Comparison of EB-radiolysis and UV/H₂O₂-degradation of CBZ in pure water and solutions

It was learned that 99% degradation rate of carbamazepine (CBZ) (75 mg/L) in solutions was got under 10 kGy by EB (electron beam) irradiation while 15.74% and 96.02% CBZ (2 mg/L) degradation rate was got by UV and UV/H₂O₂ process in 180 min. EB-radiolysis was thought to be an efficient and energy-saving method to decompose CBZ in comparison of energy consumption between EB irradiation and UV/H₂O₂. Alkali metal cations which existed in surface water have little inhibition on the degradation of CBZ under EB and UV/H₂O₂ process. The anions usually existed in surface water had little suppression on EB-radiolysis of CBZ, while have an inhibition on UV-photodegradation of CBZ. Fe³⁺ promoted the degradation under EB irradiation and UV (ultraviolet) irradiation because of being the OH promoter. In addition, Fe²⁺ hugely enhanced the degradation of CBZ under UV irradiation. On the basis of the intermediates' appearance during the radiolysis, the main degradation pathway for the mineralization of CBZ was proposed under EB irradiation. It came to a conclusion that EB-radiolysis was an efficient and energy-saving method to completely mineralize CBZ. (authors)