A novel synthesis strategy was developed for the seeding-free preparation of dense LTA zeolite membranes by using 3-aminopropyltriethoxysilane as covalent linker between zeolite membrane and porous Al(2)O(3) support. In a first step, the ethoxy groups of the 3-aminopropyltriethoxysilane react with surface hydroxy groups of the support. In a second step, the 3-aminopropylsilyl groups react with silanols of the zeolite crystals, leading to a "bridge" between the growing LTA zeolite membrane and the support being built to anchor the LTA zeolite layer onto the support. The SEM image and XRD indicate that a dense and pure LTA zeolite membrane with a thickness of about 3.5 mu m can be formed on the alpha-Al(2)O(3) support, and no cracks, pinholes or other defects are visible. The LTA zeolite membrane displays good molecular sieving performance. For binary mixtures at 20 degrees C, the separation factors of H(2)/CH(4), H(2)/N(2), H(2)/O(2) and H(2)/CO(2) are 3.6, 4.2, 4.4 and 5.5, respectively, which are higher than the corresponding value of Knudsen diffusion. Moreover, relative high H(2) permeances of about 3.0 x 10(-7) mol m(-2) s(-1) Pa(-1) can be obtained. (c) 2009 Elsevier B.V. All rights reserved.