Carbamazepine degradation by visible-light-driven photocatalyst Ag₃PO₄/GO: Mechanism and pathway

Carbamazepine (CBZ), as one of the most frequently detected pharmaceuticals, is of great concern due to its potential impact on the ecosystem and human health. This study provides an effective approach to remove CBZ by using photocatalyst silver phosphate combined with graphene oxide (Ag₃PO₄/GO) under visible irradiation. The morphology, composition, and optical properties of Ag₃PO₄/GO were characterized employing SEM, XRD, and DRS. Graphene oxide could improve the visible-light utilization and promote electron's charge to enhance the photocatalytic performance of Ag₃PO₄/GO. With the optimal reaction condition of 5.86 mW/cm² light intensity, 15–25 °C temperature, 5–7 pH, and 0.5 mg/L catalytic dosages, 5 mg/L CBZ could be completely degraded in 30 min, and the apparent rate constant could reach 0.12 min⁻¹. Additionally, the radical trapping experiments indicated •OH and O₂ˉ• were the main reactive oxygen species employed to eliminate CBZ. The decay pathways of CBZ had been proposed accordingly, and the main product was the low-molecular products.