Abstract:

In recent years， global carbon dioxide emissions have exceeded 37 billion tons per year， which has severely affected the climate and the natural environment. There is an urgent need to develop carbon capture， utilization and storage technologies. Gas membrane separation, as a kind of process without phase change, could be launched under mild condition and concise operation. This technique, along with the continuous upgrade in both selectivity and permeability for membrane materials, has been the major tendency for global carbon capture. In this work, poly(ionic liquids), honored to be the next-generation membrane materials, are introduced. These new emergent materials, generally abundant with CO₂-philic groups, are hopeful to achieve ultra-high selectivity for carbon capture. The design and synthesis of specific cationic poly(ionic liquids), including both main-chain and branched-chain types, were summarized from the viewpoint of solution-diffusion mechanism for gas permeation. The emphases in this review are the selection of cationic and anionic groups, the selection of synthesis routes, and the micro-structure design for membranes. Furthermore, the advantages and the challenges to utilize those functional poly(ionic liquids) as membrane materials for CO₂ separation are discussed.

Key words: membrane, ionic liquids, polymer, permeation, CO₂ capture, selectivity

摘要：

近年来，全球二氧化碳排放超过370亿吨/年，对气候和自然环境造成严重影响，亟需发展碳捕集、利用与封存技术。气体膜分离是一种条件温和、操作简单的无相变分离技术，随着高渗透性、高选择性膜材料的不断涌现，逐渐成为全球碳捕集技术的主要发展方向。聚离子液体膜材料中含有大量高度亲和二氧化碳的功能基团，有望实现超高渗透选择性，被誉为下一代气体分离膜材料。综述了聚离子液体膜材料的研究进展，以渗透机制为主线重点介绍了面向碳捕集的阳离子型聚离子液体膜材料(主链型和支链型)的设计合成，包括阳离子和阴离子基团的选择，合成途径的选择，以及聚离子液体膜的结构设计优化。讨论了聚离子液体作为二氧化碳分离膜材料的优势和面临的挑战。

关键词: 膜, 离子液体, 聚合物, 渗透, 二氧化碳捕集, 选择性