ZIF-8 @polycarbonate nanocomposite membranes for improved permeability and selectivity for hydrogen gas

Through this work, we are reporting high-performance ZIF-8 @polycarbonate nanocomposite membranes with satisfactory structural stability for improving the gas separation performance. ZIF-8 nanoparticles were synthesised using the wet chemical route with cubic morphology and controlled size using CTAB as a surfactant. The membranes were prepared using the solution casting method by adding ZIF-8 filler at various concentrations. The synthesised filler material and MMMs were characterised through X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and RAMAN spectroscopy techniques. The gas separation measurements were taken using H₂, CO₂, and N₂ gas in the purest form. The SEM results confirm the formation of spherulite-like morphology with the addition of ZIF-8 due to the crystallisation of the polymer, which increased the membrane's free volume and opened up additional pathways for the transportation of the gas molecules. The gas separation results confirmed that the 15 wt% ZIF-8/PC nanocomposite membrane showed the maximum H₂ permeability of 180,970 barrer with an increment of 316.03%, while H₂/CO₂ and H₂/N₂ selectivity showed the increments of 89.43% and 103.64%, respectively. Therefore, this PC/ZIF-8 system seems to be a promising approach to developing new H₂ selective membranes with high gas permeability and gas selectivity values.