离子液体支撑液膜的CO_2/CH_4分离性能  

Supported ionic liquid membranes for CO_2/CH_4 separation

作　　者：伍艳辉[1] 张天豪[1] 段永超[1] 于世昆[1] 

机构地区：[1]同济大学化学系,上海200092

出　　处：《化工学报》2013年第S1期111-117,共7页CIESC Journal

基　　金：上海市自然科学基金项目(10ZR1432000);中央高校基本科研业务费专项资金项目~~

摘　　要：由于离子液体对CO2具有较好的溶解选择性,离子液体支撑液膜分离CO2越来越受到关注。比较了含3种不同阴离子的常规离子液体([bmim][BF4]、[bmim][PF6]、[bmim][Tf2N])作为支撑液膜的液膜相分离CO2/CH4的性能,考察了咪唑环上烷基链长对离子液体支撑液膜性能的影响。考虑向离子液体中引入胺基和羧基等亲CO2基团,制备了1-丁基-3-甲基咪唑丙氨酸离子液体([bmim][β-Ala]),考察了[bmim][β-Ala]支撑液膜分离CO2/CH4的性能,并对在CO2渗透测试前后的支撑液膜进行了FT-IR分析,发现氨基酸离子液体中的—NH2和CO2的较强作用以及该离子液体的高黏性影响了CO2的透过性,使[Bmim][β-Ala]支撑液膜的CO2透过率低。Ionic liquid have shown preferential solubility for CO2,more and more attentions have been paid to CO2 separation with supported ionic liquid membranes(SILMs).In this paper,three conventional imidazolium-based ionic liquids containing different anions,[bmim][BF4 ],[bmim][PF6 ]and[bmim][Tf2 N], were used as membrane liquids for CO2 /CH4 separation.The performances of these SILMs were studied and discussed.The supported liquid membrane with[bmim][Tf2 N]showed the highest permeability of CO2 for this ionic liquid has the best solubility to CO2and rather low viscosity.And the effect of the alkyl chain length of imidazole ring on the performance of SILMs was also investigated.With the increase of alkyl chain length,the CO2 permeability and ideal selectivity of CO2/CH4 decrease.A new task-specific ionic liquids(TSIL)which has two CO2-philic groups,amino and carboxyl group([bmim][β-Ala]) was synthesized and the corresponding ionic liquid supported membrane was made.FT-IR spectra of [bmim][β-Ala]-PVDF before and after CO2 permeation test showed that the chemical reaction occurred between NH2 and CO2,generating a new carboxyl groups,which made CO2 difficult to desorb on the downstream side of SILMs.Therefore the SILMs with[bmim][β-Ala]showed very low CO2permeability.

关 键 词：离子液体 支撑液膜 CO2 

分 类 号：TQ028.8[化学工程]