Preparation of alumina membrane from aluminium chloride

A new method for the preparation of γ-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 γ-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 H2/N2 and H2/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 °C were 3.7 nm, 0.18 ml/g and 176.9 m2/g, respectively.