Oxidation of Antibacterial Molecules by Aqueous Ozone:  Moiety-Specific Reaction Kinetics and Application to Ozone-Based Wastewater Treatment

• Published in: Environmental science & technology Vol. 40; no. 6; pp. 1969 - 1977
• Main Authors: Dodd, Michael C, Buffle, Marc-Olivier, von Gunten, Urs
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.03.2006
• Subjects: Amikacin; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - metabolism; Applied sciences; Cities; Exact sciences and technology; Hydrogen-Ion Concentration; Hydroxyl Radical - chemistry; Kinetics; Other wastewaters; Oxidants, Photochemical - chemistry; Oxidation; Oxidation-Reduction; Ozone; Ozone - chemistry; Pollution; Waste Disposal, Fluid - methods; Wastewaters; Water treatment; Water treatment and pollution; Drug; Ozonization; Hydroxyl radicals; Urban waste water; Physicochemical purification; Oxidation; Chemical degradation; Antibacterial agent; Waste water purification; Free radical reaction; Chemical reaction kinetics; Organic compounds
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es051369x

Ozone and hydroxyl radical (•OH) reaction kinetics were measured for 14 antibacterial compounds from nine structural families, to determine whether municipal wastewater ozonation is likely to result in selective oxidation of these compounds' biochemically essential moieties. Each substrate is oxidized by ozone with an apparent second-order rate constant, > 1 × 103 M-1 s-1, at pH 7, with the exception of N(4)-acetylsulfamethoxazole ( is 2.5 × 102 M-1 s-1). values (pH 7) for macrolides, sulfamethoxazole, trimethoprim, tetracycline, vancomycin, and amikacin appear to correspond directly to oxidation of biochemically essential moieties. Initial reactions of ozone with N(4)-acetylsulfamethoxazole, fluoroquinolones, lincomycin, and β-lactams do not lead to appreciable oxidation of biochemically essential moieties. However, ozone oxidizes these moieties within fluoroquinolones and lincomycin via slower reactions. Measured values and second-order •OH rate constants, , were utilized to characterize pollutant losses during ozonation of secondary municipal wastewater effluent. These losses were dependent on , but independent of . Ozone doses ≥3 mg/L yielded ≥99% depletion of fast-reacting substrates ( > 5 × 104 M-1 s-1) at pH 7.7. Ten substrates reacted predominantly with ozone; only four were oxidized predominantly by •OH. These results indicate that many antibacterial compounds will be oxidized in wastewater via moiety-specific reactions with ozone.