Comparison of electron beam (EB) irradiation, EB/H2O2, EB/ peroxymonosulfate for quinoline degradation in aqueous solution: Degradation performance, intermediates and toxicity assessment

EB–oxidant systems greatly enhanced quinoline removal and mineralization. • Oxidant coupling redirected degradation from bi-aromatics to rapid ring-cleavage. • EB/PMS enabled fastest detoxification; EB/H₂O₂ ensured deepest oxidation. In present work, the degradation of quinoline, the intermediates produced and their toxicity were evaluated using electron beam (EB) irradiation and its coupling with oxidants (H 2 O 2 and peroxymonosulfate) processes. Under the conditions of an initial quinoline concentration of 50 mg/L and pH= 9, a complete removal of 100% and 40% mineralization was achieved at an absorbed dose of 5 kGy. EB irradiation efficiently decomposes quinoline, with ·OH identified as the dominant reactive species. However, high initial substrate concentration, low pH, and elevated salinity reduced mineralization efficiency by promoting radical scavenging. Coupling oxidants significantly enhances system performance. EB/H 2 O 2 amplified ·OH generation, achieving the highest TOC removal, while EB/PMS rapidly removed quinoline even in coking wastewater, demonstrating strong resistance to complex matrices. EB alone generated multiple bi-aromatic intermediates, limiting mineralization. EB/H 2 O 2 redirected degradation toward the C9 pathway, producing fewer intermediates and facilitating deep oxidation. EB/PMS accelerated ring-cleavage, preferentially forming mono-aromatic end-products. Toxicity evaluation showed that intermediates formed under EB alone were more toxic than quinoline. EB/PMS achieved the fastest detoxification and EB/H 2 O 2 achieved the highest mineralization. This work provides new mechanistic insights into EB-based advanced oxidation and supports its application in real industrial wastewater treatment. Download: Download high-res image (146KB) Download: Download full-size image