Functionalized KIT-6/Polysulfone Mixed Matrix Membranes for Enhanced CO₂/CH₄ Gas Separation

The development of mixed matrix membranes (MMMs) for effective gas separation has been gaining popularity in recent years. The current study aimed at the fabrication of MMMs incorporated with various loadings (0-4 wt%) of functionalized KIT-6 (NH₂KIT-6) [KIT: Korea Advanced Institute of Science and Technology] for enhanced gas permeation and separation performance. NH₂KIT-6 was characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and N₂ adsorption-desorption analysis. The fabricated membranes were subjected to FESEM and FTIR analyses. The effect of NH₂KIT-6 loading on the CO₂ permeability and ideal CO₂/CH₄ selectivity of the fabricated membranes were investigated in gas permeation and separation studies. The successfulness of (3-Aminopropyl) triethoxysilane (APTES) functionalization on KIT-6 was confirmed by FTIR analysis. As observed from FESEM images, MMMs with no voids in the matrix were successfully fabricated at a low NH₂KIT-6 loading of 0 to 2 wt%. The CO₂ permeability and ideal CO₂/CH₄ selectivity increased when NH₂KIT-6 loading was increased from 0 to 2 wt%. However, a further increase in NH₂KIT-6 loading beyond 2 wt% led to a drop in ideal CO₂/CH₄ selectivity. In the current study, a significant increase of about 47% in ideal CO₂/CH₄ selectivity was achieved by incorporating optimum 2 wt% NH₂KIT-6 into the MMMs.