title: Mineralization of sulfanilamide by electro-Fenton and solar photoelectro-Fenton in a pre-pilot plant with a Pt/air-diffusion cell.
abstract: The mineralization of sulfanilamide solutions at pH 3.0 was comparatively studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF) using a 2.5 L pre-pilot plant containing a Pt/air-diffusion cell coupled with a solar photoreactor. Organics were primordially oxidized by hydroxyl radical (OH) formed from Fenton's reaction between H₂O₂ generated at the cathode and added Fe(2+) and/or under the action of sunlight. A mineralization up to 94% was achieved using SPEF, whereas EF yielded much poorer degradation. The effect of current density and Fe(2+) and drug concentrations on the degradation rate, mineralization current efficiency and energy cost per unit DOC mass of EF and/or SPEF was examined. The sulfanilamide decay always followed a pseudo first-order kinetics, being more rapid in SPEF due to the additional generation of OH induced by sunlight on Fe(III) species. Catechol, resorcinol, hydroquinone and p-benzoquinone were identified as aromatic intermediates. The final solutions treated by EF contained Fe(III) complexes of maleic, fumaric, oxamic and mainly oxalic acids, which are hardly destroyed by OH. The quick photolysis of Fe(III)-oxalate complexes by sunlight explains the higher oxidation ability of SPEF. The N content of sulfanilamide was mainly mineralized as NH₄⁺ ion and in much lesser extent as NO₃⁻ ion, whereas most of its initial S was converted into SO₄²⁻ ion.
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: Abdellatif
authors.initials: A
authors.lastname: El-Ghenymy
authors.forename: Pere Lluís
authors.initials: PL
authors.lastname: Cabot
authors.forename: Francesc
authors.initials: F
authors.lastname: Centellas
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Garrido
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Rodríguez
authors.forename: Conchita
authors.initials: C
authors.lastname: Arias
authors.forename: Enric
authors.initials: E
authors.lastname: Brillas
mesh_terms: D000388:Air; D004058:Diffusion; D055664:Electrochemical Techniques; D004566:Electrodes; D052918:Environmental Restoration and Remediation; D005290:Ferric Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D010782:Photolysis; D010865:Pilot Projects; D010984:Platinum / Q000737:chemistry*; D000077145:Sulfanilamide; D013424:Sulfanilamides / Q000737:chemistry*; D013472:Sunlight; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: C045076:Fenton's reagent; D005290:Ferric Compounds; D013424:Sulfanilamides; D014874:Water Pollutants, Chemical; D000077145:Sulfanilamide; D017665:Hydroxyl Radical; D010984:Platinum; D006861:Hydrogen Peroxide; D007501:Iron