A novel mixed matrix membrane (MMM) was fabricated by incorporating micro-sized nano-porous sodium zeolite-Y (NaY zeolite) into Matrimid®5218 matrix. The filler and the prepared membranes were characterized by X-ray diffraction (XRD), Fourier transform infrared-attenuated total reflectance (FTIRATR), scanning electron microscopy (SEM), and thermal gravimetric and derivative thermal gravimetric (TG/DTG) analyses. The effects of filler content (0–20 wt%), feed pressure (2–12 bar), operating temperature (35–75 C) and mixed feed gas on CO2/CH4 transport properties of Matrimid/NaY were investigated. The results revealed that the Matrimid/NaY (15 wt%) displayed a CO2 permeability of 17.52 Barrer, more than two-fold increase with respect to the NaY-free counterpart. The corresponding CO2/CH4 selectivity was increased from 36.3 for Matrimid to 43.3 for Matrimid/NaY (15 wt%), (about 20%). The CO2 permselectivities of MMMs were greater than that of the Matrimid over the entire pressure range. As the operating temperature increased from 35 to 75 C, CH4 permeability increased about 175% and 215% for Matrimid and Matrimid/NaY (15 wt%), respectively. While the CO2 permeability enhanced about 78% and 98%. The corresponding decreases in the CO2/CH4 selectivities were 35.27% and 37.14%, respectively. Moreover, the mixed gas experiment results indicated that CO2 permeability and CO2/CH4 selectivity for all membranes were lower than those of pure gas experiments, but with less severity for MMMs. The best CO2-selective membrane, Matrimid/NaY (15 wt%), represented the CO2 permeability of 15.19 Barrer with CO2/CH4 selectivity of 39.5 for a 10/90 vol% mixture of CO2 and CH4.
