选取咪唑型离子液体修饰金属有机框架填料ZnBDC制备IL@ZnBDC纳米复合填料,通过物理共混的方式将其引入PI中制备PI-IL@ZnBDC混合基质膜。结果表明,复合填料的引入改善了填料与PI间的相容性,增加了混合基质膜的分子链间距,强化了膜内CO₂扩散过程。同时,离子液体中含有与CO₂有较强亲和作用的三氟甲基、磺酸基团和咪唑基团,促进了CO₂在膜内的溶解,进而协同强化了PI-IL@ZnBDC混合基质膜的溶解-扩散机制,提升了CO₂气体通量和选择性。相较于纯PI膜,PI-IL@ZnBDC-2膜表现出优异的气体分离性能,CO₂的渗透系数为10.97 Barrer,CO₂/CH₄的选择性为42.21,分别较纯膜提升了59.9%和41.5%。

An imidazole ionic liquid (IL) is selected to modify ZnBDC,a metal organic framework filler,to prepare IL@ZnBDC nanocomposite filler that is added into polyimide (PI) through physical blending route to prepare PI-IL@ZnBDC mixed matrix membrane.It is found that the addition of nanocomposite filler improves the compatibility between filler and PI,and increases the molecular chain spacing of the mixed matrix membrane,therefore enhancing the CO₂ diffusion process in the membrane.Meanwhile,the trifluoromethyl group,sulfonic acid group and imidazole group contained in the IL have strong affinity with CO₂,which promotes the dissolution of CO₂ in the membrane,further synergistically enhances the dissolution-diffusion mechanism of PI-IL@ZnBDC mixed matrix membrane,and simultaneously improves the CO₂ permeability and the selectivity of CO₂/CH₄.Compared with pure PI membrane,PI-IL@ZnBDC-2 membrane shows excellent gas separation performance,with a CO₂ permeability of 10.97 Barrer,and a CO₂/CH₄ selectivity of 42.21,which are 59.9% and 41.5% respectively higher than those by pure membrane.

刘向东(1985-),男,硕士,高级工程师,研究方向为海上平台油气处理工艺,通讯联系人,liuxd6@cnooc.com.cn。