Ionic liquid modified graphene oxide-PEBA mixed matrix membrane for pervaporation of butanol aqueous solutions

Abstract

This work explored a novel way to modify graphene oxide (GO) with ionic liquid (IL) and incorporate the modified GO into polyether block amide (PEBA) membrane for pervaporation of butanol aqueous solutions. The adsorption properties of GO and ionic liquid N-octylpyridiniunm bis (trifluoromethyl) sulfonyl imide [OPY][Tf2N] modified graphene oxide (IL-GO) for butanol and water were investigated via molecular simulation. Because ionic liquid [OPY][Tf2N] has good butanol affinity and hydrophobicity, the adsorption selectivity of butanol over water by the IL-modified GO increased by about 4 times compared with the pristine GO. Then IL-GO was incorporated into PEBA to fabricate mixed matrix membrane. The membrane was characterized, and the pervaporation performance of the membrane was evaluated. Pervaporation experiments showed that the incorporation of IL-GO is in favour of enhancing the membrane performance. Compared with pristine PEBA membrane, at 35 °C, for 2.5 wt% butanol aqueous solutions, the separation factor and permeation flux of the mixed matrix membrane with 1 wt% content of IL-GO were increased by 31.5% and 18.2%, respectively. Meanwhile, connecting ionic liquid to GO can effectively improve the membrane stability by preventing the loss of ionic liquid in the pervaporation process.