Catalytic Degradation of Rhodamine B by FeOCl Activated Hydrogen Peroxide

Abstract

The wide application of traditional Fenton reactions was firmly restricted by the requirement for harsh acid conditions, as well as the inevitable generation of iron slurry. The FeOCl nanosheets, prepared by the chemical vapor transformation method, were used to degrade RhB via activation of H2O2. The FeOCl was characterized by a field emission scanning electron microscope (FE-SEM) and X-Ray Diffractometer (XRD), the results showed that FeOCl exhibited a fine crystal structure and nanosheet-like morphology, which was favorable for exposure of active sites. The results of degradation experiments showed that the RhB was totally removed within 15 min under the conditions of[H2O2]=1.67 mmol·L-1 and[FeOCl]=200 mg·L-1. The initial pH plays a negative role in RhB degradation, and the initial pH increased from 3 to 7 as the RhB removal efficiency decreased from 100% to 84%. Typically, when the initial pH was 9, the RhB degradation sharply decreased to 57.6%. Compared with traditional Fenton reactions, the FeOCl/H2O2 system widened the pH range, which resulted in superior organics removal even under a mild-acidic to medium pH condition. The quenching experiments demonstrated that the·OH was the major reactive oxygen species. Additionally, Electron Paramagnetic Resonance (EPR) results showed that intense DMPO-HO·signals were detected in the FeOCl/H2O2 system, which further demonstrated the important role of·OH in RhB degradation.