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

Abstract

Poly(ionic liquid) (PIL)-based membranes for CO2 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 CO2 permeance and CO2/N2 selectivity of these prepared PIL-based membranes were tested to evaluate their CO2 separation performance. The results demonstrate that the cyano-based side chain showed better CO2 separation performance compared to a carboxyl-based side chain of PILs. The best membrane performance for CO2 permeance increased by 200% and CO2/N2 selectivity increased by 195%. Here, the prepared PIL-based membranes provide a potential prospect for improving the CO2 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 CO2/N2 separation performance for industrial carbon capture.

Molecular Engineering of Copoly(ionic liquids)-Based Membranes for CO2 Separation

“…As depicted in the above results for gas separation performances (see Figure ), the membranes of M1-M4 and also the EtOH-pretreated membranes exhibit better performances than membranes of M5-M8, thereby these membranes with higher separation performance were selected for comparison with other PIL-based membranes reported in the literature . It can be found that the membranes developed in this work are closer to the “Robeson upper bound”.…”

“…Moreover, the surface and cross-sectional morphologies of the representative composite membranes of M1 and M5 were observed by SEM as shown in Figure B–E. For reference, the SEM images for the pristine PSF membranes were reported in our previous work . The PSF support exhibits a porous structure on the top layer and comb-shaped microporous channels on the middle part of the cross-sectional morphology.…”

“…The synthesis route of IL monomers (IL1:1-cyanomethyl-3-vinylimidazolium bromide and IL2:1-carboxymethyl-3-vinylimidazolium bromide) was the same as that reported in the literature and the specific synthesis steps are shown in Supporting Information Note 1. Following a similar procedure as reported in the literature, different molar ratios of IL1 monomers to AM (1:1 and 1:3) were applied for copolymerization.…”

Impact of Humidity on the CO2/N2 Separation Performance of Pebax-MOF Mixed Matrix Membranes

“…wet dry dry (4) where W wet and W dry represent the weight of the membrane at the water uptake equilibrium state and when completely dry, respectively.…”

“…CO 2 is a prevalent greenhouse gas, and its environmental impact has become increasingly critical due to economic and industrial development. , Carbon capture, utilization, and storage (CCUS) is a vital technology for mitigating global climate change. , It is noteworthy that in 2022, the CO 2 emissions from the power industry accounted for 39.3% of the total CO 2 emissions . A significant portion of these emissions arises from fossil fuel combustion in coal-fired power plants.…”