Peroxymonosulfate oxidation of carbamazepine by Iron-Biochar via nonradical pathways: Singlet oxygen, electron transfer, and Fe (IV)

In this study, the synthesis of Fe@BC (biochar) was successfully achieved using a one-step calcination process. The catalyst exhibited notable pore structures, a considerable specific surface area, and surface functional groups. Heterogeneous catalytic experiments further demonstrated that the CBZ degradation was significantly improved in the Fe2@BC900℃-PMS process, in comparison to alternative catalytic processes. The quenching, ESR analyses, and electrochemical tests (CV, LSV, OCP, and EIS) provided evidence that the CBZ degradation occurred via nonradical pathways involving the participation of 1O2, electron transfer, and Fe (IV). Furthermore, the potential mechanisms of PMS activation in the Fe2@BC900℃-PMS process were systematically elucidated. DFT, LC-MASS tests and ECOSAR suggested that CBZ can be transformed into smaller, less toxic molecules during the treatment. Moreover, the cyclic experiments revealed that the Fe2@BC900℃-PMS process maintained a consistent oxidation capacity for CBZ even after undergoing ten cycles. Based on the above findings, it can be concluded that the Fe2@BC900℃-PMS process could effectively degrade organic pollutants in water.