ZIFs materials exhibit higher adsorption properties toward CO2 . The diffusivity of CO2 is two times higher than that of CH4 . However, there are strong interactions between CO2 molecules and the functional groups of ZIFs, including hydrogen bond formation. These properties lead to high adsorption capacity and selectivity toward CO2 over other gases. Furthermore, modification can further enhance adsorption capacity and selectivity via an amendment (Table ) . ZIFs can be synthesized using an environmentally friendly solvent such as water. They exhibit high