title: Degradation of fluoroquinolone antibiotics by ferrate(VI): Effects of water constituents and oxidized products.
abstract: The degradation of five fluoroquinolone (FQ) antibiotics (flumequine (FLU), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL) and marbofloxacin (MAR)) by ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) was examined to demonstrate the potential of this iron-based chemical oxidant to treat antibiotics in water. Experiments were conducted at different molar ratios of Fe(VI) to FQs at pH 7.0. All FQs, except FLU, were degraded within 2 min at [Fe(VI)]:[FQ] ≤ 20.0. Multiple additions of Fe(VI) improved the degradation efficiency, and provided greater degradation than a single addition of Fe(VI). The effects of anions, cations, and humic acid (HA), usually present in source waters and wastewaters, on the removal of FLU were investigated. Anions (Cl(-), SO4(2-), NO3(-), and HCO3(-)) and monovalent cations (Na(+) and K(+)) had no influence on the removal of FLU. However, multivalent cations (Ca(2+), Mg(2+), Cu(2+), and Fe(3+)) in water decreased the efficiency of FLU removal by Fe(VI). An increase in the ionic strength of the solution, and the presence of HA in the water, also decreased the percentage of FLU removed by Fe(VI). Experiments on the removal of selected FQs, present as co-existing antibiotics in pure water, river water, synthetic water and wastewater, were also conducted to demonstrate the practical application of Fe(VI) to remove the antibiotics during water treatment. The seventeen oxidized products (OPs) of FLU were identified using solid phase extraction-liquid chromatography-high-resolution mass spectrometry. The reaction pathways are proposed, and are theoretically confirmed by molecular orbital calculations.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
authors.forename: Mingbao
authors.initials: M
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
authors.forename: Xinghao
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
authors.forename: Ruijuan
authors.initials: R
authors.lastname: Qu
authors.affiliation: Centre of Modern Analysis, Nanjing University, Nanjing, Jiangsu 210093, PR China.
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Sui
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Cizmas
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China. Electronic address: wangzy@nju.edu.cn.
authors.forename: Zunyao
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, College Station, TX 77843, USA. Electronic address: vsharma@sph.tamhsc.edu.
authors.forename: Virender K
authors.initials: VK
authors.lastname: Sharma
mesh_terms: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D014867:Water; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D014874:Water Pollutants, Chemical; D014867:Water; D007501:Iron
keywords: Antimicrobials; Ferrate(VI); Humic acid; Ions; Quantum chemical calculations; Water treatment