An B-Al-MFI-type zeolite membrane was in-situ synthesized on the surfaces of a boron-silicon porous glass disc by substrate self- transformation in the vapor of ethylamine (EA) and H~2O. Both XRD and SEM show that the zeolite crystals on the surfaces of the orous glass disc are in random orientation. The crystal sizes in the membrane are in the range of ca. 15～25μm. The thickness of the membranes in the form of one-crystal layer is ca. 10·20μm. The permeability of the calcined B-Al-MFI-type zeolite membrane to O~2 and N~2 are 0.985×10^-^8 and 0.15×10^-^8 mol/(m^2·s·Pa) respectively. The calculated ideal selectivity of O~2/N~2(0.63) is obviously lower than that for Knudsen behaviour (0.94) and for the substrate (0.91).

Key words: ALUMINIUM, BORON, ZEOLITE, X-RAY DIFFRACTION ANALYSIS, SCANNING ELECTRON MICROSCOPES