International Journal of Photoenergy 
Volume 1 (1999), Issue 2, Pages 85-88
doi:10.1155/S1110662X99000161

Photocatalytic degradation of some toxic analytical reagents with TiO2

M. M. H. Khalil,1 A. A. Abdel-Shafi,1 and M. S. A. Abdel-Mottaleb1,2

 1Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
2Photoenergy Center, Ain Shams University, Abbassia, Cairo 11566, Egypt

Abstract

Photodegradation processes of two azo dyes at TiO2/H2O interface under visible and ultraviolet light irradiation are investigated with different experimental techniques (absorption and fluorescence spectroscopy as well as total organic carbon analysis). Measuring their fluorescence spectra monitored the generation of some degradation intermediates. The photodegradation rate depends on dye structure and pH of the dispersion. The rate was found to be enhanced by increasing dissolved oxygen concentrations in the medium. The mechanism of the photodegradation process under uv-visible light illumination involves an electron excitation into the conduction band of the TiO2 semiconductor leading to the generation of very active oxygenated species that attack the dye molecules leading to photodegradation.