Selective\nGas Permeation in Mixed Matrix Membranes\nAccelerated by Hollow Ionic Covalent Organic Polymers

Abstract

Mixed\nmatrix membranes (MMMs) have gained great attention for the\nefficient CO₂ removal from raw nature gas or biogas (CO₂/CH₄ separation) and flue gas (CO₂/N₂ separation). Nevertheless, the development of high-performance\nMMMs for industrial applications is largely limited by the lack of\nsuitable porous fillers. Herein, a novel ionic covalent organic polymer\n(ICOP-1) consisting of gas selective pores and hollow cavities is\nfacilely fabricated using a metal triflate catalyzed condensation\nreaction. Considering its unique structural properties, ICOP-1 is\nexplored as a novel filler to enhance the gas separation properties\nof polysulfone (PSf) membranes. Defect-free MMMs are successfully\nprepared owing to the high polymer–filler affinity originating\nfrom the organic nature of these two phases. Besides, the large cavities\nand size-selective pores of ICOP-1 lead to a simultaneous increase\nin membrane CO₂ permeability and CO₂/CH₄, CO₂/N₂ selectivities. With the addition\nof only 0.5 wt % of ICOP-1 fillers, the as-prepared MMM demonstrates\nthe optimal gas separation performance with a CO₂/CH₄ selectivity of 39.7 (at a CO₂ permeability of\n6.19 Barrer) and a CO₂/N₂ selectivity of 36.7\n(at a CO₂ permeability of 6.85 Barrer), opening new opportunities\nin membrane-based industrial CO₂ capture applications.