Integrated electrocoagulation and sulfate radical-based AOP for real waste coolant treatment

Abstract

Waste coolant, distinguished by its elevated chemical oxygen demand (COD) and total suspended solids (TSS), poses considerable environmental hazards. Nevertheless, effective treatment methods are imperative for addressing these concerns. The present study investigates the use of integrated electrocoagulation and sulfate radical-based advanced oxidation processes (EC/PS) with aluminium electrodes and persulfate (PS) for the remediation of coolant waste in a real-world context. The synergistic indexes of 16.96 for TSS and 23.99 for COD indicate that PS significantly enhanced the EC process oxidation capacity. The removal of TSS was accomplished through aluminium ion coagulation, whereas the removal of COD was achieved through a combination of oxidation and floc enmeshment. The enhancement of current density from 65 to 190 mA/cm2 within a 20-minute reaction time led to a substantial improvement in TSS removal, increasing from 62.21 f 2.49 to 89.74 f 0.05 . A similar trend was observed in COD removal, which increased from 60.35 f 2.41 to 82.78 f 3.31 . These findings suggest that the EC/PS process has the potential to serve as an effective treatment for high-strength waste coolant, particularly under optimal conditions characterized by low pH and high PS dosage.