Kinetic study of decolorization process of acid orange 7 from aqueous solutions using nanosized CuO-ZnO/visible light

ZnO has been extensively investigated as a semiconductor photocatalyst due to its wide direct band gap (3.2 eV), which is the same with TiO2 [1]. However, this semiconductor can only absorb a small portion of solar spectrum in the UV region, which results in the low photocatalytic efficiency [2]. So, in order to improve the efficiency further, researchershave loaded some metals on semiconductors surface for modification [1]. Decolorization kinetics of acid orang 7 (AO7) at different temperature and basic condition were studied over 90 min periods. The obtained data were treated according to tow various rate models. Our results showed the pseudo second order model was the most suitable on the all conditions.