Effect of incorporating different ZIF-8 crystal sizes in the polymer of intrinsic microporosity, PIM-1, for CO2/CH4 separation

Effective and economical carbon dioxide-methane separation (CO2/CH4) is highly desirable in several industries such as sweetening natural gases renewable gas (RNG) from biogas landfills. Among the different technologies, membrane has been shown to have lower cost of production CH4 losses. In this study, Zeolitic Imidazole Frameworks (ZIF-8) crystals with sizes varying 45 nm 450 were synthesized incorporated polymer intrinsic microporosity, PIM-1, form mixed matrix membranes (MMMs). The structure, morphology, physicochemical properties MMMs characterized by 1H NMR, FTIR, XRD, TGA, SEM. ZIF-8 crystal size was controlled using concentration sodium formate. influence on studied sorption, permeability, aging membranes. 120 particle diameter yielded greatest improvement transport properties; CO2/CH4 selectivity-CO2 permeability 11.4 9700 Barrer compared PIM-1 6.4 9300 respectively. former near Robeson 2008 upper bound, while 1991 bound. After 40 days aging, selectivity increased decreased; changes parallel bounds indicating packing diffusivity selectivity.