Fabrication and characterization of polysulfone/polyimide–zeolite mixed matrix membrane for gas separation

In this study the gas separation performance of polyimide/polysulfone (PI/PSF) mixed matrix membranes filled with zeolite ZSM-5 particles is investigated. The membranes are prepared by solution-casting method and utilized to determine the permeation rates of N2, O2, CO2 and CH4 through pure polymers as well as composite membranes.The membranes are characterized by SEM, TGA and FTIR. The effects of polymers ratio and weight fraction of zeolite on permeation and selectivity of the gases are discussed. Polymers ratio in the mixed matrix have assumed values of 100% PSF, 70/30 (PSF/PI), 50/50, 30/70 and 100% PI while ZSM-5 loadings are varied between 0 and 20 wt.%. SEM results showed that fabricated membranes have homogeneous structure. With pure polyimide membrane, O2 permeability increased from 0.69 Barrer for membrane without zeolite up to 0.73 and 0.89 Barrer for membranes with 10% and 20% zeolite, respectively. Within blended matrices, the minimum permeability (maximum selectivity) and the most homogeneous matrix structure were related to the matrix with 50/50 weight percent of two polymers.

► Transport properties of different polysulfone/polyimide filled with ZSM-5 are investigated for N2, O2, CO2 and CH4.
► The polymers were miscible and formed completely homogeneous matrices.
► The fabricated MMMs offered higher permeability and acceptable selectivity in comparison with plain membranes.
► MMMs with 50/50 ratio have the highest selectivity and lowest permeability among all blending ratios for all gases.
► Membranes with larger zeolite loadings and higher polyimide portions have more thermal stability.