A High-Performance Wastewater Treatment System for Orange II Degradation Using a Boron-doped Diamond Electrode and Enhanced by Zeolite-TiO2 Photocatalyst

A wastewater treatment system has been studied which is composed of an electrochemical cell and a photocatalysis unit. A boron-doped diamond (BDD) electrode and TiO2-loaded zeolite (zeolite-TiO2) were used in the electro-photo process, and the joint treatment efficiency was assessed Orange II degradation. The photo-electro treatment of Orange II in aqueous solution was monitored using a combination of HPLC and UV-visible absorption spectroscopy methods. Zeolite improves the photo-efficiency of titanium dioxide due to synergistic effects of the improved generation of active radicals (S2O82- and OH*). Orange II underwent a further rapid degradation by the introduction of zeolite-TiO 2 due to strong adsorption and space effects. The degradation activity to Orange II follows the decreasing order: BDD-zeolite-TiO2 > BDD > zeolite-TiO2. The degradation rate was seen to increase with OH* radicals resulted from S2O82--which produced on the BDD surface and by the zeolite-TiO2 catalyst. Orange II could be almost completely degraded to CO2 and H2O after 180 min of electrolysis time by this joint treatment system.