Synthesis of NaA Zeolite Membrane on Seeded Substrate and Its Characterization

A dense and defect free NaA zeolite membrane with 4～5 μm thickness on the seeded macroporous α Al 2O 3 substrate with submicron seeds was prepared successfully by the secondary growth from clear solution. The substrate, seed layer formed by coating and NaA membrane synthesized by regrowth were characterized by TEM, SEM and XRD. The seed layer with uniform crystal size of 150 nm on the substrate favored the formation of a continuous top layer zeolite membrane during the growth. The substrate surface could be greatly improved, and a uniform and smooth seed layer with ca 3 μm thickness was formed by seeding. The crystal of the zeolite membrane was cubic and well intergrown. The substrate, seed layer and membrane were firmly combined together. The synthesized membrane was evaluated by single gas permeation, and showed good molecular sieving property. This method may be useful for the preparation of other type zeolite membranes on macroporous α Al 2O 3 substrate.