Electrochemical Oxidation of Wastewater Contaminated with Astrazon Red Violet 3RN Dye on Ti/IrO₂/RuO₂: Evaluation of Process Parameters, Kinetics, and Energy Consumption

The performance of the electrochemical oxidation of wastewater contaminated with Astrazon Red Violet 3RN Dye on Ti/IrO₂/RuO₂ was evaluated under a range of significant process variables: support electrolyte type and concentration, initial dye concentration, pH, current density, and temperature. ARV-3RN dye removal efficiency was over 90% at the high concentrations of NaCl (≥ 5.0 mM) and lower pH values (3.0 ≤ pH≤ ~7.5). At the same time, the temperature increases promoted faster degradation and less energy consumption except at 10°C temperature. While the increase in the initial dye concentration had a negative effect on the removal efficiency (from 99.84% to 65.02%), energy consumption increased from 2.5 kW-h/m3  to 3.25 kW-h/m3. Although the change in applied current density did not cause a significant difference in the removal efficiency (from 99.34% to 92.79%), it caused the energy consumption to increase from 3.10 kW-h/m3 to 25.767 kW-h/m3. Electrooxidation kinetics were evaluated using Pseudo-zero-order, Pseudo-first-order, and pseudo-second-order models. Kinetic data fitted best Pseudo-first-order model. The activation energy (Ea) of the EAOP process calculated using the Arrhenius equation is 13.707 kJ/mol. Thermodynamic parameters ΔH°, ΔS°, and ΔG° evaluated by Eyring's equation calculated 11.196 kJ/mol, -0.1244 kJ/mol, and 47.662 for 293 K, respectively.