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

Poly(ionic liquid) (PIL)-based membranes for CO 2 removal attract increased interest due to the tunability of their chemical structure and processability of polymers. In this work, the IL cation of 1-vinylimidazole was selected as the polymeric backbone to connect the cyano- and carboxyl-based side chains to explore their effects. The synthesized PILs were blended with polyacrylamide (PAM) to prepare composite membranes by coating the mixed solutions on polysulfone (PSF) membranes. The CO 2 permeance and CO 2 /N 2 selectivity of these prepared PIL-based membranes were tested to evaluate their CO 2 separation performance. The results demonstrate that the cyano-based side chain showed better CO 2 separation performance compared to a carboxyl-based side chain of PILs. The best membrane performance for CO 2 permeance increased by 200% and CO 2 /N 2 selectivity increased by 195%. Here, the prepared PIL-based membranes provide a potential prospect for improving the CO 2 separation performance by adjusting the chemical structure of PILs. However, optimization related to cation, anion, and side chain groups should be conducted to break through the CO 2 /N 2 separation performance for industrial carbon capture.