Efficient removal of estradiol using MnFeO microsphere and potassium persulfate complex salt.

In this study, MnFeO microspheres were synthesized to activate potassium persulfate complex salt (Oxone) for the degradation of 17β-estradiol (17β-E2) in aqueous solutions. The characteristic of MnFeO 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, MnFeO 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 SO• and •OH participated in the reaction process of the whole reaction system, with SO• being the main reactive oxygen species (ROS). The activation mechanism of the MnFeO/Oxone/17β-E2 system is proposed as follows: MnFeO initially reacts with O and HO in solution to generate active Fe-OH and Mn-OH species. Subsequently, Fe-OH and Mn-OH react with Oxone in a heterogeneous phase activation process, producing highly reactive free radicals. After four cycles of MnFeO material, the removal rate of 17β-E2 decreased by 24.1%.