Mutual separation of trivalent lanthanides in nitric acid solution by a novel hydrophobic ionic liquid including N,N,N’,N’-tetrakis(2-pyridylmethyl)-1,3-diaminopropane-2-amido structure: A soft N and hard O donor combined strategy

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Wu H, Zhang XX, Yin XB, Nakase M, Inaba Y, Harigai M, Kobayashi T, Yaita T and Takeshita K

Tokyo Institute of Technology, Japan
China Atomic Energy Authority, China
Japan Atomic Energy Agency, Japan

: J Chem Appl Chem Eng

Abstract

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A novel hydrophobic ionic liquid including N,N,N’,N’- tetrakis(2-pyridylmethyl)-1,3-diaminopropane-2- amido structure ((IL-TPEN)+NTf2-) was successfully synthesized. Its extraction performance of Eu3+ from nitric acid solution was investigated by dissolving in a low viscosity ionic liquid (C6mim)+NTf2-. As a result, it was found that extraction kinetic was fairly fast and can reach equilibrium within 1 h. The extraction percentage of Eu3+ varied with the pH value. The stripping of extracted metals from (C6mim)+NTf2- into a receiving phase was successfully achieved under 1.0 M nitric acid condition without adding any other metal complex forming agents. Slope analysis confirmed that (IL-TPEN)+NTf2- formed 1:3 complex with Eu3+ in (C6mim)+NTf2- system. On the other hand, (IL-TPEN)+NTf2- showed better preference to heavier lanthanides than lighter ones, and the maximum SFLu/ La= 33.1. Furthermore, the coordination environment between Eu3+ and (IL-TPEN)+NTf2- was also studied by means of FT-IR, 1H-NMR, EXAFS etc. The results indicated both soft N donor (pyridine group) and hard O donor (amido group) participated in the formation of Eu3+ complex. Therefore, the soft-hard donor combined (IL-TPEN)+NTf2- can be feasibly utilized in the mutual separation of lanthanides.

Biography

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Wu H is pursuing his PhD in the department of nuclear engineering at Tokyo Institute of Technology, Japan. Currently, his research work mainly focuses on the mutual separation of rare earth metals by using ionic liquids, and this research is financed by Japan Society for the Promotion of Science (JSPS-DC2). He has published several papers in reputed journals such as Dalton Trans., Chem Lett. etc.

E-mail: wu.h.ac@m.titech.ac.jp