Synthesis and characterization of high performance NaA zeolite-polyimide composite membranes on a ceramic hollow fiber by dip-coating deposition Original Research Article

NaA zeolite membranes were synthesized on a porous seeded α-Al2O3 ceramic hollow fiber substrate via microwave heating method. Dense intergrown NaA zeolite-polyimide (PI) composite membranes were prepared by dip-coating with polyamic acid solution and imidization process on the NaA zeolite membranes. The composite membranes were characterized by XRD, FT-IR, SEM, gas permeation and pervaporation tests. The differences in morphology, structure and gas permeability between NaA zeolite and NaA zeolite-PI composite membranes were explored. XRD results show that only NaA zeolite emerges on the support, and FT-IR results show that PI has been successfully synthesized on NaA zeolite membranes surface. The SEM images show that the particles are twinborn by well intergrowth on the composite membrane surface. Gas permeation tests on H2, O2, N2 and C3H8 under different temperatures display that the permeance of H2 on the NaA zeolite-PI composite membranes is lower than that of NaA zeolite membranes, and the permselectivity of H2/C3H8 on the former membranes is higher than that of the latter. Pervaporation experiments of the as-synthesized membranes on various alcohol mixtures indicate that the maximum selectivity of NaA zeolite-PI composite membranes on EtOH/H2O solution with the water content of 10 wt.% was much higher.