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Ren Y, Bao H, Wu Q, Wang H, Gai T, Shao L, Wang S, Tang H, Li Y, Wang X. The physical chemistry of uranium (VI) immobilization on manganese oxides. JOURNAL OF HAZARDOUS MATERIALS 2020; 391:122207. [PMID: 32036313 DOI: 10.1016/j.jhazmat.2020.122207] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/09/2020] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
Manganese oxides show strong affinity towards uranium, and have a promising application in uranium immobilization in environmental protection. We successfully synthesized a series of Mn oxide materials of different structures and investigated their U(VI) immobilization performances. The results showed that all Mn oxides share similar sorption capacities per unit surface area, implying similar physical chemistry during immobilization. Among these Mn oxides, α-MnO2 shows the most outstanding performance for uranium uptake (280 mg/g). More detailed studies on interfacial properties of U(VI) on α-MnO2 were performed to elucidate the binding mechanism. The uptake was largely influenced by acidity, but less impacted by ionic strength, indicative of an inner-sphere binding mode. The selectivity for uranium is much higher than other selected metal ions, i.e. Co2+, Ni2+, Eu3+, etc. ATR-FTIR, and EXAFS results showed that in both mild acidic and neutral conditions, U(VI) formed bidentate binuclear structure on α-MnO2, as evidenced by υas(O = U=O) at 912 cm-1 and the number of Mn in U coordination shell. UO2(OH)2 precipitate was found at the molecular level in neutral condition (pH 7-8). The results reveal the physical chemistry in uranium immobilization process on manganese oxide surfaces and helps to better understand the uranium environmental migration. Furthermore, it provides an alternative approach for radioactive water purification.
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Affiliation(s)
- Yiming Ren
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China.
| | - Hongliang Bao
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 JiaLuo Road, Shanghai 201800, China
| | - Qian Wu
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Huaisheng Wang
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Tao Gai
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Lang Shao
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Shaofei Wang
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Hao Tang
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China
| | - Yingru Li
- Institute of Materials, China Academy of Engineering Physics, PO Box 9071-11, Mianyang, China.
| | - Xiangke Wang
- School of Environment and Chemical Engineering, North China Electric Power University, Beijing, China.
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