4-Hydroxyphenylacetic acid oxidation in sulfate and real olive oil mill wastewater by electrochemical advanced processes with a boron-doped diamond anode.
The degradation of 4-hydroxyphenylacetic acid, a ubiquitous component of olive oil mill wastewater (OOMW), has been studied by anodic oxidation with electrogenerated H2O2(AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed in either a 0.050M Na2SO4solution or a real OOMW at pH 3.0, using a cell with a boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2generation. Hydroxyl radicals formed at the BDD surface from water oxidation in all processes and/or in the bulk from Fenton's reaction between added Fe2+and generated H2O2in EF and PEF were the main oxidants. In both matrices, the oxidation ability of the processes increased in the order AO-H2O2<EF<PEF. The superiority of PEF was due to the photolytic action of UVA radiation on photosensitive by-products, as deduced from the quick removal of Fe(III)-oxalate complexes. The effect of current density and organic content on the performance of all treatments was examined. 4-Hydroxyphenylacetic acid decay obeyed a pseudo-first-order kinetics. The PEF treatment of 1.03mM 4-hydroxyphenylacetic acid in 0.050M Na2SO4allowed 98% mineralization at 360min even at low current density, whereas 80% mineralization and a significant enhancement of biodegradability were achieved with the real OOMW.
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.
Nelly
N
Flores
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.
Pere Lluís
PL
Cabot
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.
Francesc
F
Centellas
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.
José Antonio
JA
Garrido
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.
Rosa María
RM
Rodríguez
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.
Enric
E
Brillas
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: i.sires@ub.edu.
Ignasi
I
Sirés
D001895:Boron / Q000737:chemistry*; D018130:Diamond; D055664:Electrochemical Techniques; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007220:Industrial Waste / Q000032:analysis*; D007501:Iron; D007700:Kinetics; D000069463:Olive Oil / Q000737:chemistry*; D010084:Oxidation-Reduction; D010648:Phenylacetates / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D062065:Wastewater / Q000032:analysis*
D001895:Boron; D018130:Diamond; D005296:Ferrous Compounds; D006861:Hydrogen Peroxide; D007220:Industrial Waste; D007501:Iron; D000069463:Olive Oil; D010648:Phenylacetates; D013431:Sulfates; D062065:Wastewater; C045076:Fenton's reagent; C008070:4-hydroxyphenylacetic acid
4-Hydroxyphenylacetic acid; BDD anode; Electro-Fenton; Olive oil mill wastewater; Photoelectro-Fenton