Photodestruction of Acid Orange 7 (AO7) in aqueous solutions by UV/H2O2: influence of operational parameters

The photodestruction of Acid Orange 7 (AO7), an anionic acidic dye, was studied in the UV/H2O2 process. H2O2 and UV light have a negligible effect when they were used on their own. Removal efficiency of AO7 was sensitive to the operational parameters such as initial H2O2 concentration, initial AO7 concentration, pH and different light sources. The photodestruction of AO7 was inhibited by addition of EtOH as an electron scavenger. The semi-logarithmic graphs of the concentration of AO7 versus time (t<30 min) were linear, suggesting pseudo-first order reactions (k(optimum)=0.105 min(-1)). A simple kinetic model is proposed which is in agreement with experimental results.