Cellulose acetate-based membranes by interfacial engineering and integration of ZIF-62 glass nanoparticles for CO separation.

Composite membranes typically used for gas separation are susceptible to interfacial voids and CO plasticization which adversely affects the gas permeation performance. This paper evaluates routes towards the enhancement of CO permeation performance and CO plasticization resistance of composite membranes using non-stoichiometric ZIF-62 MOF glass and cellulose acetate (CA). Single and mixed gas permeation results, obtained with CO and CH, demonstrate that the presence of ZIF-62 glass in CA polymer enhanced the CO permeability and CO/CH ideal selectivity from 15.8 to 84.8 Barrer and 12.2-35.3, respectively. The composite membrane loaded with 8 wt% of ZIF-62 glass showed the highest CO permeability and CO/CH ideal selectivity of 84.8 Barrer and 35.3, which were 436.7% and 189.3% higher compared to the pristine CA membrane, respectively. A CO plasticization pressure of 26 bar was achieved for the composite membranes, which is 160% higher compared to the pristine CA membranes, at about 10 bar. The mechanisms for the materials stabilization and greater separation performance were attributed to higher pore size (7.3 Å) and significant CO adsorption on the unsaturated metal nodes followed by metal cites electrostatic interaction with CO. These findings confirm the potential of ZIF-62 glass materials as promising materials solutions towards the design of composite membranes for CO separation at industrial scale.