: Pervaporation is an effective and energy-efficient membrane separation process for liquid phase separations which are difficult to achieve by conventional separation processes such as distillation and extraction. Because of such unique properties as well-defined system of pore structure, high thermal and chemical stability, zeolite membranes have gained much interest in pervaporation applications. In this research work, NaA zeolite membranes were synthesized on the outer surface of the ?-Al 2 O 3 support tubes for water removal from water/ ethanol and water ethyl acetate mixtures. For this purpose, the zeolite membranes were synthesized by secondary growth method. Since this method involves in support seeding before hydrothermal synthesis, zeolite NaA powder was synthesized to use as seed particles. Conventional heating together with aging of synthesis gel were used for preparing of the particles and the effect of aging time on seed particle size was investigated. The produced powders were analyzed by XRD and SEM. The seeds particle size was about 1.5 ?m. The Seeding process was carried out by vacuum seeding method to form a dense seeding layer on the outer surface of the supports. Different seeding times and concentrations of suspension were used to investigate the effect of these factors on membrane structure and performance. The optimum time and suspension concentration for seeding was found 90 s and 5 g/L, respectively. The membranes were synthesized in a Teflon-lined autoclave at 100° C for a specified time. In some cases, the membrane synthesis was repeated. The structure of as-synthesized membranes was studied by SEM analysis and their performance was evaluated through batch-type pervaporation dehydration of aforementioned mixtures. Ethyl acetate and ethanol concentrations in feed were 98 and 90 wt%, respectively.Results showed that the membrane synthesized for 6 hour with three-stage synthesis had the best performance for dehydration of the mixtures. The SEM and XRD results revealed this sample had a dense and completely intergrown layer of NaA zeolite. The thickness of the zeolite layer was about 45 ?m. The separation factor was more than 10000. Key words NaA zeolite, zeolite membrane, separation, pervaporation, ethanol, ethylacetate
