title: Electrochemical incineration of the antibiotic ciprofloxacin in sulfate medium and synthetic urine matrix.
abstract: The degradation of 100 mL of 0.245 mM of the antibiotic ciprofloxacin in 0.05 M Na2SO4 at pH 3.0 has been studied by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF). Electrolyses were performed with a stirred tank reactor using either a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode. In EF, PEF and SPEF, ciprofloxacin was rapidly removed due to its oxidation with (•)OH formed from Fenton's reaction between added Fe(2+) and H2O2 generated at the cathode. The larger electrochemical incineration of the antibiotic was achieved by SPEF with BDD with 95% mineralization thanks to the additional attack by hydroxyl radicals formed from water oxidation at the BDD anode surface and the photolysis of final Fe(III)-oxalate and Fe(III)-oxamate species from sunlight. Up to 10 primary intermediates and 11 hydroxylated derivatives were identified by LC-MS, allowing the proposal of a reaction sequence for ciprofloxacin mineralization. A different behavior was found when the same antibiotic concentration was oxidized in a synthetic urine matrix with high urea content and a mixture of PO4(3-), SO4(2-) and Cl(-) ions. Since Fenton's reaction was inhibited in this medium, only EO and EO-H2O2 processes were useful for mineralization, being the organics mainly degraded by HClO formed from Cl(-) oxidation. The EO process with a BDD/stainless steel cell was found to be the most powerful treatment for the urine solution, yielding 96% ciprofloxacin removal and 98% mineralization after 360 min of electrolysis at optimum values of pH 3.0 and current density of 66.6 mA cm(-2). The evolution of released inorganic ions was followed by ion chromatography.
authors.affiliation: Laboratório de Eletroquímica e Materiais Nanoestruturados (LEMN), Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC (UFABC), Rua Santa Adélia, 166, 09210-170 Santo André-SP, Brazil.
authors.forename: Vanessa S
authors.initials: VS
authors.lastname: Antonin
authors.affiliation: Laboratório de Eletroquímica e Materiais Nanoestruturados (LEMN), Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC (UFABC), Rua Santa Adélia, 166, 09210-170 Santo André-SP, Brazil. Electronic address: mauro.santos@ufabc.edu.br.
authors.forename: Mauro C
authors.initials: MC
authors.lastname: Santos
authors.affiliation: Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
authors.forename: Sergi
authors.initials: S
authors.lastname: Garcia-Segura
authors.affiliation: Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain. Electronic address: brillas@ub.edu.
authors.forename: Enric
authors.initials: E
authors.lastname: Brillas
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D002939:Ciprofloxacin / Q000737:chemistry*; D055664:Electrochemical Techniques; D017745:Incineration; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010782:Photolysis; D013431:Sulfates / Q000737:chemistry*; D014556:Urine / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D013431:Sulfates; D014874:Water Pollutants, Chemical; C012036:sodium sulfate; D002939:Ciprofloxacin
keywords: Ciprofloxacin; Electro-Fenton; Electrochemical oxidation; Photoelectro-Fenton; Sunlight; Wastewater treatment