CO2 separation of Pebax-based mixed matrix membranes promoted by Cu(Qc)2

In order to improve the CO2 separation performance of Pebax-1657, a metal-organic framework Cu(Qc)2 was prepared which could adsorb CO2 and be introduced into the Pebax-1657 matrix to prepare Pebax/Cu(Qc)2 mixed matrix membranes for CO2 gas separation. The films prepared by the solution casting method were characterized by scanning electron microscopy, thermogravimetric analysis, infrared spectroscopy and X-ray diffraction. Through the gas permeability test of the membrane, the effects of filler content, operating pressure and mixed gas on the gas permeability of the membrane were investigated. The results show that the random and effective stacking of the Cu(Qc)2 in the mixed matrix membranes create highly selective gas transport channels that dramatically enhance CO2/N2 selectivity. Both the CO2 permeability and CO2/N2 selectivity show a trend of first increasing and then decreasing with the increase of Cu(Qc)2 loading. When 3% Cu(Qc)2 filler is added, the CO2/N2 separation performance of the mixed matrix membrane is the best, and the CO2 permeability coefficient and CO2/N2 selectivity are 102 Barrer and 84, respectively. Compared with the pure Pebax-1657 membrane, it has increased by 45.7% and 40.0% respectively, successfully breaking the upper limit of Robeson separation, indicating that the mixed matrix membrane has potential in the application of CO2 separation. © 2021, Chemical Industry Press Co., Ltd. All right reserved.