Rapid and complete oxidation of acetaldehyde on TiO2 photocatalytic filter supported by photo-induced activated hydroxyapatite

The new TiO2 photocatalytic filter supported by photo-induced activated hydroxyapatite (HAp Ca-10(PO4)(6)(OH)(2)) was developed and the complete oxidation of acetaldehyde on the filter was investigated. The photocatalytic filter was fabricated by coating TiO2 and HAp on the porous ceramics body. In the decomposition of acetaldehyde using this composite filter, CO2 generation came to maximum at 20 min after starting of UV (254 nm) irradiation and the value was the stoichiometric to the complete oxidation. The rapid and complete oxidative decomposition of acetaldehyde can be achieved using the new photocatalytic composite filter in spite of the very small contact time, about 0.4 s through the filter and one path method. This effect would not be explained alone by the absorption capacity of HAp for acetaldehyde. Synergic and composite effect of HAp followed by radical formation under light is maximum at 254 nm. (c) 2005 Elsevier B.V. All rights reserved.