Photobleaching and mineralization of Orange II by oxone and metal-ions involving Fenton-like chemistry under visible light

Cu2+ and Fe3+ significantly improved the Orange II photobleaching and mineralization in the presence of oxone. In the presence of Cu2+ and Fe3+ the oxone needed for the photobleaching and total mineralization of the dye was determined along other solution parameters. In air, the photobleaching of Orange II in solution was observed to be complete within 60 min for Cu2+-ions and 30 min for Fe3+-ions showing a considerable faster kinetics with respect to other treatment systems reported until now. The transition metal-ions used seem to couple with oxone forming high oxidizing sulfate species. A reaction mechanism leading to Orange II photobleaching is suggested through a complex formation between the metal-ion and Orange II involves redox reactions activated by visible light.