Studies on the electrochemical degradation of Acid Orange II wastewater with cathodes modified by quinones

The electrochemical oxidation of dye wastewater with the cathode modified by quinones has been investigated. Under the optimal conditions, the decolorization efficiency can reach 96.0% after 120 min. The addition of tert-butanol significantly decreased the decolorization efficiency, suggesting the involvement of ?OH radicals in the decomposition of H₂O₂. A potential difference may result in a quinone radical on the cathode which can catalyze the reduction of O₂ to H₂O₂. UV–vis spectrum and GC/MS analysis revealed that the dye molecule was firstly initiated by the cleavage of NN, and decomposed to aromatic intermediates, further degraded to ring opening products and finally mineralized.