Microwave-assisted hydrothermal synthesis of a&b-oriented zeolite T membranes and their pervaporation properties

By microwave-assisted hydrothermal synthesis (MAHS) method, a&b-oriented zeolite T membranes were firstly prepared on the α-Al2O3 tubes from the a&b-oriented seed layers. By adjusting the pH value of the seed suspension, zeolite T seeds about 8.5 μm long were uniformly deposited on the support surface with their a&b-axes perpendicular to the support surface. After the secondary growth, the a&b-oriented seed layers grew into a&b-oriented zeolite T membranes with the thickness of about 7 μm. A formation mechanism of the membranes was proposed, which could provide general guidance for the preparation of other types of zeolite membranes. The as-synthesized membranes displayed high pervaporation (PV) performance for alcohol/water liquid mixtures. Aiming at the application in the industrial dehydration process, the hydrothermal stability and acid stability of the zeolite T membranes were also investigated.