文献类型：期刊文献

英文题名：Balancing dissolution and diffusion for enhanced CO2/CH4 separation in polyimide membranes via ion solvation

作者：Chen, Yuhan[1,2];Liu, Xiang[1,2];Wang, Xuan[1,2];Zhang, Peibing[3];Gao, Qingwei[4];Xu, Xiaofei[1,2];Cui, Jing[3];Zhao, Shuangliang[5]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China;[3]SINOPEC Shanghai Res Inst Petrochem Technol Co Ltd, Shanghai 201208, Peoples R China;[4]Shanghai Univ Elect Power, Coll Environm & Chem Engn, Shanghai Key Lab Mat Protect & Adv Mat Elect Power, Shanghai 201306, Peoples R China;[5]Guangxi Univ, Coll Chem & Chem Engn, Guangxi Low Carbon Technol & Green Chem Mat Lab, Nanning 530004, Peoples R China

年份：2026

卷号：325

外文期刊名：CHEMICAL ENGINEERING SCIENCE

收录：;EI(收录号：20260519996202);WOS:【SCI-EXPANDED(收录号:WOS:001678751300001)】；

基金：The authors acknowledge the financial support from the National Natural Science Foundation of China (No. 22508114 and 22578263) , and the Guangxi Science and Technology Major Program (No. AA23073019) , and the Science and Technology Commission of Shanghai Municipality (No. 25DZ3002701) .

语种：英文

外文关键词：Polyimide membranes; Ionic liquids; CO 2 /CH 4 separation; Dissolution-diffusion balance; Ionsolvation

摘要：Understanding CO2/CH4 separation in polyimide (PI) membranes at the molecular scale is essential for guiding the design of advanced gas separation materials. In this work, all-atom simulations are employed to study the gas transport in two 6FDA-based PIs and one non-fluorinated PI. The role of ion solvation in the separation is explored in a composite membrane of PI and ionic liquids (ILs). The results show that CO2 separation arises from the coupled contributions of dissolution and diffusion. Owing to the quadrupolar interactions, CO2 exhibits preferential adsorption at functional sites in PI chains, including carbonyl oxygen, imide nitrogen, and adjacent methyl carbon atoms. Incorporation of ILs reorganizes the local microstructure by weakening CO2 and PI interactions through competitive ion-gas binding, while the steric presence of ions simultaneously limits the available diffusion pathways. For the cases studied, the CO2/CH4 selectivity in IL-PI composite membranes reaches 67.02, approximately 2.9 times greater than that of pristine PI membrane. Notably, for the systems studied here, solubility selectivity contributes slightly more than diffusivity selectivity (the contribution ratio is approximately at 6:4) in the best separation cases. The results reveal that the separation mechanism is governed by delicate balance between dissolution and diffusion, which can be tuned by the presence of ionic liquids.