Abstract:

Ionic liquids (ILs), comprised entirely of cations and anions, are classified as property-tunable and green solvents. Due to their special properties, such as high thermal stability, low volatility, as well as outstanding physical and chemical nature, ILs have shown great application prospects in many fields and become a research hotspot in recent years. However, the inevitable loss during the use of ILs and the problem of relatively high cost, the recycling and reuse of ILs have drawn great attentions with the scaling up of the ionic liquid-based technologies. Before the large-scale industrial application of ILs, the problem of IL recycling must be solved. This review aims to introduce methods of recycling ionic liquids, which have been investigated widely in recent years. We mainly discussed five methods applied in recycling and reuse of ILs, i.e. distillation, extraction, membrane separation, adsorption and phase separation. The advantages and disadvantages were summarized and analyzed. The results indicated that the recycling and reuse of ILs will greatly enlarge the application range of ILs, while there are still some other challenges need to be resolved. For example, the recycling scale is yet small and the methods reported in the literature are still in their infancy stage. Finally, the review puts forward the future research direction for recycling and reuse of ILs.

Key words: ionic liquids, recycle, reuse, green technology

摘要：

离子液体是完全由阴阳离子组成的绿色可设计溶剂。因为其稳定性好、极低挥发性及独特的物理化学性质，使其在诸多领域具有巨大的应用潜力，近年来已成为研究热点。由于离子液体相对昂贵的生产成本，随着应用规模及范围的逐渐扩大，如何高效回收循环利用离子液体受到极大关注，成为离子液体产业化必须要解决的难题之一。本文概述了近年来在离子液体回收应用方面的研究进展，重点探讨了利用蒸馏、萃取、膜分离、吸附分离以及相分离等方法回收离子液体存在的优势及不足。分析表明，离子液体的回收和循环利用将极大促进离子液体产业的发展，但目前的规模仍然偏小且多处于研发阶段，在此基础了提出了未来拟重点开发的回收利用技术及发展趋势。

关键词: 离子液体, 回收, 循环利用, 绿色技术