Preparation of high performance mixed matrix membranes by one-pot synthesis of ZIF-8 nanoparticles into Pebax-2533 for CO2 separation

Abstract

Herein, an interesting strategy, viz. one-pot synthesis, is proposed to incorporate ZIF-8 nanoparticles into the Pebax-2533 for facile fabrication of MMMs with high permeability and selectivity. Based on characterization analyses, incorporating 8 wt% of ZIF-8 particles via this route increased the fractional free volume (FFV) of the membranes, which contributed to the improvement in the CO2 permeability, avoided the aggregation of the nanoparticles in the polymer matrix, increased the CO2 sorption property due to imidazole linkers, boosted the screening properties owing to intrinsic pore size, thereby improved CO2/CH4 and CO2/N2 selectivities, and in addition, resulted in membranes with desirable thermal properties. As a result, MMM with 8 wt% of ZIF-8 by providing an admirable performance, improved the CO2 permeability and CO2/CH4 and CO2/N2 selectivities of the neat Pebax-2533 membrane from 62.20 Barrer, 11.35, and 24.98 to 158.43 Barrer (+155% enhancement), 27.73 (+144.32%) and 50.76 (+103.21%), respectively. This membrane at an operating pressure of 8 bar overcame Robeson’s upper bound (1991) in the case of CO2/CH4 separation.