Performance and mechanism of a synergistic system constructed by pulsed gas-liquid discharge plasma, CuFe₂O₄ and persulfate for high-efficiency antibiotic degradation

Plasma synergized Fenton-like catalysts are regarded as a highly promising method for antibiotic degradation. However, further enhancement is required in terms of the energy utilization efficiency of the plasma and the performance of the Fenton-like catalyst. In this study, a synergistic system of pulsed gas-liquid discharge (PGLD), heterogeneous Fenton-like catalyst CuFe₂O₄ (CFO), and persulfate (PS) is constructed for the efficient degradation of tetracycline. The degradation rate in the PGLD/CFO/PS system reached 96.9 % with a synergistic factor of 2.85 when 80 mg of CFO and 3 mM of PS were added. The initial solution pH, the dosage of CFO and PS, and the working gas can also exert a considerable influence on degradation. The higher concentrations of H₂O₂ and O₃ may account for the higher degradation rates observed in the PGLD/CFO/PS system. ESR experiments demonstrated that the PGLD/CFO/PS system was more conducive to [rad]OH and SO₄[rad]⁻ formation, which are the key active species for degradation. Three potential degradation pathways were postulated according to the degradation intermediates. The PGLD/CFO/PS system has been demonstrated to significantly reduce the toxicity of the antibiotic solution following treatment. This research provides a prospective approach for the sustainable implementation of wastewater treatment.