Author(s)

Chan Jin¹, Jiangtao Hu¹, Jianqiang Wang¹, Chunyun Xie¹, Yajun Tong², Linjuan Zhang¹, Jing Zhou¹, Xiaojing Guo¹, Guozhong Wu^1*

¹Center for Thorium Molten Salt Reactor System, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.
²Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.

High efficient removal and recovery of uranium and thorium from nuclear waste solution are essential for environmental preservation and fuel recycle. A new polymer fiber adsorbent (UHMEPE-g-PAO fiber), prepared by amidoximation of grafted polyacrylonitrile onto Ultra High Molecular Weight Polyethylene (UHMWPE) fiber, was used to remove the uranyl and thorium ions from acid aqueous solutions and its performance was carefully investigated. It was found that uranyl ion can penetrate the fiber through the connected pore structures, forming (UO₂) (R-C(NH₂)-NO)₂ chelates with the amidoxime groups within the fiber. Two amidoxime groups (U-N and U-O_eq) and two water molecules (U-O_eq2) are bound to uranyl ion in the fiber. On the contrary, thorium ions are adsorbed mainly on the fiber surface in the form of Th(OH)₄ precipitate that blocks the entrance of Th⁴⁺ ion into fiber pores. The maximum included other two capacities of uranyl and thorium ions were estimated to be 262.01 mg/g and 160 mg/g at room temperature with pH 3.0, respectively. The results also indicate that the UHMWPE-g-PAO fiber has higher adsorption selectivity for uranyl ion than thorium ion. Uranium and thorium oxide particles were obtained as the ultimate product after sintering of the fiber adsorbent. This novel and environmentally friendly adsorption process is feasible to extract uranium or thorium from acidic aqueous solution.

UHMWPE Fiber, Uranium Ions, Thorium Ions, Selective Absorption Mechanism, XAFS, SR-FTIR

Jin, C. , Hu, J. , Wang, J. , Xie, C. , Tong, Y. , Zhang, L. , Zhou, J. , Guo, X. and Wu, G. (2017) An Amidoximated-UHMEPE Fiber for Selective and High Efficient Removal of Uranyl and Thorium from Acid Aqueous Solution. Advances in Chemical Engineering and Science, 7, 45-59. doi: 10.4236/aces.2017.71005.