Using SiO2-Supported MnO2@Fe2O3 Composite to Catalytically Decompose Waste Drilling Fluids Through Fenton-like Oxidation

Waste drilling fluids produced from oil extraction can cause serious harm to the ecological environment; thus, the treatment of waste drilling fluids is urgent and important to ensure the sustainability and development of the oil extraction. In this work, we used the Fenton-like reaction method to degrade waste drilling fluids with SiO₂-supported MnO₂@Fe₂O₃ composite material as a catalyst in the presence of H₂O₂. During the Fenton-like reaction process, the MnO₂@Fe₂O₃ interface exhibits exceptional activity by facilitating the production of ·OH species with high activity and strong oxidizing properties, which degrade the organic substances in the waste drilling fluids into smaller inorganic molecules, thereby reducing its COD value. Compared to the reaction only with H₂O₂, after reacting with sufficient SiO₂-supported MnO₂@Fe₂O₃ catalyst for 4 h at 60 °C in the presence of H₂O₂, the COD value of the waste drilling fluids is reduced by 36,495 mg L^-1, a decrease of more than 95%. This performance is significantly superior to that of the traditional Fenton reagent FeSO₄, which reduced the COD by 32,285 mg L^-1, a decrease of 84%. This work provides an important composite catalyst, which is practically useful for the treatment of waste drilling fluids.