Title: 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

Biography:

Wu H will complete his doctoral course in September, 2019, in the department of nuclear engineering from 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.

Abstract

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 SF_Lu/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.