Microwave-assisted electro-peroxone process for rapid removal of high-concentration recalcitrant dye solutions

Azo dyes are persistent pollutants commonly found in industrial wastewaters. This study evaluated the microwave-electro-peroxone (MW-EP) process for degradation of Reactive Yellow 84 (RY84) and optimized the operating conditions, using the one-factor-at-a-time (OFAT) approach. The optimum conditions were an initial dye concentration of 300 mg/L, pH 6.5, current intensity of 400 mA, microwave power of 279 W, ozone flow rate of 0.288 g/h, and NaCl concentration of 0.035 M. Under these conditions, 91.36% dye removal was achieved within 17 min, with an energy consumption of 579.25 kWh/kg. Chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies reached 75.3% and 55.8%, respectively. Scavenger experiments identified ȮH and ¹O₂ as the main reactive species, while a synergy index of 1.91 indicated a constructive interaction between MW irradiation and EP oxidation. The degradation followed first-order kinetics. These findings highlight the applicability of the MW-EP process for treating high-concentration dye-containing wastewater.