Interfacial sealing and functionalization of polysulfone/SAPO-34 mixed matrix membrane using acetate-based ionic liquid in post-impregnation for CO2 capture

Abstract

Abstract The CO2 selective ionic liquids (ILs) have been extensively studied in recent years, but their applications are limited by the high viscosity and cost. In this work, acetate-based ionic liquid was used to enhance and functionalize the interface between polysulfone (PSf) and SAPO-34 zeolite in the asymmetric mixed matrix membrane (MMM) prepared via phase inversion. The MMMs were post-modified by immersing the membranes into carboxylate IL solution (1-butyl-3-methylimidazolium acetate). The effects of IL concentration on the membrane morphology and separation performance in CO2 separation were studied. Fourier transform infrared spectra and energy-dispersive X-ray spectra showed that the IL was successfully incorporated into MMM. The post-impregnation of the membrane with IL improved the interface contact between the polymer and zeolite. The interfacial sealing using IL further enhanced the CO2/N2 selectivity of IL-modified MMM, about 818% higher than the CO2/N2 selectivity of unmodified MMM. The maximum selectivity of 39.60 was achieved using PSf membrane incorporated with 5 wt% of SAPO zeolite loading and modified with 0.4 M of IL. This membrane also sustained its separation performance even wet gas was fed.