功能化离子液体膜材料设计及分离CO2的调控机制

Developing lower energy consumption CO2 capture process is one of the feasible routes to resolve the global warming problem. In recent years, capturing CO2 with ionic liquids (ILs) is believed as one of the effective methods, but the higher viscosity and costs of ILs limit to a great extent their industrial applications. Therefore, in order to solve the problems, IL membrane technology has been developed due to great potential as an energy-efficient and environment-friendly CO2 separation option. In view of low stability of supported ionic liquid membranes (SILMs) and low separation performances of polymerized ionic liquid membranes (PILMs), functionalized IL-polymer mixed membranes are proposed to realize both high CO2 separation performances and good stablity. By a combination of simulation caculations and experimental methods, a series of novel functionalized pyridinium-based ILs with excellent absorption performances, high thermal stability, lower cost and toxicity, higher biodegradability will be designed and synthesized to prepare the IL-polymer mixed membranes. The influence of structure of ILs, cluster, hydrogen bond and the content of ILs on the microstructures and properties of membranes will be systematically investigated, and the relationship between the structures of ILs and separation performances of mixed membranes will be obtained. Furthermore, the effect of the preparation conditions such as the content of polymers, the solvents and solvent evaporation termperature will be also studied. The mechanisms of structure regulation on separation permeability, selectivity and stability of mixed membranes and the interaction between gas molecules (such as CO2, CH4 and N2) and membranes will be given. This project will provide theoretical and technical basis for the design of IL-polymer mixed membranes with high performances and their industrial applications for CO2 separation.

开发低能耗CO2捕集技术是当前解决温室效应的重要途径。针对目前离子液体支撑液膜稳定性差和聚离子液体膜分离性能较低等难题，本项目基于离子液体良好的CO2分离性能和结构可调等优势，提出功能化离子液体调控共混膜材料结构和性能的新思路。采用实验表征与模拟计算结合的方法，设计合成具有特殊功能基团、物化性质稳定、环境友好的新型吡啶类离子液体，进一步制备出离子液体-聚合物共混膜，实现CO2高效和低能耗分离。重点研究离子液体阴阳离子结构、功能基团、相互作用及离子液体含量对共混膜的微观结构和性能的影响，获得离子液体结构与膜分离性能的内在关系；研究离子液体-聚合物相容性、制膜温度和溶剂等对膜制备过程及膜结构性能的影响，获得共混膜结构对分离渗透性、选择性及稳定性的调控机制和气体渗透分离机理。本研究将为高渗透性、高选择性和高稳定性离子液体共混膜材料的设计及分离气体技术的工业化应用提供重要的理论基础。

本项目针对当前离子液体支撑液膜稳定性差和聚离子液体膜分离性能较低等难题，围绕功能离子液体设计及构效关系、离子液体膜材料设计制备表征、离子液体膜分离CO2性能及机理开展相关研究，从而达到获得高性能离子液体膜材料设计及高选择性分离CO2的共性科学基础，为形成具有工业应用价值的新一代碳捕集技术提供科学依据。项目严格按执行任务书的研究计划进行，如期完成了所有研究内容，达到了预期目标和指标，取得的进展包括：采用COSMO-RS方法计算获得了12种常见气体（CO2、NH3、SO2、H2S、C2H2、COS、C2H4、CO、H2、N2、O2和CH4）在13585种离子液体的亨利系数，建立了较为全面的离子液体对气体的亨利系数数据库；在此基础上，在阳离子上引入不同的醚基基团，设计合成了粘度较低、稳定性良好的醚基吡啶功能离子液体，且能显著提高对CO2/CH4选择性；进一步采用合成的醚基功能离子液体和醋酸纤维素物理共混，制备了系列稳定性好的离子液体共混膜材料，获得了阴阳离子结构、离子液体含量等对CO2渗透性和选择性的影响规律，并对其机理进行了分析，为高性能离子液体膜材料的设计提供了理论指导。.项目执行期间，在Green Chem., AIChE J. Ind. Eng. Chem. Res., RSC Adv.等期刊发表学术论文15篇，申请/授权专利11项，参编英文书章节2章，参加国际/国内学术会议并作主题/邀请/口头报告5次。项目负责人2016年获得中科院过程所工学博士学位，并晋升为副研究员，入选2017年“中科院过程所青年创新促进会”和2018年“中科院青年创新促进会”。项目组1名成员晋升为副研究员，培养博士/硕士生共4名。