Highly hydrogen permselective ZIF-8 membranes supported on polydopamine functionalized macroporous stainless-steel-nets

Inspired by the bio-adhesive ability of the marine mussel, highly hydrogen permselective ZIF-8 membranes were prepared on polydopamine functionalized stainless-steel-nets (SSNs). With polydopamine functionalization of SSNs under mild conditions, the nucleation and growth of well-intergrown ZIF-8 membranes were promoted through the formation of strong non-covalent and covalent bonds, which was helpful to enhance the membrane's separation selectivity while maintaining high permeance. For binary mixtures at 100 °C and 1 bar, the mixture separation factors of H₂-CO₂, H₂-N ₂, H₂-CH₄ and H₂-C₃H ₈, were found to be 8.1, 15.0, 23.2 and 329.7, which by far exceed the corresponding Knudsen coefficients and those of the as-reported ZIF-8 membranes. The ZIF-8 membranes also displayed high permeances, with the H ₂ permeance higher than 2.1 × 10^-5 mol m ^-2 s^-1 Pa^-1 due to the high void volume of the SSNs.