A comparison of the degradation of benzothiazole in the UV/H₂O₂ and UV/K_2s2o8 systems: degradation processes and degradation mechanisms

The increasing presence of benzothiazole (BTH) in industrial wastewater poses significant environmental and health risks due to its persistence and toxicity. This study compares UV/persulfate (UV/K₂S₂O₈) and UV/H₂O₂ systems for benzothiazole (BTH) degradation, revealing that UV/K₂S₂O₈ achieves complete BTH removal (100%, 0.189 min⁻¹) versus 85% (0.092 min⁻¹) for UV/H₂O₂ under identical conditions. Radical scavenging experiments and LC-MS analysis demonstrate sulfate radicals outperform hydroxyl radicals in oxidizing BTH heterocyclic structure, reducing intermediates by 63% (quantified via peak area ratios). pH-dependent kinetics show UV/K₂S₂O₈ maintains efficacy (90–100% removal) across pH 3–9, while UV/H₂O₂ efficiency drops to 58% at pH > 7. Practical validation in river water confirms UV/K₂S₂O₈ robustness (98% BTH degradation), positioning it as a scalable, energy-efficient solution for refractory pollutant treatment. The results showed that the oxidant concentration and pH affected the degradation rate of BTH by changing the free radical concentration, and the UV/ K₂S₂O₈ was demonstrated to be able to achieve efficient removal of pollutants in complex environmental matrices. Free radical scavenging experiments and liquid chromatography-mass spectrometry analysis confirm that sulfate radicals are more effective than hydroxyl radicals in oxidizing and degrading BTH, enabling rapid, efficient, and environmentally friendly degradation of pollutants. This is mainly due to the higher redox potential of sulfate radicals (2.8–3.1V) compared to hydroxyl radicals (2.01V), resulting in the generation of fewer intermediates. Compared to UV/H₂O₂, UV/K₂S₂O₈ is a more effective, cleaner, and energy-saving method for pollutant removal in various complex environmental matrices.