BACKGROUND: Natural gas is essential for the world's supply of energy due to its economic viability and environmental sustainability in producing adequate amounts of clean energy. However, the removal of CO2 as an undesirable impurity remains challenging in natural gas purification. In this work, high performance dense mixed matrix membranes (MMMs) containing a low loading (<2 wt) of zeolitic imidazolate framework 8 (ZIF-8) and polysulfone (PSF) were prepared via simple solvent evaporation method and single solvent for the removal of CO2 from CH4. RESULTS: Significant enhancements in CO2 permeability and CO2/CH4 ideal selectivity were obtained for the resultant MMMs as compared to the neat PSF membrane. The highest CO2 permeability of 33.57 Barrer and CO2/CH4 ideal selectivity of 39.03 were achieved for a PSF membrane loaded with 1 wt of ZIF-8; these values were 514 and 161 higher than those obtained for the neat PSF membrane, respectively. Furthermore, MMM embedded with 1 wt of ZIF-8 demonstrated CO2 plasticization pressure up to 16 bar, which is equivalent to an 100 increment of the value obtained for the neat PSF membrane. CONCLUSION: Overall, MMMs fabricated in this work demonstrated a significant improvement of CO2 separation from CH4 compared to the PSF-based MMMs reported in the literature, where most of the reported MMMs contain high loading of fillers up to 30 wt. Therefore, the MMMs fabricated in this work are ready to be further exploited for application in gas separation industries. © 2021 Society of Chemical Industry (SCI). © 2021 Society of Chemical Industry (SCI).