A new method for the preparation of gamma-alumina membranes from aluminium chloride was investigated in this paper. Boehmite sol was synthesized by an anionic exchange method, which could offer OH--ion and simultaneously remove Cl--ion. Boehmite sols were then deposited on the inner surface of the hollow fiber supports by a filtration technique. The thermal evolution, phase transformation, structure, morphology and pore size distribution of the gamma-alumina membranes were characterized by thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and nitrogen isothermal adsorption measurement. SEM images showed that the membranes were defect-free. Gas permeability tests suggested that the obtained membranes possessed gas selectivity, and its separation factor for H-2/N-2 and H-2/CH4 were 3.31 and 2.25 at 0.1 MPa, respectively. The most concentrative pore diameter, pore volume and specific surface area of an unsupported membrane calcinated at 600 degrees C were 3.7 nm, 0.18 ml/g and 176.9 m(2)/g, respectively. (c) 2005 Elsevier B.V. All rights reserved.