(650a) Efficient CO2 Capture By Functionalized Graphene Oxide Nanosheets As Fillers to Fabricate Multi-Permselective Mixed Matrix Membranes

A novel multi-permselective mixed matrix membrane (MP-MMM) is developed by incorporating versatile fillers functionalized with ethylene oxide (EO) groups and amine carrier into polymer matrix. The as-prepared MP-MMMs can separate CO₂ efficiently owing to the simultaneous enhancement of diffusivity selectivity, solubility selectivity and reactivity selectivity. To be specific, MP-MMMs were fabricated by incorporating polyethylene glycol- and polyethylenimine-functionalized graphene oxide nanosheets (PEG-PEI-GO) into commercial low-cost Pebax^® matrix. The PEG-PEI-GO plays multiple roles in elevating the membrane performances. Firstly, the high aspect ratio GO nanosheets in polymer matrix increase the tortuous path of gas diffusion and generate a rigidified interface between polymer matrix and fillers, enhancing the diffusivity selectivity. Secondly, PEG consisting of EO groups has excellent affinity for CO₂ to enhance the solubility selectivity. Thirdly, PEI with abundant primary, secondary and tertiary amine groups reacts reversibly with CO₂ to enhance the reactivity selectivity. Thus, the as-prepared MP-MMMs exhibit excellent CO₂ permeability and CO₂/gas selectivity. The MP-MMM doped with 10 wt% PEG-PEI-GO displays the optimum gas separation performance with a CO₂ permeability of 1330 Barrer, CO₂/CH₄ selectivity of 45 and CO₂/N₂ selectivity of 120, surpassing the 2008 Robeson upper bound lines.