Comparative electrochemical oxidation of methyl orange azo dye using Ti/Ir-Pb, Ti/Ir-Sn, Ti/Ru-Pb, Ti/Pt-Pd and Ti/RuO2 anodes
Isarain-Chávez, Eloy. (Universitat Autònoma de Barcelona. Departament de Física)
Baró, M. D.. (Universitat Autònoma de Barcelona. Departament de Física)
Rossinyol Casals, Emma (Universitat Autònoma de Barcelona. Servei de Microscòpia)
Morales-Ortiz, Ulises (Universidad Autónoma Metropolitana (Mèxic))
Sort Viñas, Jordi (Universitat Autònoma de Barcelona. Departament de Física)
Brillas, Enric (Universitat de Barcelona. Departament de Química Física)
Pellicer Vilà, Eva Maria (Universitat Autònoma de Barcelona. Departament de Física)

Data:	2017
Resum:	The relative oxidation power of dimensionally stable anodes, namely Ti/Ir-Pb, Ti/Ir-Sn, Ti/Ru-Pb, Ti/Pt-Pd and Ti/RuO₂, has been determined from the anodic oxidation (AO) treatment of 2 dm³ of methyl orange azo dye solutions in 0. 050 mol dm¯³ Na₂SO₄ of pH 7. 0 at constant current density. The anodes were synthesized by the dip-coating method using the corresponding metallic chlorides in isopropanol/water and their morphology, surface roughness, crystallographic structure and composition were analyzed. A mixture of IrO₂, Pb₂O₃ and Pb₃O₄ were the components in the outperforming Ti/Ir-Pb anode. The effect of current density, Na₂SO₄ concentration, and cathode nature on the decolorization of azo dye solutions by AO with Ti/RuO₂ was examined. Under favorable conditions, 96%-98% color removal was achieved using Ti/Ir-Pb, Ti/Ir-Sn and Ti/Ru-Pb, with lower decolorization for Ti/Pt-Pd and Ti/RuO₂ anodes. In all cases, a pseudo-first-order decolorization process was found. The oxidation ability of anodes rose in the order Ti/RuO₂< Ti/Pt-Pd < Ti/Ru-Pb < Ti/Ir-Sn < Ti/Ir-Pb, achieving 76. 0% mineralization for the latter electrode. The mixture of active and non-active materials then gave rise to anodes with higher oxidation power than those made solely of active materials, due to the enhancement of the oxidation action of hydroxyl radicals formed in the non-active oxide. The superiority of Ir over Ru in the mixed metal oxides was related to the greater adsorption of organics on its surface, thereby favoring their oxidation. Ammonium and sulfate ions were released as pre-eminent ions. Stable byproducts and final short-linear aliphatic carboxylic acids were identified by gas chromatography-mass spectrometry and ion-exclusion high-performance liquid chromatography. Based on these compounds, a reaction sequence for methyl orange mineralization is proposed.
Ajuts:	Ministerio de Economía y Competitividad MAT2014-57960-C3-1-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1015
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Azo dye ; Anodic oxidation ; Dimensionally stable anodes ; Oxidation products ; Wastewater treatment
Publicat a:	Electrochimica acta, Vol. 244, (Aug.2017) , p. 199-208, ISSN 1873-3859

DOI: 10.1016/j.electacta.2017.05.101

Postprint 19 p, 2.6 MB

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Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Ciències > Grup de nanoenginyeria de materials, nanomagnetisme i nanomecànica (Gnm3)
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