Enhanced degradation of metronidazole by heterogeneous sono-Fenton reaction coupled ultrasound using Fe3O4 magnetic nanoparticles

Metronidazole (MNZ), one of the most commonly used nitroimidazole antibiotics in the world, poses a serious threat to human life and health. In this study, an enhanced sono-Fenton process for the degradation of MNZ is presented. The catalytic capacity of nano-Fe3O4 in systems comprising ultrasound + Fe3O4 + H2O2, and the influential parameters such as H2O2, nano-Fe3O4 doses and pH for the Sono-Fenton process, was investigated. The results showed that the nano-Fe3O4 particles appeared to be roughly spherical in shape, with an average size of 10–20 nm. It was found that •OH radicals were rapidly generated due to the catalytic activity of the nano-Fe3O4. MNZ could be degraded within a wide pH range, from 3 to 9, and the degradation efficiencies were considerably enhanced by ultrasound. When the MNZ concentration was fixed at 20 mg/L, the nano-Fe3O4 dosage at 500 mg/L, the pH at 3 and the reaction temperature at 30°C, the removal efficiencies of MNZ were above 98% after 5 h. It is indicated that Fe3O4 magnetic nanoparticles were synthesized as heterogeneous catalysts to effectively degrade MNZ, and the observed stability and recyclability demonstrated that nano-Fe3O4 was promising for the treatment of wastewater contaminated with antibiotics.