Photo-Fenton degradation of sulfamethazine using self-assembled CdS nanorods with in-situ production of H2O2 at wide pH range

• Self-assembled CdS nanorods were synthesized and used as photo-Fenton catalyst. • CdS nanorods had excellent catalytic performance and stability. • CdS/Fe 2+ photo-Fenton system can degrade various pollutants at wide pH range. The large-scale application of the conventional Fenton process is restricted by the strict acidic working pH and the demand for externally supplying hydrogen peroxide (H 2 O 2 ). To conquer these disadvantages, an efficient visible-light-driven photo-Fenton system which can in-situ produce and apply H 2 O 2 was investigated and developed, based on self-assembled CdS nanorods capable of converting dissolved O 2 to H 2 O 2 . The self-assembled CdS nanorods had high purity and good crystallinity with a pine-leaf-like structure. Highly effective degradation of sulfamethazine (SMT) was achieved by the CdS/Fe 2+ photo-Fenton system under visible light irradiation and 20 mg/L SMT was almost completely degraded within 90 min over a broad pH range from 4 to 8. It was attributed that self-assembled CdS nanorods with excellent photocatalytic activity could produce numerous photoelectrons, which could not only reduce dissolved O 2 to H 2 O 2 via a direct two-electron reduction route but also accelerate the conversion of Fe 3+ to Fe 2+ . Moreover, the self-assembled CdS nanorods possessed excellent reusability and the constructed photo-Fenton system exhibited widespread suitability for degradation of different pollutants, demonstrating potential applications in wastewater treatment. It is expected that this study can provide new ideas for improving the conventional Fenton process.