ZIF-67@polyvinylidene fluoride mixed matrix membranes towards improved hydrogen separation performance

This work is primarily focused on overcoming the limitations of polymeric membranes in achieving the balance between permeability and selectivity of the separation performance. The filler, Zeolitic imidazole framework -67 (ZIF-67) nanoparticles were synthesised in cubical morphology using hexadecyltrimethylammonium bromide (CTAB) as a surfactant via the wet-chemical method. The uniform particles with particle sizes ranging between 120-180 nm were incorporated into the polyvinylidene fluoride (PVDF) matrix to fabricate mixed matrix membranes via the phase inversion method. These mixed matrix membranes were systematically characterised to confirm the chemical, structural and morphological properties of the materials and membranes. Furthermore, the membranes showed a 56.5% improvement in their mechanical properties. The results confirm that 5 wt.% ZIF-67/PVDF membrane showed the best separation results compared to its pure counterpart. The permeability of H₂ gas was reported to be 1,094,511 Barrer, with selectivities of 3.03 for H₂/CO₂ and 3.06 for H₂/N₂. This represents a 210.6% increase in the permeability of H₂ gas. These results demonstrate the influence of ZIF-67 loading in the PVDF polymer matrix along with the potential of ZIF-67/PVDF mixed matrix membranes in the field of hydrogen separation and purification.