Degradation of 3,4-dichlorobenzotrifluoride by the Fenton-like process using zirconia-coated magnetite magnetic nanoparticles as an effective heterogeneous catalyst.

In this study, zirconia-coated magnetite magnetic nanoparticles (ZrO2/Fe3O4 MNPs) were prepared, characterized, and used as an effective and reusable heterogeneous catalyst for 3,4-dichlorobenzotrifluoride (3,4-DCBTE) degradation. The catalytic potential of the Fe3O4/ZrO2-H2O2 system for the removal of 3,4-DCBTE was tested in comparison with several other systems, and the effects of various operating parameters, including initial solution pH, catalyst addition, H2O2 concentrations, and reaction temperature, were also evaluated with respect to the degradation efficiency of 3,4-DCBTE. Results showed that the Fe3O4/ZrO2 composite could effectively enhance the oxidation of 3,4-DCBTE by the Fenton-like process, and there might be a synergetic effect in the Fe3O4/ZrO2 composite. When the mass ratio of Fe3O4 and ZrO2 was 1:1, the Fe3O4/ZrO2 exhibited the best catalytic activity, and the catalyst-driven Fenton process achieved high removal of 3,4-DCBTE (98.5%) and total organic carbon (TOC) (52.7%) at the operating conditions: pH 3.0, catalyst 2.0 g/L, H2O2 30 mM, temperature 30 °C, and reaction time 1 h. Furthermore, five successive runs of the Fenton oxidation using the same Fe3O4/ZrO2 composite resulted in the steady removal of 3,4-DCBTE, further confirming the high stability of the catalyst. In addition, the possible catalytic mechanism and degradation pathways of 3,4-DCBTE were also investigated.