Degradation of carbamazepine by combined radiation and persulfate oxidation process

In this study, the degradation of carbamazepine (CBZ) was studied in the presence of persulfate (PS) at various initial pH values (6.5, 7.5, 8.5) and PS dosages (0.5, 1.0, 1.5, 2.0 mM). The experimental results showed that although gamma radiation alone could efficiently degrade CBZ, the combined radiation with PS oxidation could enhance the degradation and mineralization of CBZ. Acidic condition (pH = 6.5) could facilitate PS-oxidization process, when the concentration of PS was 1.5 mM, the mineralization efficiency (34.1% TOC removal) was highest at the absorbed dose of 1.0 kGy. Three carboxylic acids and seven intermediate products were detected during CBZ degradation process by the combined radiation/PS process. Based on the identified intermediate products, the possible mechanism and pathway of CBZ degradation were tentatively proposed. It was found that the biodegradability of CBZ was promoted with the combinative processes of gamma irradiation and PS.