The performance and pathway of benzothiazole degradation by electron beam irradiation

Benzothiazole (BTH) is a typical refractory heterocyclic compound that can be used as a photosensitive material in organic synthesis and conditional plant resource research. The extensive use of BTH has led to high BTH concentrations in natural environment, such as in tap water and urine, which tend to inhibit animal hormone synthesis and induce genotoxicity. Traditional wastewater treatment processes cannot effectively remove BTH. Therefore, we aimed to use the electron beam method, an emerging method for pollutant degradation, to degrade BTH in water. Experiments showed that BTH can be effectively degraded (up to 90%) when the electron beam reaches 5 kGy and irradiation conformed perfectly to the pseudo first-order kinetics model. Experimental results showed that acidic conditions are more favorable for electron beam degradation of BTH, while the degradation of most other inorganic ions is inhibited (except SO42−). Hydroxyl radicals (•OH) was confirmed to play a major role in degradation by the experiment, and the mineralization rate was greatly increased by the addition of H2O2 and K2S2O8. In addition, our experimental and theoretical calculations showed that the degradation of BTH occurred mainly through the opening of the benzene ring. Theoretical calculations showed that the toxicity of BTH decreased significantly after electron beam degradation, making it an effective way to degrade BTH. [Display omitted] •Electron beam irradiation effectively removed benzothiazole.•By analyzing the contributing factors of benzothiazole EB treatment, its degradation mechanism is clarified.•Benzothiazole degradation pathways are proposed.•The toxicity of benzothiazole is significantly reduced after irradiation treatment.