Peroxymonosulfate Activation by Co-Doped Magnetic Mn3O4 for Degradation of Oxytetracycline in Water

doi:10.21203/rs.3.rs-946361/v1

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Research Article

Peroxymonosulfate Activation by Co-Doped Magnetic Mn₃O₄ for Degradation of Oxytetracycline in Water

https://doi.org/10.21203/rs.3.rs-946361/v1

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published 30 Jan, 2022

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Co-doped magnetic Mn₃O₄ was synthesized by the solvothermal method and adopted as an effective catalyst for the degradation of oxytetracycline (OTC) in water. Synergistic interactions between Co-Mn₃O₄ and Fe₃O₄ not only resulted in the enhanced catalytic activity through the activation of peroxymonosulfate (PMS) to degrade OTC, but also made Fe₃O₄/Co-Mn₃O₄easy to be separated and recovered from aqueous solution. 94.2% of OTC could be degraded within 60 min at an initial OTC concentration of 10 mg/L, catalyst dosage of 0.2 g/L and PMS concentration of 10 mM, the high efficiency of which was achieved in a wider pH range of 3.0-10.0. The free radical quenching experiments showed that O₂^•- radicals and ¹O₂ played the main role in the degradation process. Co³⁺, Co²⁺, Fe²⁺, Fe³⁺, Mn⁴⁺, Mn³⁺ and Mn²⁺ on Fe₃O₄/Co-Mn₃O₄ were identified as catalytic sites based on XPS analysis. Eventually, the intermediates of OTC degradation were examined and the possible decomposition pathways were proposed. The excellent catalytic performance of Fe₃O₄/Co-Mn₃O₄ not only came from the fact that the large specific surface area could provide abundant active sites for the activation of PMS, but also the charged redistribution among atoms to accelerate the reduction of metal ions. The high degradation efficiency of OTC in actual water samples indicated that Fe₃O₄/Co-Mn₃O₄ had good potential for practical application.