Entity

Time filter

Source Type


Guinea E.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Garrido J.A.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Rodriguez R.M.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Cabot P.-L.,Laboratori dElectroquimica dels Materials i del Medi Ambient | And 3 more authors.
Electrochimica Acta | Year: 2010

Solutions of the veterinary fluoroquinolone antibiotic enrofloxacin in 0.05 M Na2SO4 of pH 3.0 have been comparatively degraded by electrochemical advanced oxidation processes such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF) at constant current density. The study has been performed using an undivided stirred tank reactor of 100 ml and a batch recirculation flow plant of 2.5 l with an undivided filter-press cell coupled to a solar photoreactor, both equipped with a Pt or boron-doped diamond (BDD) anode and a carbon-polytetrafluoroethylene gas diffusion cathode to generate H2O2 from O2 reduction. In EF, PEF and SPEF, hydroxyl radical ({radical dot}OH) is formed from Fenton's reaction between added catalytic Fe2+ and generated H2O2. Almost total decontamination of enrofloxacin solutions is achieved in the stirred tank reactor by SPEF with BDD. The use of the batch recirculation flow plant showed that this process is the most efficient and can be viable for industrial application, becoming more economic and yielding higher mineralization degree with raising antibiotic content. This is feasible because organics are quickly oxidized with {radical dot}OH formed from Fenton's reaction and at BDD from water oxidation, combined with the fast photolysis of complexes of Fe(III) with generated carboxylic acids under solar irradiation. The lower intensity of UVA irradiation used in PEF with BDD causes a slower degradation. EF with BDD is less efficient since {radical dot}OH cannot destroy the most persistent Fe(III)-oxalate and Fe(III)-oxamate complexes. AO-H2O2 with BDD yields the poorest mineralization because pollutants are only removed with {radical dot}OH generated at BDD. All procedures are less potent using Pt as anode due to the lower production of {radical dot}OH at its surface. Enrofloxacin decay always follows a pseudo first-order reaction. Its primary aromatic by-products and short intermediates including polyols, ketones, carboxylic acids and N-derivatives are detected by GC-MS and chromatographic techniques. The evolution of F-, NO3 - and NH4 + ions released to the medium during each process is also determined. © 2009 Elsevier Ltd. All rights reserved. Source


Isarain-Chavez E.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Arias C.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Cabot P.L.,Laboratori dElectroquimica dels Materials i del Medi Ambient | Centellas F.,Laboratori dElectroquimica dels Materials i del Medi Ambient | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2010

Two-electrode cells with a Pt or boron-doped diamond anode and an air-diffusion cathode for H2O2 electrogeneration, and four-electrode combined cells containing the above pair of electrodes coupled in parallel to a Pt anode and a carbon-felt cathode, have been used to degrade the pharmaceutical β-blocker atenolol by electro-Fenton and photoelectro-Fenton methods. In these processes, organics are mainly oxidized with hydroxyl radical ({radical dot}OH) formed simultaneously at the anode surface from water oxidation and from Fenton's reaction between added catalytic Fe2+ and electrogenerated H2O2. Aromatic intermediates such as 4-hydroxyphenylacetamide and p-benzoquinone and generated carboxylic acids such as maleic, fumaric, tartaric, tartronic, glycolic, formic, oxalic and oxamic are detected and quantified by high-performance liquid chromatography. Compared with the single cells, the corresponding novel four-electrode combined systems enhance strongly the mineralization rate of atenolol in electro-Fenton because of the fast Fe2+ regeneration at the carbon-felt cathode favoring: (i) the production of more amounts of {radical dot}OH from Fenton's reaction that destroy more rapidly aromatic pollutants and (ii) the formation of Fe(II) complexes with final carboxylic acids such as oxalic and oxamic, which are more quickly oxidized with {radical dot}OH. In photoelectro-Fenton, both single and combined cells show a quite similar oxidation power giving almost total mineralization as a result of the parallel quick photolysis of Fe(III) and/or Fe(II) complexes under UVA irradiation. The efficient regeneration of Fe2+ with larger {radical dot}OH production in the combined cells causes a quicker atenolol decay, which always follows a pseudo first-order reaction. NH4 + and in smaller proportion NO3 - are always released to the medium. © 2010 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations