Preparations of zeolite ZSM-35 zembranes on porous α-Al_2O_3 tubes
Respectively in the systems of pyrrodine and 1-Butylamine as templates, ZSM-35 type zeolite membranes were hydrothermally synthesized originally in situ on the outer surface of porous α-Al_2O_3 tubes with pore size of 3—5μm.Characterization of the as-prepared membranes with XRD and SEM showed that the prepared membranes were typical zeolite ZSM-35 membranes, on which the zeolite crystals grew interlockedly and compactly and covered completely the outer surface of the ceramic tubes with thickness of about 12—18 μm, and that templates with different structures influenced apparently the morphology of the as-prepared membranes; calcinations of as-synthesized membranes at different temperatures indicated the orientation of crystals on the as-prepared membranes tended to be along (h 0 0) direction with increasing calcination temperatures; and at ambient temperature,H_2, N_2 and C_3H_8 single component permeance tests of the membranes reached the order of magitude 10 -6 with H_2/N_2 and H_2/C_3H_8 selectivity factors respectively above their corresponding ideal Knudsen diffusion factors.