离子液体萃取金属离子的研究进展

Advances in Metal Ion Extraction with Ionic Liquids

离子液体在金属离子萃取分离方向的研究是目前热点之一。通过阅读大量文献并总结各试验结果,可以让读者熟悉该领域研究的进展与困境,并为后续研究者提出新假设与研究理念提供了依据。离子液体作为一种新兴的绿色溶剂,在金属离子萃取分离方面,它较传统的有机溶剂表现出显著优势。本文概述了离子液体的组成、分类及特性,系统地总结了使用咪唑类、吡啶、吡咯类和四烷基铵、四烷基膦类离子液体萃取各类金属离子的研究进展,比较了它们取得的萃取、反萃取效果的异同。总结发现,该领域中,对咪唑类离子液体的研究最为普遍,且对金属离子的萃取表现出较理想的效果。其中含有羧基、硫脲基、氨基、硫醇等官能团的咪唑类离子液体对一些二价、三价金属离子及碱金属的萃取率均达90%以上;在普通烷基咪唑类离子液体中,加入某种螯合剂,也能对一些金属离子的萃取及反萃取达到理想效果,但相对一些功能化离子液体来说,操作较复杂。吡啶、吡咯类离子液体在金属萃取方面的应用相对较少,但也有学者进行研究,通过使用特定螯合剂与其结合,也会有一定的效果。四烷基铵、四烷基膦类离子液体大多将其溶在煤油或甲苯中,来研究对金属离子的萃取,得到较好效果。同时,功能化铵盐与膦盐对三价金属离子萃取的研究也逐渐增多。最后对离子液体在萃取领域的未来发展方向进行展望。

The research of ionic liquids in the direction of metal ion extraction and separation is one of the hotspots at present.By reading a large number of documents and summarizing the results of the experiment, readers can familiarize themselves with the progress and difficulties of the research in this field, and provide a basis for the follow-up researchers to put forward new hypotheses and research ideas. Ionic liquids, as a new green solvent, show significant advantages over traditional organic solvents in the extraction and separation of metal ions. This review summarized the composition, classification and properties of ionic liquids. In addition, the research developments and progress of extraction of various metal ions using imidazolium, pyridinium,pyrrolidinium, quaternary phosphonium and quaternary ammonium were systematically summarized, and the similarities and differences between their extraction and stripping effects were compared. It is shown that the study of imidazolium ionic liquids was the most popular in the field of metal ion extraction, and has an ideal effect on the extraction of metal ions. The imidazolium ionic liquids containing carboxyl group, thiourea group, amino group, mercaptan and other functional groups have more than 90% extraction rates of some two valence, trivalent metal ions and alkali metals. In the ordinary alkyl imidazolium ionic liquids, the addition of some chelating agent could also achieve the ideal effect on the extraction and reverse extraction of some metal ions, but the operation was more complicated than some functional ionic liquids. The application of pyridinium and pyrrolidinium ionic liquids in metal extraction was relatively small, but some scholars have also studied it by using specific chelating agents, which shows a certain effect. Quaternary phosphonium and quaternary ammonium ionic liquids were mostly dissolved in kerosene or toluene to study the extraction of metal ions and get good results. At the same time, the research on the extraction of trivalent metal ions by functionalized ammonium salts and phosphonium salts was also increasing. Finally, the future development direction of ionic liquids in the field of extraction was prospected.