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Fang Q, Tan Y, Yan R, Zhang D, Li M, Wu X, Hua Y, Xue W, Wang R. Insights into the long-term immobilization performances and mechanisms of CMC-Fe 0/FeS with different sulfur sources for uranium under anoxic and oxic aging. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120157. [PMID: 38295639 DOI: 10.1016/j.jenvman.2024.120157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/04/2024] [Accepted: 01/20/2024] [Indexed: 02/18/2024]
Abstract
Nanoscale zerovalent iron (Fe0)-based materials have been demonstrated to be a effective method for the U(VI) removal. However, limited research has been conducted on the long-term immobilization efficiency and mechanism of Fe0-based materials for U(VI), which are essential for achieving safe handling and disposal of U(VI) on a large scale. In this study, the prepared carboxymethyl cellulose (CMC) and sulfurization dual stabilized Fe0 (CMC-Fe0/FeS) exhibited excellent long-term immobilization performances for U(VI) under both anoxic and oxic conditions, with the immobilization efficiencies were respectively reached over 98.0 % and 94.8 % after 180 days of aging. Most importantly, different from the immobilization mechanisms of the fresh CMC-Fe0/FeS for U(VI) (the adsorption effect of -COOH and -OH groups, coordination effect with sulfur species, as well as reduction effect of Fe0), the re-mobilized U(VI) were finally re-immobilized by the formed FeOOH and Fe3O4 on the aged CMC-Fe0/FeS. Under anoxic conditions, more Fe3O4 was produced, which may be the main reason for the long-term immobilization U(VI). Under oxic conditions, the production of Fe3O4 and FeOOH were relatively high, which both played significant roles in re-immobilizing U(VI) through surface complexation, reduction and incorporation effects.
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Affiliation(s)
- Qi Fang
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Yanling Tan
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Ran Yan
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - De Zhang
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Mi Li
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Xiaoyan Wu
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Yilong Hua
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China
| | - Wenjing Xue
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Rongzhong Wang
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan, 421001, China.
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Katheras AS, Karalis K, Krack M, Scheinost AC, Churakov SV. Stability and Speciation of Hydrated Magnetite {111} Surfaces from Ab Initio Simulations with Relevance for Geochemical Redox Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:935-946. [PMID: 38133817 DOI: 10.1021/acs.est.3c07202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Magnetite is a common mixed Fe(II,III) iron oxide in mineral deposits and the product of (anaerobic) iron corrosion. In various Earth systems, magnetite surfaces participate in surface-mediated redox reactions. The reactivity and redox properties of the magnetite surface depend on the surface speciation, which varies with environmental conditions. In this study, Kohn-Sham density functional theory (DFT + U method) was used to examine the stability and speciation of the prevalent magnetite crystal face {111} in a wide range of pH and Eh conditions. The simulations reveal that the oxidation state and speciation of the surface depend strongly on imposed redox conditions and, in general, may differ from those of the bulk state. Corresponding predominant phase diagrams for the surface speciation and structure were calculated from first principles. Furthermore, classical molecular dynamics simulations were conducted investigating the mobility of water near the magnetite surface. The obtained knowledge of the surface structure and oxidation state of iron is essential for modeling retention of redox-sensitive nuclides.
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Affiliation(s)
- Anita S Katheras
- Institute of Geological Sciences, University of Bern, CH-3012 Bern, Switzerland
| | | | - Matthias Krack
- Laboratory for Materials Simulations (LMS), Paul Scherrer Institute (PSI), CH-5232 Villigen PSI, Switzerland
| | - Andreas C Scheinost
- The Rossendorf Beamline (BM20), European Synchrotron Radiation Lab, FR-38043 Grenoble, France
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, DE-01328 Dresden-Rossendorf, Germany
| | - Sergey V Churakov
- Institute of Geological Sciences, University of Bern, CH-3012 Bern, Switzerland
- Laboratory for Waste Management (LES), Paul Scherrer Institute (PSI), CH-5232 Villigen PSI, Switzerland
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Kang M, Kang Y, Wu H, Qin D, Dai C, Wang J. The redox reactions of U(VI)/UO 2 on Tamusu claystone: Effects of Fe 2+/Fe 3+ and organic matters. CHEMOSPHERE 2024; 348:140754. [PMID: 37995974 DOI: 10.1016/j.chemosphere.2023.140754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/06/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023]
Abstract
The claystone-based Tamusu area in the Bayingebi Basin, Inner Mongolia, is preselected as a China's high-level radioactive waste (HLRW) repository site. This study investigated the redox reactions of U(VI)/UO2 on Tamusu claystone. Five Tamusu claystone samples collected from boreholes Tzk1 and Tzk2 at different depths were used for batch experiments at pH ∼5.0, ∼7.0, and ∼9.0. These claystones contain considerable amounts of organic matters and Fe2+-containing minerals such as pyrite, fluorannite, and ankerite. Results showed that aqueous U(VI) could be partially reduced to U(IV) and/or U(V)-containing precipitates (U3O8, U4O9, etc.) by these Tamusu claystones, and the reaction is more favorable under acidic condition. We proposed that leaching of the structural Fe2+ followed by surface adsorption and interface reaction, is the primary mechanism responsible for U(VI) reduction. Under alkaline condition, organic matters might dominate the partial reduction of aqueous U(VI). Besides, the phosphorus-containing spots on Tamusu claystone surfaces are the reactive sites for U aggregation, implying the possible formation of U(VI)- and/or U(IV)-phosphate minerals. It is important to note that, due to the presence of minor Fe3+ in Tamusu claystones, the high-purity UO2 could undergo partial oxidation to U4O9 and/or U3O8. Therefore, insoluble UO2+x (0 < x ≤ 0.67) is proposed to be the most thermodynamically stable form in Tamusu claystone. This study enhances our comprehension of the essential geochemical processes of uranium in claystone surroundings, but also offers crucial information for the safety evaluation of China's HLRW repository.
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Affiliation(s)
- Mingliang Kang
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China.
| | - Yixiao Kang
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Hanyu Wu
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Danwen Qin
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Chaocheng Dai
- College of Earth Sciences, East China University of Technology, Nanchang, 330013, China
| | - Ju Wang
- Beijing Research Institute of Uranium Geology, Beijing, 100029, China
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Zhang X, Zhang J, Peng Y, Wu X, Li M, Wen H, Sun Z, Ye J, Hua Y. Synergistic removal of glyphosate and U(VI) from aqueous solution by goethite: adsorption behaviour and mechanism. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08223-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Chen Z, Wang S, Hou H, Chen K, Gao P, Zhang Z, Jin Q, Pan D, Guo Z, Wu W. China's progress in radionuclide migration study over the past decade (2010-2021): Sorption, transport and radioactive colloid. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.02.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Wu H, Chen J, Su Z, Ma B, Ji Y, Lin S, Xu D, Kang M. Insight into the adsorption of europium(III) on muscovite and phlogopite: Effects of pH, electrolytes, humic substances and mica structures. CHEMOSPHERE 2021; 282:131087. [PMID: 34119726 DOI: 10.1016/j.chemosphere.2021.131087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 05/23/2021] [Accepted: 05/29/2021] [Indexed: 06/12/2023]
Abstract
Europium(III), i.e., Eu(III), is chemically analogous to the trivalent lanthanides (Ln) and actinides (An). A good understanding of the adsorption behaviour of Eu(III) on mica group minerals is critical to the safety evaluation of the radioactive contamination. Nevertheless, the structural complexity of micaceous minerals makes it difficult to draw a consistent conclusion in the study of Eu(III) migration. In this work, we contrastively studied Eu(III) adsorption on dioctahedral muscovite and trioctahedral phlogopite as functions of pH, ionic strength, background electrolytes, interaction sequence, and fulvic acid (FA). Batch experiments showed that Eu(III) adsorption on both micas was strongly dependent on pH but quite independent on ionic strength that is determined by Na+. Planar sites are available on both muscovite and phlogopite while interlayer sites only on phlogopite under Na+ and Ca2+ electrolytes (not for K+ and Cs+). An interlayer expansion of phlogopite, as indicated by a newly appeared diffraction peak at ~6° 2-theta, occurred along with Eu(III) adsorption, which was also confirmed by transmission electron microscopy. Furthermore, the initial Eu(III) concentrations, the concentration ratios between Eu(III) and Cs+, and the reaction sequences of Eu(III)-electrolytes-FA affected both the adsorption behaviour of Eu(III) and reversely the structural alteration of phlogopite. The sequential extraction showed that the adsorbed Eu(III) was mainly in the ion-exchangeable form while the addition of FA could increase the portion of coordinative species. The currently proposed Eu(III) adsorption mechanism can shed new light on predicting the migration of Ln/An(III) at the mica-rich solid-liquid interface on a molecular scale.
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Affiliation(s)
- Hanyu Wu
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Jie Chen
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Zengbo Su
- Fujian Fuqing Nuclear Power Co., Ltd., Fuqing, 350300, China
| | - Bin Ma
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Yizhe Ji
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Shuhan Lin
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Dingfang Xu
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Mingliang Kang
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China.
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Jiang TJ, Zhang XW, Xie C, Wu XY, Luo CW, Li M, Peng Y. Effective capture of aqueous uranium using a novel magnetic goethite: Properties and mechanism. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122236] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Fe3O4-modified sewage sludge biochar for U(VI) removal from aqueous solution: performance and mechanism. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07782-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Yao A, Xiong X, Kang M, Guo Y, Chen C, Chu T. Direct dissolution of UO 2 in carboxyl-functionalized ionic liquids in the presence or absence of Fe-containing ionic liquids. Dalton Trans 2020; 49:14881-14890. [PMID: 33074270 DOI: 10.1039/d0dt02740e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dissolution of UO2 is a prerequisite for the reprocessing of spent nuclear fuel. This study showed that UO2 could be directly dissolved in a single carboxyl-functionalized ionic liquid (IL), [HOOCMmim][Tf2N] 1-carboxymethyl-3-methylimidazolium bistriflimide, or [HOOCEtmim][Tf2N] 1-carboxyethyl-3-methylimidazolium bistriflimide. The addition of an extra Fe-containing IL, [Emim][FeCl4] (Emim, 1-ethyl-3-methylimidazolium) or [Bmim][FeCl4] (Bmim, 1-butyl-3-methylimidazolium) could significantly improve the dissolution kinetics. Results demonstrated that the dissolution process in the early stage could be described by using the pseudo first-order rate law. The apparent activation energy for UO2 dissolution in the mixture of the Fe-containing IL and carboxyl-functionalized IL was calculated to be ∼67 kJ mol-1, implying that the reaction was mainly controlled by a chemical process. Nevertheless, the influence of the diffusion process is non-negligible since the IL has a relatively high viscosity that can retard the diffusion of the formed uranyl species from the UO2 surface. Spectroscopic studies and density functional theory calculations indicated that the uranyl ion coordinated with carboxylate groups is the predominant product for UO2 dissolution in the single carboxyl-functionalized IL, while uranyl chloride complexes would also form in the mixed ILs. The dissolved uranyl species can be successfully recovered from the ILs by extraction. The success of UO2 dissolution in the carboxyl-functionalized IL with or without the Fe-containing IL indicates that the Fe-containing IL and oxygen can serve as an effective catalyst and oxidant for the dissolution of UO2, respectively.
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Affiliation(s)
- Aining Yao
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, 519082 Zhuhai, China.
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