Carbon capture via novel Cu(II)-DDA metal–organic frameworks-based hybrid membranes

An important contributor to global warming is the incessant escalation in carbon dioxide gas (CO₂) levels in the air, mainly attributed to combustion of fossil fuels. A promising strategy to regulate emission of greenhouse gases into open air is the implementation of carbon capture systems at existing and prospective carbon-releasing infrastructures. Being a distinguished class of mesoporous materials, metal–organic frameworks (MOFs) have great potential to efficiently alleviate CO₂ emissions into the atmosphere. Nanocrystals of a newly developed Cu(II)-DDA MOF were incorporated into polysulfone (PSF) matrix in varying concentrations to fabricate hybrid membranes to enhance their carbon capture efficiency. The prepared mixed-matrix membranes (MMMs) demonstrated better filler-matrix interfacial adhesion, homogenous nanofiller dispersal, semicrystalline domains and thermally resistant structure. Gas adsorption tests conducted on both the Cu(II)-DDA MOF nanocrystals and hybrid membranes indicated good adsorption capacity for CO₂ as compared to N₂. Experiments using cast MMMs revealed that doping the polymer matrix with MOF nanofillers increased the CO₂ permeability and the CO₂/N₂ selectivity of the cast MMMs. In comparison to the pure PSF membrane, the CO₂ permeability and CO₂/N₂ permselectivity of the composite membrane doped with 5 wt% Cu(II)-DDA MOF nanocrystals were nearly doubled.