Degradation of carbamazepine by radiation-induced activation of peroxymonosulfate

In this study, the radiation-induced activation of peroxymonosulfate (PMS) was investigated for the degradation of carbamazepine (CBZ), and compared with single PMS system, single radiation system and Fe(II)-activated PMS system. The results showed that gamma radiation can effectively activate PMS, and the presence of PMS could decrease the absorbed dose required to completely degrade CBZ. Moreover, the removal efficiency of TOC was 38.3% in the gamma radiation-induced activation of PMS system, which was higher than that in the single PMS system, single radiation system and the Fe(II)-activated PMS system. Hydroxyl radicals played major role in the degradation of CBZ. However, the contribution of hydroxyl radicals for the CBZ degradation decreased as the absorbed dose increased from 100 Gy to 800 Gy. In addition, the sulfate radical and persulfate formed during the radiation/PMS process also contributed to CBZ degradation. The maximum decomposition efficiency was found with the molar ratio of PMS to CBZ of 20:1 at adsorbed dose of 300 Gy. Furthermore, the intermediate products were identified, and the degradation pathway of CBZ was tentatively proposed. In summary, the gamma radiation-induced activation of PMS system could be a promising technology for the removal of recalcitrant organic pollutants.