Peroxymonosulfate activation by cobalt-doped ferromanganese magnetic oxides through singlet oxygen and radical pathways for efficient sulfadiazine degradation

Abstract

In this paper, cobalt-doped MnFe₂O₄ (CMFO-0.4) with oxygen vacancies was successfully synthesised by the sol–gel method and applied as a high-performance catalyst for the activation of peroxomonosulfate (PMS). The catalyst showed an excellent catalytic effect for the degradation of sulfadiazine (SDZ) by activated PMS, and the degradation rate can reach 100% in 10 minutes. The effects of different conditions on the degradation of SDZ were investigated, and it was determined that the optimal concentrations of catalyst and PMS were 0.2 g L⁻¹ and 1 mM, respectively, and had good degradation effects in the pH 5–11 range. Free radical quenching experiments, XPS, and electron paramagnetic resonance (EPR) analyses revealed the presence of hydroxyl radicals (˙OH), sulphate radicals (SO₄˙⁻), singlet oxygen (¹O₂), and superoxide radicals (˙O₂⁻) in the CMFO-0.4/PMS system, with ¹O₂ being the main reactive oxygen species (ROS). In addition, CMFO-0.4 has good reusability and adaptability to the presence of other substances.