Decomposition of 2-mercaptothiazoline in an aqueous solution by ozonation with UV radiation

This study investigates the enhanced ozonation of 2-mercaptothiazoline (2-MT), which is a pollutant of concern in the water environments, with ultraviolet (UV) radiation. Semibatch ozonation experiments are proceeded under various reaction conditions to examine the effects of ozone dosage and UV radiation on the decomposition of 2-MT. The enhancement of UV radiation on the ozonation of 2-MT is significant for overcoming the reaction resistance of the heterocyclic structure of 2-MT, which exhibits high resistance to the attack of ozone alone according to our previous study, indicating a low mineralization extent. The nearly complete mineralization of 2-MT via O-3/UV photolysis can be achieved, accompanied with the generation of sulfate, ammonium, and nitrate ions. Furthermore, distinct relationships between the formation of ions and the mineralization extent of 2-MT during O-3/UV photolysis are obtained. In addition, ozone consumption per mole of 2-MT, which increases significantly with the intensity of UV radiation, shows a high correlation with the treatment qualities of O-3/UV photolysis of 2-MT. The results reveal that O-3/UV photolysis is more feasible than pure ozonation and provide useful information for the proper application of an ozonation system for the removal of 2-MT.