Rapid Degradation of Carbamazepine in Wastewater Using Dielectric Barrier Discharge-Assisted Fe³⁺/Sodium Sulfite Oxidation

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Abstract The discharge of medical and domestic wastewater has resulted in a steady increase in the levels of pharmaceutical pollutants in water bodies. In this study, we combine dielectric barrier discharge (DBD) technology with an Fe³⁺/sodium sulfite oxidation system to address the limitations associated with traditional water treatment technologies in removing carbamazepine, exploring the application efficacy and mechanisms of this approach in carbamazepine degradation. Under optimized experimental conditions (0.5 mM Fe³⁺; 5 mM sodium sulfite; 90 W DBD discharge power), this system achieved a 97% degradation rate for carbamazepine within 4 min, significantly outperforming both DBD and sodium sulfite standalone systems. Using response surface methodology to optimize experimental parameters, the effects of sodium sulfite concentration, pH, and Fe³⁺ concentration on degradation efficiency were assessed. The system's degradation rate under optimal conditions was 2.5 times higher than that of individual systems. Hydroxyl and sulfate radicals contributed 65% and 85%, respectively, to carbamazepine degradation, while superoxide radicals contributed only 30%. This system was found to effectively break down carbamazepine's molecular structure. The main degradation products were 10,11-dihydro-10,11-dihydroxy-carbamazepine and benzoic acid. The concentrations of these products gradually decreased as degradation progressed, ultimately resulting in over 85% mineralization, confirming the complete degradation of carbamazepine. This study not only provides an effective technical solution for rapidly treating recalcitrant organic pollutants in water but also offers new insights for environmental protection and the sustainable use of water resources while providing theoretical and experimental data for future related research.