Preparation and characterization of high-flux T-type zeolite membranes supported on YSZ hollow fibers

T-type zeolite membranes were prepared on thin yttria-stabilized zirconia (YSZ) hollow fiber substrates by secondary growth method. Prior to membrane synthesis, the outer surface of YSZ hollow fibers were planted with T-type zeolite seeds. Extensive investigation on membrane synthesis was carried out in terms of seeding method, synthesis temperature, crystallization time and precursor composition. High-quality hollow fiber T-type zeolite membranes were synthesized at 100°C for 40h using milk-like aluminosilicate gel (SiO₂:Al₂O₃:Na₂O:K₂O:H₂O=1:0.05:0.26:0.09:17 in mol) as a synthesis precursor. The as-synthesized membranes via the seeding approach of rubbing had well-intergrown zeolite layers with a thickness of ~12μm, which displayed high permeation flux for dehydration of organics. Typically, a water permeation flux of 7.36kgm^-2h^-1 with separation factor of >10,000 was obtained for dehydration of 90wt% isopropanol solution at 75°C. The membrane synthesis via the seeding approach of vacuum-coating could produce hollow fiber T-type zeolite membranes in batch scale. High acid resistance for the membrane material was confirmed by dehydration of propanal solution with pH~4. Moreover, hollow fiber membrane modules with ca. 0.1m² membrane area were fabricated and assembled for propanal dehydration to evaluate the technical feasibility.