ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The synthesis and characterization of supported and non-supported membranes of γ-Al2O3, TiO2 and their binary combinations are described. Non-supported γ-Al2O3 and TiO2 membranes were prepared from colloidal dispersions (sols) of boehmite and titania, respectively. Stable binary sols were also prepared by mixing boehmite and titania sols under appropriate pH conditions, and these were used to prepare binary (γ-Al2O3/TiO2) membranes. Supported γ-Al2O3, TiO2 and binary membranes were made by the slip-casting process using the same sols. The membrane layers had, after calcination, a thickness of 3–6 μm depending on the dipping conditions, and an average pore diameter of ∼-3–4 nm with a narrow pore-size distribution. The structural transformation of titania from the anatase to the rutile phase was retarded by performing the hydrolysis in the presence of sulphate ions. Polyvinyl alcohol was added to the sols to strengthen the gel network during the drying and calcination process. This resulted in a less critical and more controllable membrane formation process. Multiple dipping (e.g. to repeat the dipping, drying and calcination steps) appeared to be a technique by which (i) defected layers could be repaired; (ii) thick membrane layers could be prepared; and (iii) multilayer membranes consisting of layers of different components could be prepared.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01197657
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