Synthesis of Composite Membranes using Melamine Modified Zeolitic Imidazolate Framework for CO2/CH4 Separation

With fossil fuels being the primary source of energy with currently growing demands, it is important to shift towards clean, renewable energy sources such as biogas that has the potential to fulfill partial energy needs. However, biogas needs to be stripped of CO2 to increase its methane content for it to be used as an energy source. Membrane technology for the separation of CO2 from methane is extremely promising because of its higher separation efficiency without the generation of any secondary waste. In this study, different concentrations i.e. 1, 2 and 3 wt. % of melamine zeolitic imidazolate framework (ZIF-8) are incorporated into cellulose acetate (CA) as an additive to form mixed matrix membranes (MMMs), while polysulfone (PSF) is used as the support. The mechanical strength, permeance and selectivity of the membranes are observed to increase with increasing ZIF-8 concentrations, as well as with feed pressure. 3 wt. % ZIF-8 membranes exhibit maximum enhancement of 8.63% in CO2 permeability at 8 bar, while the highest selectivity obtained at same conditions is 14.7.