Electroplating wastewater treatment by electro-oxidation using synthesized new electrode: Experimental, optimization, kinetics, and cost analysis

Abstract

The present work studied electroplating wastewater treatment by the electro-oxidation (EO) method through a new Ti/TiO2-GO-SnO2 electrode in a once-through continuous mode. The Ti/TiO2-GO-SnO2 electrode was synthesized using an anodic oxidation technique and characterized by electrochemical characterizaftion. Response Surface Methodology (RSM) employing a Box-Behnken Design (BBD) model was utilized to optimize pH (3−7), current density (j = 16.72–50.16 mA/cm2), and time (t = 30–130 min) for removal of electroplating effluents and energy consumption. At the optimum condition, the values of the responses R1 (% Cr(VI) removal), R2 (% Zn removal), R3 (% COD removal), and R4 (energy consumption) were found to be 97.55%, 95.66%, 87.32%, and 14.97 kWh/m3, respectively. The effect of reactive species scavengers on removing electroplating effluents has been studied. The kinetics and cost analysis were also carried out under optimal conditions. Once-through continuous experiments were carried out at different flow rates to determine the viability of the process at industrial or pilot scale applications. The synthesized electrode proved highly reusable, maintaining durability even after sixty cycles of usage. Toxicity analysis showed that EO has the potential to detoxify electroplating effluents. The observed results confirm that the EO with Ti/TiO2-GO-SnO2 electrode is low-cost and effective for removing electroplating effluents.