Effective removal of antibiotics from water by Cu₂O/Co₃O₄-catalyzed peroxymonosulfate oxidation: catalytic performance and degradation mechanism

The development of efficient peroxymonosulfate (PMS) activated catalysts is important for the degradation and mineralization of organic pollutants. Metal-organic frameworks derived cobalt oxide modified cuprous oxide (Cu₂O/Co₃O₄) with carbon bone were constructed by driving a dual-precursors of zeolitic imidazolate framework (ZIF-67) and Cu₂O, activating PMS for organic degradation. XRD, FT-IR, EDS analyses and XPS were used to demonstrate phase purity while SEM and HR-TEM were used to discover the shape of the synthesised material. EIS, transient current and LSV were used to enquire about the conductivity of the samples and change in current density accordingly. The degradation efficiency of Cu₂O/Co₃O₄-10 for TC reached 89.8% within 60 min under dark conditions. Its activated degradation of oxytetracycline (OTC), levofloxacin (LEV) and ciprofloxacin (CIP) was 89.4%, 81.32% and 54.09%, respectively. Spherical cuprous oxide loaded on cubic cobalt oxide. Furthermore, the effective activation of PMS was achieved by increasing the electron donor capacity of Co and redox cycling of Cu. The single linear state of oxygen (¹O₂) produced by Cu₂O/Co₃O₄ is well adapted to H₂PO₄⁻ and is active at pH = 7. Notably, Cu₂O/Co₃O₄ utilized hydrogen persulfate (HSO₅⁻) to generate superoxide radicals (·O₂⁻) and ¹O₂ in the PMS system by Co³⁺/Co²⁺ and Cu²⁺/Cu⁺ cyclic conversion. The strong interaction and electron transfer between Cu₂O/Co₃O₄ and PMS and the synergistic effect of the bimetallic oxide redox cycle accelerated improved the catalytic activity. In conclusion, this study provides a new perspective that is conducive to improving the practical application of sulfate radical-based advanced oxidation processes (SR-AOPs).