A New Inorganic Membrane: TiO2 Ultrafilter Based on Functionally Graded Porous Alumina


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The fabrication of thin nanoporous TiO2 layers (thickness < 2 μm) on functionally graded porous alumina (thickness = 2 mm) is reported for the first time. The membrane is produced by dip coating TiO2 sols on the alumina support. The alumina porous support is produced using centrifugal casting with an acceleration of 3000g .The average pore size of the support is ca. 0.5 μm while its upper surface on which the membrane layer is deposited has an average pore diameter of 0.38 μm and average porosity of 10.7 %. The sol is produced by the peptization technique using tetrapropylorthotitanate as precursor. For the first time, a synthesis procedure has been implemented which allows the production of TiO2 sols with average particle sizes from12 to 22 nm. Using the BET technique, the average pore size and meso-porosity of the unsupported sintered TiO2 membranes as a function of sintering temperature and ZrO2 impurity concentration (0.0, 0.2, 0.6 and 1.0 wt. % of ZrO2) have been determined. The kinetics of the membrane layer anatase to rutile transformation reaction has been investigated as a function of ZrO2 impurity concentration introduced to the TiO2 sol during its preparation. The lack of macrocraks in the ultrafilter layer of the sintered composite was confirmed using the gas permeability and SEM techniques. The main outcome of this work is that the support has an outstanding low surface roughness (< 0.4 μm) allowing deposition of a defect free single layer of TiO2 in one step



Edited by:

Prof. Andreas Öchsner and José Grácio




C. Falamaki and J. Veysizadeh, "A New Inorganic Membrane: TiO2 Ultrafilter Based on Functionally Graded Porous Alumina", Materials Science Forum, Vol. 553, pp. 239-244, 2007

Online since:

August 2007




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