Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan.
Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, 274-8510, Japan.
Anal Sci. 2021 Jan 10;37(1):119-130. doi: 10.2116/analsci.20SAR11. Epub 2020 Oct 23.
This review summarizes recent progress in solvent extraction of rare earth elements (REEs) using an ionic liquid (IL) as the extraction solvent. These IL extraction systems are advantageous owing to the affinity of ILs for both charged and neutral hydrophobic species, in contrast to conventional organic solvent extraction systems. Herein, REE extraction studies using ILs are detailed and classified based on the type of extraction system, namely extraction using anionic ligands, extraction using neutral ligands, synergistic extraction, extraction without extractants, and a specific system using task-specific ionic liquids (TSILs). In IL extraction systems, the extracted complexes are often different from those in organic solvent systems, and the REE extraction and separation efficiencies are often significantly enhanced. Synergistic IL extraction is an effective approach to improving the extractability and separability of REEs. The development of novel TSILs suitable for IL extraction systems is also effective for REE separation.
本文综述了近年来使用离子液体（IL）作为萃取溶剂萃取稀土元素（REEs）的最新进展。与传统有机溶剂萃取体系相比，这些 IL 萃取体系具有 IL 对带电和中性疏水性物质的亲和力的优势。本文详细介绍了基于萃取体系类型的 REE 萃取研究，即阴离子配体萃取、中性配体萃取、协同萃取、无萃取剂萃取和特定的功能化离子液体（TSILs）萃取。在 IL 萃取体系中，所萃取的配合物通常与有机溶剂体系中的不同，REE 的萃取和分离效率通常显著提高。协同 IL 萃取是提高 REE 萃取和分离效率的有效方法。开发适合 IL 萃取体系的新型 TSILs 也对 REE 分离有效。
