Pursuit of efficient CO₂-capture membranes: graphene oxide- and MOF-integrated Ultrason^® membranes

Abstract: High-performance mixed-matrix membranes (MMMs) were developed to help control the global warming by capturing and sequestrating carbon dioxide (CO₂) from post combustion flue gas originating from burning of fossil fuels. MMMs of different compositions were prepared by synergistically doping glassy polymer Ultrason^® S 6010 (US) with nanosheets of graphene oxide (GO) and nanocrystals of zeolitic imidazolate frameworks (ZIF-300) in varying degrees. Solution-casting technique was used to fabricate various MMMs to optimize their CO₂ capturing performance from a CO₂-enriched gas mixture. The prepared composite membranes indicated enhanced filler–polymer interfacial adhesion, consistent distribution of nanofillers, and thermally stable matrix configuration. Owing to the synergistic effect of incorporated nanofillers, CO₂ permeability, and CO₂/N₂ permselectivity of the membranes were enhanced as demonstrated by gas sorption and permeation experiments. As compared to neat Ultrason^® membrane, CO₂ permeability and CO₂/N₂ ideal selectivity of fabricated MMMs doped with 30 wt% ZIF-300 nanocrystals and 1 wt% GO nanosheets were considerably improved. Key features of the fabricated MMMs include their structural and thermal stability coupled with improved gas separation performance. Graphical abstract: [Figure not available: see fulltext.].