Performance of electrochemical oxidation of Disperse Yellow 3 dye over BDD anodes

Electrochemical oxidation is a promising approach for developing viable alternatives to treat polluted waters and effluents from various sources, including industrial and domestic wastewater. Since azo dyes represent an important part of the dyes used in the textile industries and because they are toxic and difficult to be treated by conventional methods, in this study, we investigate the electrodegradation of the azo dye Disperse Yellow 3 (DY3) on a boron-doped diamond (BDD) anode. Byproducts are monitored by mass spectrometry and the electrogenerated hydroxyl and sulfate free radicals are analyzed by electron paramagnetic resonance spectroscopy (EPR). Hydroxyl radical formation during the electrolysis in nitrate medium is identified by EPR technique whereas in the sulfate medium, sulfate radical is identified in addition to hydroxyl radicals. The use of different electrolysis conditions allows confirming the ability of the electrochemical method to degrade the azo dye using BDD electrodes. The catalytic effectiveness for the DY3 electrodegradation in the presence of sulfate is around 8 times more efficient than in the presence of pure nitrate solution, which is attributed to the sulfate radical formation that largely influences the BDD electroactivity, accelerating degradation.