Mixed matrix membranes on the basis of Matrimid and palladium-zeolitic imidazolate framework for hydrogen separation

Gas separation membranes with enhanced performance were developed by the introduction of nanosized palladium particles. In this study, gas separation performance of Matrimid membrane incorporated with palladium-zeolitic imidazolate framework-8 (Pd@ZIF-8) particles, prepared by solution casting method, has been investigated. ZIF-8 nanoparticles were first synthesized using rapid room-temperature method and Pd@ZIF-8 nanoparticles were prepared through an assembly approach. The synthesized nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometry (XRD), and Fourier transform infrared equipped with attenuated total reflection (FTIR-ATR). TEM images exhibited that the incorporated Pd nanoparticles are well confined within the ZIF-8 crystals. The prepared mixed matrix membranes (MMMs) with various Pd@ZIF-8 contents (0-30 wt%) were characterized by SEM and XRD. All the modified membranes exhibited enhanced gas separation performance for selected gas pairs compared to a neat Matrimid membrane. The highest performance was observed for nanocomposite membranes with incorporation of 30 wt% of Pd@ZIF-8 into Matrimid which resulted in 72% increase in H-2 permeability. The separation factors of H-2/CO2, H-2/CH4 and H-2/N-2 were improved from 3.25, 126.13, 95.21 for Matrimid/ZIF-8 to 5.82, 228.2 and 169.1 for Matrimid/(Pd@ZIF-8) membranes, respectively. Finally, the increase in feed pressure significantly improved the separation performance quality in all the membranes.