Degradation of 2,4,6-trichlorophenol using magnetic nanoscaled Fe3O4/CeO2 composite as a heterogeneous Fenton-like catalyst

• Magnetic nanoscaled Fe3O4/CeO2 composite was used to degrade TCP.
• OH mechanism was determined to predominate in the process.
• A possible degradation pathway of TCP was proposed.

The degradation of 2,4,6-trichlorophenol (TCP) was investigated by using magnetic nanoscaled Fe3O4/CeO2 composite as a heterogeneous Fenton-like catalyst. The individual and interactive effects of four process variables, i.e. solution pH, initial TCP concentration, Fe3O4/CeO2 dosage and H2O2 concentration, on TCP removal, mineralization and dechlorination were investigated by response surface methodology (RSM) using the central composite design (CCD). The optimal regions of degradative conditions were pH 2.0–2.1, TCP 20–100 mg/L, Fe3O4/CeO2 1.5–2.5 g/L, and H2O2 17–30 mM. The removal efficiency, mineralization and dechlorination rate of TCP was 99%, 65% and 95% after 90 min, respectively under the conditions of pH 2.0, TCP 100 mg/L, Fe3O4/CeO2 2.5 g/L and H2O2 30 mM, which agreed well with the modeling prediction. Fe3O4/CeO2 showed a high catalytic ability for the removal of TCP in comparison with other processes. The recyclability of Fe3O4/CeO2 was also examined. According to the results of iron leaching, the effects of radical scavengers and intermediates determination, a possible pathway of TCP degradation was proposed based on OH mechanism (including free OH in the bulk liquid and surface-bounded OH).