Microwave synthesis of LTA zeolite membranes without seeding

A new method called "in-situ aging—microwave synthesis" was developed for zeolite membrane synthesis. High quality LTA zeolite membranes were successfully microwave-synthesized without seeding by this method. It was found that the formed zeolite layer was composed of sphere grains with undefined crystal facets. The necessity of in-situ aging was discussed. The effects of synthesis parameters including in-situ aging temperature, time and microwave heating time, on the characteristics and separation performance of the as-synthesized membranes were investigated. It was found that in-situ aging temperature and microwave heating time had the most significant influences on the synthesis. LTA zeolite membranes synthesized by "in-situ aging—microwave heating" method showed superior gas permeation properties (permeance of H2 = 1.71 × 10−7 mol m−2 s−1 Pa−1, permselectivities for H2/N2 and H2/C3H8 were 5.60 and 9.17, respectively). Through this method, LTA zeolite membranes with excellent pervaporation performance were prepared with high reproducibility. This convenient and effective method paved a promising way toward mass production of LTA zeolite membranes.