Efficient degradation of tetracycline by H2O2 catalyzed by FeOCl: A wide range of pH values from 3 to 7

Iron Oxychloride (FeOCl) was prepared by partial thermal decomposition and was studied as a heterogeneous Fenton catalyst to degrade tetracycline (TC). SEM, XRD, XPS technology were used to characterize its performance. The influencing factors of TC degradation efficiency were studied, including pH value, H2O2 content, catalyst dosage and initial TC concentration. The results showed that under the optimal conditions, the degradation rate of 60 mg L-1 TC reached 92.9% within 60 min of reaction. The degradation process follows a second order kinetic equation. Compared with other iron-based catalysts, FeOCl exhibited better catalytic and degradation effects. Moreover, FeOCl/H2O2 system exhibited a wide pH range (from 3.0 to 7.0) for efficient degradation of TC and showed excellent stability and reusability. Meanwhile, based on the intermediates identified by HPLC-MS, two possible pathways for the degradation of TC were proposed. Further, the results of electron spin resonance spectroscopy and radical quenching tests suggested that the center dot OH formed in the FeOCl/H2O2 system was mainly responsible for the degradation of TC.