Efficient removal of estradiol using MnFe2O4 microsphere and potassium persulfate complex salt

Abstract

Abstract In this study, MnFe2O4 microspheres were synthesized to activate potassium persulfate complex salt (Oxone) for the degradation of 17β-estradiol (17β-E2) in aqueous solutions. The characteristic of MnFe2O4 was detected by XRD, XPS and SEM-EDS. The experimental results indicated that the degradation of 17β-E2 followed pseudo-first-order kinetics. At 25 °C, 17β-E2 concentration of 0.5 mg/L, MnFe2O4 dosage of 100 mg/L, Oxone dosage of 0.5 mmol/L, and initial pH value of 6.5, the decomposition efficiency of 17β-E2 reached 82.9% after 30 min of reaction. Additionally, free radical quenching experiments and electron paramagnetic resonance analysis demonstrated that SO4 −• and •OH participated in the reaction process of the whole reaction system, with SO4 −• being the main reactive oxygen species (ROS). The activation mechanism of the MnFe2O4/Oxone/17β-E2 system is proposed as follows: MnFe2O4 initially reacts with O2 and H2O in solution to generate active Fe3+-OH and Mn2+-OH species. Subsequently, Fe3+-OH and Mn2+-OH react with Oxone in a heterogeneous phase activation process, producing highly reactive free radicals. After four cycles of MnFe2O4 material, the removal rate of 17β-E2 decreased by 24.1%.

Keywords

• Sulfate radical
• Heterogeneous activation
• Oxygen species
• Activation mechanism