Sulfurized oolitic hematite as a heterogeneous Fenton-like catalyst for tetracycline antibiotic degradation

A sulfurized oolitic hematite (SOH-600) was prepared successfully via annealing oolitic hematite in hydrogen sulfide and was investigated as a heterogeneous Fenton catalyst for the degradation of tetracycline. The physicochemical properties of SOH-600 before and after reaction were characterized by XRF, XRD, XPS, SEM and FT-IR. The influence of the experimental parameters on the performance of SOH-600, including SOH-600 dosage, initial H2O2 concentration, and initial solution pH, was systematically investigated. The results showed that the degradation process of TC followed the second-order kinetic model and that the degradation efficiency increased along with increasing SOH-600 dosage, increasing initial H2O2 concentration, and decreasing initial solution pH under the experimental conditions. Moreover, SOH-600 exhibited an excellent recycling performance and a high catalytic efficiency (> 90%) after five cycles. UV vis, TOC, ESR, and HPLC-MS analyses were used to reveal that the (OH)-O-center dot formed in the SOH-600/H2O2 system was mainly responsible for the degradation of TC, and the degradation pathway of TC was proposed.