Photocatalytic Degradation of Azo Dye Reactive Orange 16 by TiO2

Photocatalytic degradation of hydrolyzed reactive orange 16 (RO16) using titanium dioxide (TiO2) was analyzed in our study. The effects of various parameters, such as photocatalyst amount, RO16 concentration, light intensity, and temperature on photocatalytic degradation were investigated. Decolorization of hydrolyzed RO16 resulted in an decreasing of toxicity (EC50 = 76.54 +/- 2.16). It was found that the decolorization efficiency was 87% after 20-min reaction and 100% after 80-min reaction. The total mineralization was 70% after 20 min and nearly 100% after 120 min, respectively. The results indicate that color degradation was faster than the decrease of total organic carbon. The photocatalytic degradation process was well described by first-order reaction. The final mineralization product was acetamide and the intermediate products were identified by gas chromatography-mass spectroscopy.