Improvement of Co2/Ch4 Separation Performance Using Amine Modified Zif-8 Mixed Matrix Membrane

Amine modified mixed matrix membranes (A-Ms) have been developed with improved anti-plasticization behavior at high pressure for natural gas purification. The neat PSf hollow fiber membrane and amine modified zeolitic imidazole framework-8 (A-ZIF-8) blended polysulfone (PSf) membranes have been fabricated at different A-ZIF-8 loadings for natural gas purification. The prepared membranes were evaluated using field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and gas separation performance. The low loading of A-ZIF-8 nanoparticles improved thermal stability, glass transition temperature and surface roughness. A-Ms fabricated with 0.25 wt% A-ZIF-8 were tested using pure gases with a significant improvement of 50, 72 and 69% in CO2/CH4 selectivity compared to the neat membrane, and an increase of 33, 78 and 77% in CO2/CH4 selectivity compared to the virgin ZIF-8 based membrane at 6, 8 and 10 bar (g) feed pressure, respectively. However, the further increase in the A-ZIF-8 loading has reduced the separation performances. Therefore, this excellent gas separation performance shows improved anti-plasticization behavior at high feed pressure which is rarely investigated. Hence, the promising results obtained at high feed pressure in this study demonstrated the potential of A-ZIF-8 based hollow fiber membrane for natural gas purification at high pressure.