Thiabendazole Removal from Water and Mineralization by Electron Beam Irradiation Combined with Hydrogen Peroxide

Thiabendazole (TBZ) is a fungicide widely used in agriculture and frequently detected in water bodies and effluents from greenhouse and food processing activities. In this study, the removal and mineralization of TBZ from water by electron beam irradiation, in the absence and presence of hydrogen peroxide (H2O2), were investigated. Synthetic aqueous solutions containing TBZ (10 mg L−1) were treated at absorbed doses of 2, 3, and 4 kGy, using different H2O2 concentrations (0, 5, 10, and 15 mM). The effectiveness of TBZ removal was evaluated by determining residual TBZ concentrations, while mineralization was assessed through changes in total organic carbon (TOC), sulfate, and nitrate concentrations, together with pH and electrical conductivity measurements. Under all investigated conditions, complete TBZ degradation was achieved, with final concentrations below the detection limit of the chromatographic method. However, mineralization was partial and strongly dependent on treatment conditions. The highest mineralization degree was obtained at 4 kGy and 15 mM H2O2, resulting in a TOC removal of 52.4% and sulfur and nitrogen mineralization ratios of 50.2% and 13.7%, respectively. These results demonstrate that electron beam irradiation is highly effective for TBZ degradation. At the same time, while oxidant-assisted conditions are required to enhance mineralization, this highlights the need to distinguish between pollutant removal and complete mineralization in water treatment processes.