Electrochemical Degradation of Acid Yellow 23 by Anodic Oxidation—Optimization of Operating Parameters

Abstract

In this study, the electrochemical oxidation (EO) process was implemented and optimized to effectively decolorize and degrade wastewater containing Acid Yellow 23 (Y23). The experiments were carried out in a laboratory-scale batch cell reactor, with monopolar configuration of electrodes, made of graphite (anode) and titanium (cathode). The response surface methodology (RSM), coupled with Box-Behnken experimental design (BBD), was used to evaluate the single and interactive effects of different variables of the EO process on (1) degradation percentages of both chemical oxygen demand (%DCOD) and color (%DC) and (2) energy consumption (EC). Thus, the following experimental factors were considered: initial dye concentration (40–100 mg/L), current density (10–20 mA/cm2), and conductivity (1,000–4,000 μS/cm). Thus, the subsequent conditions were found to be optimal for decolorization and degradation of Y23: initial dye concentration = 100 mg/L; current density = 20 mA/cm2; and conductivity = 4,000 μS/cm. At these conditions, the EO process allowed to reach approximately 99% of color degradation and 76% of COD degradation. Because NaCl was used as an electrolyte, chorine formation was monitored, and its effect on %DC and %DCOD was also evaluated.