Water treatment for color and COD removal by electrochemical oxidation on boron-doped diamond anode

The electrochemical oxidation of synthetic wastewater which contains biazo dye [amido black (AB)] on boron-doped diamond anode, "BDD anode," was experimentally investigated to determine the influence of several operative parameters on the performance of the process. The study focalized on the effect of studied parameters on discoloration process and the degradation of the aromatic part of the dye molecule. Two distinct pathways with two different kinetics were observed. The decrease of pH improves the discoloration rate and the degradation of aromatic by-products after 90 min of electrolysis. The increase of current density has a considerable effect on discoloration and a little less effect on the aromatic derivative degradation. Hypochlorite electrogenerated from chloride addition exceptionally accelerates the discoloration, but it does not degrade aromatic derivatives as efficiently. It was observed that nitrates addition generates under electrolysis other derivates of AB as different colors than the dye one. The current efficiency depends very little on the initial pH; however, higher energy consumptions are obtained.