Transforming coking wastewater: Breakthrough COD reduction with Ti/RuO2-IrO2 anode electrocatalysis

In recent years, advanced oxidation technologies (AOPs) that utilize the oxidative power of free radicals generated by chemical or physical pathways to degrade harmful organic compounds in aquatic media have attracted the attention of researchers. Recent advances in electro-catalytic oxidation (ECO) in APOs have made it possible to almost completely degrade the chemical oxygen demand (COD) of organic matter in coking wastewater. In this paper, comparative analysis with Titanium/Tantalum Pentoxide (Ti/Ta2O5) and boron-doped diamond (BDD) electrodes indicated that the iridium oxide-coated titanium material (Ti/RuO2-IrO2) electrode had superior performance. Utilizing a Box-Behnken Design (BBD), interactive effects of current density, pH, and sulfate ion concentration (SO42-) were comprehensively analyzed, pinpointing the optimal reaction conditions: a current density of 0.56 A/cm(2), a pH of 8, and a SO42- concentration of 14 mmol/L, resulting in a COD degradation efficiency of 97.7 %. The influence of the factors on the COD removal rate decreases in the following order: current density > pH > SO42- concentration. In summary, this study proposed a practical strategy for leveraging ECO for COD degradation in coking wastewater which can be generated in the coal chemical industry.