Matrimid®/polysulfone blend mixed matrix membranes containing ZIF-8 nanoparticles for high pressure stability in natural gas separation

In mixed gas (50/50 mol% CO2/CH4) experiments, the pure PI/PSF membrane and the MMMs did not show plasticization over the pressure range investigated, as confirmed by a constant mixed gas CH4 permeability and nearly constant selectivity with pressure. While the pure PI and PI-ZIF-8 MMMs showed the plasticization behavior. Comparing the mixed gas performance of PI/PSF-ZIF-8 membranes with that of pure PI/PSF membranes at high pressures an increase of 197% in CO2 permeability and 30% in CO2/CH4 selectivity was obtained. These results showed that the combination of polymer blending and the mixed matrix membrane approach offers a simple and economically versatile tool to approach higher CO2 permeabilities and CO2/CH4 selectivities while maintaining a stable separation performance in processes involving higher CO2 partial pressures.