Oxidative degradation of dyes by ultraviolet radiation in the presence of hydrogen peroxide

The decolorization and mineralization of some azo and anthraquinone dyes by photoactivated hydrogen peroxide has been studied. The degradation process seems to occur according to a similar mechanism for all the selected dyes. Decolorization is complete in a relatively short time and follows apparent first order kinetics, whereas mineralization requires longer irradiation times. Initially fluorescent intermediates are generated in all cases by hydroxylation of the studied compounds. A simple kinetic model, describing adequately the process, has been proposed; pH does not influence significantly the process in the range going from 3 to 9.