Abstract:

Ionic liquids (ILs) have been widely used for CO₂ separation because of their unique properties, such as negligible vapor pressure, tunability for aimed application and high solubility for CO₂. However, the high viscosity and pricey cost of ILs limit their use in industrial applications. Thus, immobilization of ILs in membranes becomes one of the hot research spots in IL field due to the ILs based membranes possess both the advantages of ILs and membranes. This review summarizes the latest research on supported ionic liquid membranes, polymerized ionic liquid membranes and ionic liquid composite membranes for CO₂ separation. It is also discussed how the structures of ILs and ILs contents influence on the gas separation performances and stabilities of membranes. The research indicates that ILs composite membranes have high separation performance and stability, which is one of the prospective materials for CO₂ capture. The future research should highlight on the development of the novel fuctionalized ILs composite membranes and the trade-off of high CO₂ permeation rate and high stability to enhance the CO₂ separation performance. Besides, the study on the fabrication of composite membrane, gas transportation in membrane and CO₂ separation mechanism will inevitably attract considerable attentions.

Key words: ionic liquids, membranes, carbon dioxide, gas separation

摘要：

离子液体由于具有不易挥发、结构可调、对CO₂有良好的吸收性能等特点而成为当前CO₂分离领域的研究热点,但因高黏度和高成本问题而限制了其工业化应用。将离子液体与气体分离膜材料结合,得到的新型分离膜材料兼具离子液体和膜的优势,成为当前离子液体研究领域的趋势之一。针对这一热点问题,综述了离子液体支撑液膜、聚离子液体膜和离子液体共混/杂化膜在CO₂分离方面的研究现状和进展,讨论了离子液体结构和含量对膜分离性能、稳定性等的影响。相关研究表明,离子液体共混/杂化膜具有较高的分离性能和稳定性,是一种很有应用前景的CO₂分离材料。提出该领域的重点发展方向,即开发新的功能化离子液体共混/杂化膜材料是解决高渗透通量与高稳定性之间矛盾、强化CO₂分离性能的有效途径,深入研究离子液体共混/杂化膜的形成机制、气体在膜中的渗透行为以及CO₂分离机理。

关键词: 离子液体, 膜, 二氧化碳, 气体分离