrothermal conditions (T = 110 °C for four days) of the Nd1-xCaxUxPO4·nH2O rhabdophane precursor, followed by its thermal conversion for 6 h at 1100 °C in air or Ar atmosphere. The optimized synthesis protocol led to the incorporation of U and Ca in the rhabdophane structure. After heating at 1100 °C for 6 h in air, single-phase monazite-cheralite samples were obtained. However, α-UP2O7 was identified as a secondary minor phase in the samples heated under Ar atmosphere. The U speciation in the samples converted in an oxidising atmosphere was carefully characterized using synchrotron radiation by combining HERFD-XANES and XRD. These results showed the presence of a minor secondary phase containing hexavalent uranium and phosphate with a stoichiometry of U : P = 0.78. This highly labile uranyl phosphate phase incorporated 21 mol% of the uranium initially precipitated with the rhabdophane precursor. This phase was completely removed by a washing protocol. Thus, single-phase monazite-cheralite was obtained through the wet chemistry route described in this work with a maximum U loading of x = 0.08.
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Affiliation(s)
- Alison El Monjid
- ICSM, Univ. Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols/Cèze, France.
| | - Stéphanie Szenknect
- ICSM, Univ. Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols/Cèze, France.
| | - Adel Mesbah
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, F-69626 Villeurbanne, France
| | | | - Denis Menut
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Nicolas Clavier
- ICSM, Univ. Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols/Cèze, France.
| | - Nicolas Dacheux
- ICSM, Univ. Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols/Cèze, France.
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Zhao X, Wang W, Teng Y, Li Y, Ma X, Liu Y, Ahuja R, Luo W, Zhang Z. Incorporation of Th 4+ and Sr 2+ into Rhabdophane/Monazite by Wet Chemistry: Structure and Phase Stability. Inorg Chem 2023; 62:15605-15615. [PMID: 37695943 DOI: 10.1021/acs.inorgchem.3c02253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Rhabdophane is an important permeable reactive barrier to enrich radionuclides from groundwater and has been envisaged to host radionuclides in the backend of the nuclear fuel cycle. However, understanding of how An4+ and Sr2+ precipitate into rhabdophane by wet chemistry has not been resolved. In this work, Th4+ and Sr2+ incorporation in the rhabdophane/monazite structure as La1-2xSrxThxPO4·nH2O solid solutions is successfully achieved in the acid solution at 90 °C. Some specific issues such as lattice occupation of Th4+ and Sr2+, precipitation reaction kinetics, and crystal growth affected by starting stoichiometry are discussed in detail, along with investigating the chemical stability of La1-2xSrxThxPO4·nH2O precipitations and associated La1-2xSrxThxPO4 monazite. The results reveal that the excess of Sr2+ appears to be a prevailing factor with a suggested initial Sr: Th ≥ 2 to obtain the stability domain of La1-2xSrxThxPO4·nH2O (x = 0∼ 0.1). A rapid ion removal associated with a nucleation process has been observed within 8 h, and Th4+ can be removed more than 98% after 24 h in 0.01 mol/L solutions. From structural energetics based on density functional theory, the lattice occupation of Th4+ and Sr2+ is energetically favorable in nonhydrated lattice sites of [LaO8], although two-thirds of lattice sites are associated with [LaO8·H2O] hydrated sites. Intriguingly, the crystal transformation from rhabdophane to monazite associated with the transformation from [SrO8] to [SrO9] polyhedra can greatly improve the leaching stability of Sr2+.
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Affiliation(s)
- Xiaofeng Zhao
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Weipeng Wang
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
| | - Yuancheng Teng
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Yuxiang Li
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Xue Ma
- State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China
| | - Yang Liu
- China Aerodynamics Research and Development Center, Mianyang 621000, PR China
| | - Rajeev Ahuja
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Wei Luo
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Zhengjun Zhang
- The Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China
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Shelyug A, Rafiuddin MR, Mesbah A, Clavier N, Szenknect S, Dacheux N, Guo X, Navrotsky A. Effect of Annealing on Structural and Thermodynamic Properties of ThSiO 4-ErPO 4 Xenotime Solid Solution. Inorg Chem 2021; 60:12020-12028. [PMID: 34328730 DOI: 10.1021/acs.inorgchem.1c01137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of annealing on structural and thermochemical properties of a thorite-xenotime solid solution Th1-xErx(SiO4)1-x(PO4)x was assessed. The samples synthesized at low temperatures and stored at room temperature for 2 years retained their tetragonal structures. This structure was also maintained after heating to 1100 °C. During annealing, the structure lost water and exsolved some thorianite phases. The thermodynamic parameters did not change much after annealing, suggesting that xenotime was not a low-temperature metastable phase but rather a stable structure able to withstand elevated temperatures regardless of the thorium content. The solid solution exhibited subregular behavior with the Margules function W(x) = (73.1 ± 20.1) - (125.7 ± 49.8)·x.
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Affiliation(s)
- Anna Shelyug
- Institute of Solid State Chemistry, Yekaterinburg 620990, Russia
| | | | - Adel Mesbah
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France.,Institut de Recherches sur la Catalyse et l'Environnement de Lyon, IRCELYON, UMR5256, CNRS, Univ Lyon, Université Lyon 1, 2 Avenue Albert Einstein, Villeurbanne Cedex 69626, France
| | - Nicolas Clavier
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Stéphanie Szenknect
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Nicolas Dacheux
- ICSM, Univ Montpellier, CNRS, CEA, ENSCM, Site de Marcoule, Bagnols-sur-Cèze 30207, France
| | - Xiaofeng Guo
- Department of Chemistry and Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99164, United States
| | - Alexandra Navrotsky
- School of Molecular Sciences a Center for Materials of the Universe, Arizona State University, Tempe, Arizona 85287, United States
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