A Central Composite Design to Optimize In-Situ Electrochemically Produced Ozone for Removal of Reactive Red 198

This study examined the most important parameters affecting the electrochemical production of ozone and their effects on the destruction of dye Reactive Red 198 (RR198) using anode Ni-Sb-SnO2. Thus, current density, contact time, pollutant concentration, and electrolyte concentration (HClO4) parameters were studied and central composite design was used to optimize the experiments. According to the encoded experiments, the comparison of predicted and obtained results indicates that second-order equations fit surface behavior well. All parameters affected the ozone generation and RR198 removal, but contact time (t) and, among interaction parameters, (time)*(time) played the most roles. Based on variance analysis and fitted equations, the optimal conditions for RR198 removals are: current density of 37.5 mA/cm(2), contact time of 230 s, pollutant concentration of 0.05 mM, and electrolyte concentration of 1.25 M. Under these conditions, the efficacy of current density for generation of ozone and the amount of the generated ozone were, respectively, 28% and 26.4 mg/L. In addition, the voltammetric studies clearly show that at the end of the electrolysis, no electroactive compounds present in the solution. (C) 2018 The Electrochemical Society.