Mixed Matrix Membranes Based on Metal–Organic Frameworks with Tunable Pore Size for CO2 Separation

Two isomorphous MOFs (Ni2(l-asp)2bipy and Ni2(l-asp)2pz) with different pore sizes were incorporated into poly­(ether-block-amide) (Pebax-1657) to prepare the mixed matrix membranes (MMMs) with gas permeation properties for CO2, H2, N2, and CH4. Different loading ratios of MOFs with mass percentage from 10% to 30% were studied. Compared with the pure polymer membrane, the as-synthesized two series of MMMs showed improved CO2 permeability and CO2/H2 selectivity. The highest CO2 permeation property was achieved by Ni2(l-asp)2­bipy@­Pebax-20 of 120.2 barrers with an enhanced CO2/H2 selectivity of 32.88 compared with 55.85 barrers and 1.729 of the pure polymer membrane, respectively, which makes it a potential candidate for future applications in CO2 capturing.