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

Abstract

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 (H2O2). To conquer these disadvantages, an efficient visible-light-driven photo-Fenton system which can in-situ produce and apply H2O2 was investigated and developed, based on self-assembled CdS nanorods capable of converting dissolved O2 to H2O2. 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/Fe2+ 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 O2 to H2O2 via a direct two-electron reduction route but also accelerate the conversion of Fe3+ to Fe2+. 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.