title: Electrochemical destruction of trans-cinnamic acid by advanced oxidation processes: kinetics, mineralization, and degradation route.
abstract: Acidic solutions of trans-cinnamic acid at pH 3.0 have been comparatively treated by anodic oxidation with electrogenerated H2O2(AO-H2O2), electro-Fenton (EF), and photoelectro-Fenton (PEF). The electrolytic experiments were carried out with a boron-doped diamond (BDD)/air-diffusion cell. The substrate was very slowly abated by AO-H2O2because of its low reaction rate with oxidizing•OH produced from water discharge at the BDD anode. In contrast, its removal was very rapid and at similar rate by EF and PEF due to the additional oxidation by•OH in the bulk, formed from Fenton's reaction between cathodically generated H2O2and added Fe2+. The AO-H2O2treatment yielded the lowest mineralization. The EF process led to persistent final products like Fe(III) complexes, which were quickly photolyzed upon UVA irradiation in PEF to give an almost total mineralization with 98 % total organic carbon removal. The effect of current density and substrate concentration on all the mineralization processes was examined. Gas chromatography-mass spectrometry (GC-MS) analysis of electrolyzed solutions allowed identifying five primary aromatics and one heteroaromatic molecule, whereas final carboxylic acids like fumaric, acetic, and oxalic were quantified by ion exclusion high-performance liquid chromatography (HPLC). From all the products detected, a degradation route for trans-cinnamic acid is proposed.
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: Nelly
authors.initials: N
authors.lastname: Flores
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: Abdoulaye
authors.initials: A
authors.lastname: Thiam
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: Rosa María
authors.initials: RM
authors.lastname: Rodríguez
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: Francesc
authors.initials: F
authors.lastname: Centellas
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: Pere Lluís
authors.initials: PL
authors.lastname: Cabot
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: José Antonio
authors.initials: JA
authors.lastname: Garrido
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. brillas@ub.edu.
authors.forename: Enric
authors.initials: E
authors.lastname: Brillas
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: Ignasi
authors.initials: I
authors.lastname: Sirés
mesh_terms: D002934:Cinnamates / Q000032:analysis / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D008401:Gas Chromatography-Mass Spectrometry; D006861:Hydrogen Peroxide; D007700:Kinetics; D010084:Oxidation-Reduction
chemical_list: D002934:Cinnamates; C029010:cinnamic acid; D006861:Hydrogen Peroxide
keywords: Anodic oxidation; Electro-Fenton; Hydroxyl radical; Oxidation products; Photoelectro-Fenton; Photolysis; Water treatment; trans-Cinnamic acid