Degradation of ibuprofen using ozone combined with peroxymonosulfate

Abstract

Ozone combined with peroxymonosulfate (O₃/PMS) for degradation of ibuprofen (IBP) was studied in this work. The oxidation capacity of O₃/PMS and four other related oxidation processes for IBP degradation was compared. O₃/PMS demonstrated a compelling degradation ability towards IBP compared with O₃, PMS, O₃/PDS, and O₃/H₂O₂ processes. The generation of ˙OH and SO₄˙⁻ in O₃/PMS was proved by electron spin resonance detection, and the dominant highly oxidative species was determined based on the different scavenging performances of tert-butanol and ethanol towards ˙OH and SO₄˙⁻. The affecting factors including O₃ and PMS dosage, initial pH, and organic and inorganic constituents in water were investigated. An optimum dosage of O₃ and PMS was observed for degradation of IBP in O₃/PMS. Though a notably synergistic effect was observed in O₃/PMS for IBP degradation under pH 3.0, 5.0, 7.6 and 9.0, alkaline conditions were found to be more beneficial for IBP degradation. Humic acid, which was used to simulate the natural organic water matrix, posed different effects on O₃ and O₃/PMS for IBP degradation. The presence of Cl⁻, which is a typical reductive inorganic ion and ubiquitous in natural water, inhibited O₃/PMS oxidation on the degradation of IBP. The degradation kinetics of IBP in O₃/PMS was also studied in this work.