High‐Performance Polymers for Membrane CO₂/N₂ Separation

Abstract

This Concept examines strategies to design advanced polymers with high CO permeability and high CO /N selectivity, which are the key to the success of membrane technology for CO capture from fossil fuel-fired power plants. Specifically, polymers with enhanced CO solubility and thus CO /N selectivity are designed by incorporating CO -philic groups in polymers such as poly(ethylene oxide)-containing polymers and poly(ionic liquids); polymers with enhanced CO diffusivity and thus CO permeability are designed with contorted rigid polymer chains to obtain high free volume, such as polymers with intrinsic microporosity and thermally rearranged polymers. The underlying rationales for materials design are discussed and polymers with promising CO /N separation properties for CO capture from flue gas are highlighted.

Design, synthesis, and gas permeation properties of polyimides containing pendent imidazolium groups

“…Owing to their excellent thermal and mechanical stability, structural tunability, and film‐forming ability, polymeric membranes have attracted considerable attention for various applications such as hydrogen recovery, O 2 enrichment, purification of natural gas, and so forth . The performance of membranes for gas separation applications is judged by permeability and selectivity .…”

“…It has been demonstrated that polymers containing ionic groups exhibit excellent gas permeation properties and their gas permeation properties can be tuned by varying compositions of ionic groups . For CO 2 separation, polymers containing ionic groups showed high selectivity and high permeability because of interaction of ionic counterpart with CO 2 . To date, various examples of polymers containing ionic groups have been reported for gas separation applications including polybenzimidazoles, polyethers, polyimides, and so forth .…”

Ionic Liquids‐Based Membranes for Carbon Dioxide Separation

“…found that the substituent of PILs membrane as well as anion play important roles in governing gas diffusion and sorption, and thus the overall permeability. Liu et al . prepared the membranes with CO 2 ‐philic groups (poly(ethylene oxide)‐containing polymers and PILs) for CO 2 /N 2 Separation.…”

Effects of tertiary amines and quaternary ammonium halides in polysulfone on membrane gas separation properties

“…Polymeric membranes are of great interests for removal of CO 2 from a mixture of light gases, such as CH 4 and N 2 , due to their inherently high‐energy efficiency in gas separation . For example, membrane technology is industrially practiced to remove CO 2 from natural gas (containing mainly CH 4 ) to avoid the corrosion of pipelines and has been extensively explored for CO 2 capture from post‐combustion flue gas derived from fossil fuels (containing mainly N 2 ) . These polymers selectively permeate CO 2 and reject CH 4 and N 2 based on the solution‐diffusion mechanism in which gas permeability ( P A ) of gas A is: where, S A is the solubility coefficient and D A is the diffusion coefficient.…”