Degradation of Diclofenac in Water Using S2O82−/Fe2O3-zeolite Catalyst Synergistic with Ozone

A number of water pollution issues caused by antibiotic effluent must be addressed immediately. The persulfate (PS) method is a sort of advanced oxidation process that has the advantages of a quick reaction time and a high oxidation capacity. However, in order to be used efficiently for wastewater treatment, PS must be activated in water. In this study, PS was directly loaded onto the precursor to produce an oxidant that could destroy organic contaminants in water synergistically with O₃. The effects of oxidant production circumstances, oxidant dosage, O₃ flow rate, PS dose, and pH value on diclofenac (DCF) degradation efficiency were investigated. The results showed that when the initial concentration of DCF was 100 mg/L, the O₃ flow rate was 0.4 m³/h, the pH value was 3, and the oxidant dosage was 1 g/L, the S₂O₈²⁻/Fe₂O₃-zeolite/O₃ system basically completely degraded DCF within 60 min. The EPR and free radical quenching experiments were used to explore the synergistic degradation of DCF by the S₂O₈²⁻/Fe₂O₃-zeolite/O₃ system. The three possible degradation pathways of DCF were also proposed based on analysis intermediate products analysis with LC–MS. This study identifies potential DCF breakdown pathways and offers a cost-effective and practical multiphase catalyst for the treatment of organic wastewater.

Graphical Abstract

A new sulfur-containing catalyst produces both ^•OH and SO₄^•− under the action of ozone for efficient removal of diclofenac.