Catalytic degradation of carbamazepine by a novel granular visible-light-driven photocatalyst activating the peroxydisulfate system

Powder activators are difficult to recycle in the peroxydisulfate (PDS) activation process, increasing the secondary pollution risk. In contrast, granular activators facilitate recycling, but with a weak PDS activation capability. Aiming at these limitations, a granular visible-light-driven photocatalyst (MoS2/rGO/WO3, MRW) with a diameter of 2.5 mm was synthesized. In the presence of 0.125 mM PDS and 2.5 g L-1 granular MRW, 79.67% carbamazepine was removed within 20 mM under visible-light irradiation, exhibiting a rapid degradation capability. The degradation efficiency was maintained at 70% during the cycling experiment, exhibiting a good stability of the granular MRW. Only 20 mu g L-1 tungsten was detected in the solution after a 10-hour dissolved-release experiment, demonstrating a low risk for secondary pollution. The cooperative catalytic degradation was mainly attributed to (OH)-O-center dot and SO4 center dot- . Eleven intermediates were identified and the corresponding degradation pathways were proposed. The good degradation performance of granular MRW makes it a promising wastewater treatment technology for future use.

Automated summary

The synthesized granular MRW photocatalyst showed high degradation efficiency and good stability in degrading carbamazepine under visible-light irradiation, with low risk of secondary pollution. It exhibited promising recycling capability and potential for future wastewater treatment applications.