Enhanced separation performance of ZIF-8 membrane through gas-assisted surface ligand exchange modification

A new approach for ZIF-8 membrane modification by surface ligand exchange using 5,6-dimethylbenzimidazole is presented to clarify the exchange mechanism. One hour of ZIF-8 membrane modification enhances both propylene permeance and (propylene/propane) separation factor by about 11 % and 39-72 %, respectively, depending on the membrane's initial quality. The best modified ZIF-8 membrane shows propylene permeance of 6.34 x 10-9 mol/(m2s.Pa) and selectivity of 188.6. This improvement contrasts with previous studies that reported a decrease in permeance for modified membranes, thereby supporting the advancement of ZIF-8 membranes toward commercialization.