CO2-Philic Imidazolium-Based Poly(Ionic Liquid) Composite Membranes for Enhanced CO2/N2 Separation

Poly-(ionic liquid) (PIL)-based membranes for CO2 removalattract increased interest due to the tunability of their chemicalstructure and processability of polymers. In this work, the IL cationof 1-vinylimidazole was selected as the polymeric backbone to connectthe cyano- and carboxyl-based side chains to explore their effects.The synthesized PILs were blended with polyacrylamide (PAM) to preparecomposite membranes by coating the mixed solutions on polysulfone(PSF) membranes. The CO2 permeance and CO2/N-2 selectivity of these prepared PIL-based membranes were testedto evaluate their CO2 separation performance. The resultsdemonstrate that the cyano-based side chain showed better CO2 separation performance compared to a carboxyl-based side chain ofPILs. The best membrane performance for CO2 permeance increasedby 200% and CO2/N-2 selectivity increased by195%. Here, the prepared PIL-based membranes provide a potential prospectfor improving the CO2 separation performance by adjustingthe chemical structure of PILs. However, optimization related to cation,anion, and side chain groups should be conducted to break throughthe CO2/N-2 separation performance for industrialcarbon capture.