Improvement on the Radiation Stability of Multi-scale Supramolecular Assembly in Ionic Liquid-Based Extraction.

Abstract

The multi-scale supramolecular assembly (MSSA)-based extraction strategy with hydroxyl-functionalized ionic liquid (IL) is promising in the separation of metal ions from radioactive environments for which a comprehensive understanding toward the radiation stability of the MSSA system is necessary. Herein, we report on the analyses of the radiation stability of MSSA in extraction, especially the adopted ILs 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (IL-1) and 1-(2-hydroxyethyl)-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide (IL-2), by UV-vis, 1H NMR, and ESI-HRMS. It was found that the macroscopic assembly (MA) sphere could not be formed after γ irradiation on the extraction system with IL-1. On the contrary, the trisubstituted IL-2 instead of the disubstituted IL-1 remarkably improved the radiation stability of the MSSA system to guarantee the formation of the MA sphere. The high extraction efficiency could be kept, and the mechanism of such an improvement was revealed.