Enhanced degradation of sulfamethoxazole by Fe–Mn binary oxide synergetic mediated radical reactions

• Published in: Environmental science and pollution research international 2019-05, Vol.26 (14), p.14350-14361
• Main Authors: Wu, Kang, Si, Xiongyuan, Jiang, Jin, Si, Youbin, Sun, Kai, Yousaf, Amina
• Format: Article
• Language: English
• Subjects: Antibiotics; Aquatic environment; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Degradation; Earth and Environmental Science; Ecotoxicology; Electron paramagnetic resonance; Environment; Environmental Chemistry; Environmental Health; Environmental science; Free radicals; Hospital wastes; Hydrogen peroxide; Iron; Liquid chromatography; Manganese; Manganese oxides; Mass spectrometry; Mass spectroscopy; Medical wastes; Mineralization; Oxidation; Oxides; Oxidizing agents; pH effects; Radicals; Reaction products; Research Article; Sulfamethoxazole; Waste Water Technology; Wastewater; Wastewater treatment; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-019-04710-4

In this study, a novel Fe–Mn binary oxide (FMBO), which combined the oxidation capability of iron and manganese oxides, was constructed to remove sulfamethoxazole (SMX) effectively using the simultaneous co-precipitation and oxidation methods, and the reaction products were probed by liquid chromatography-mass spectrometry (LC/MS). Particularly, FMBO-mediated transformation mechanisms of SMX were explored using radical scavengers and electron paramagnetic resonance (EPR). Results indicated that the best removal efficiency was obtained at a pH of 4.0, with the H 2 O 2 of 6.0 mmol/L and the FMBO dosage of 2.0 g/L, giving 97.6% removal of 10 mg/L SMX within 60 min. More importantly, we found that the hydroxyl (•OH) radicals generated by FMBO through Fenton-like reaction were responsible for the SMX oxidation. EPR studies were confirmed that the peak intensities of hydroxyl adduct decreased remarkably with increasing pH values. Moreover, the four SMX degradation intermediate products were detected by LC/MS and a reaction pathway for the possible mineralization of SMX, with •OH radicals as the main oxidant, was proposed. These findings provide a novel insight into the removal of SMX by FMBO-mediated radical reactions in aquatic environments. Moreover, this research suggested that FMBO can act as an efficient catalyst to remove SMX in hospital wastewater.