Amino-ionic liquids assisted highly compatible mixed matrix membrane of ZIF-8 and PIM-1 for efficient CO2/N2 separation

Abstract

Mixed matrix membranes (MMMs), which incorporate metal-organic frameworks (MOFs) nanofillers within a polymer matrix, offer a highly promising solution for CO2 capture and separation. However, poor interfacial compatibility and filler aggregation in MMMs pose significant challenges to enhancing CO2/N2 separation performance. Here, we present a novel approach using amino ionic liquid modification to optimize MMMs, where the modified AFIL promotes the formation of ZIF-8 with well-defined facets and sharp edges, and enhances the compatibility between ZIF-8 particles and PIM-1 polymer matrix for favorable CO2 affinity and selective CO2 transport. The resulting 10 wt.% AFIL@ZIF-8/PIM-1 exhibits exceptional gas separation performance with a CO2 permeability of 7864262.2 Barrer and a CO2/N2 selectivity of 29.661.96. More importantly, the incorporation of AFIL into the ZIF-8 pores significantly enhances the thermal stability and aging resistance of AFIL@ZIF-8/PIM-1 MMMs via structural support and hydrogen bonding interactions. This work provides a practical approach to developing hybrid membranes for CO2/N2 separation, showcasing improved overall performance and strong interfacial compatibility.