title: Relationship between anode material, supporting electrolyte and current density during electrochemical degradation of organic compounds in water.
abstract: Taking crystal violet (CV) dye as pollutant model, the electrode, electrolyte and current density (i) relationship for electro-degrading organic molecules is discussed. Boron-doped diamond (BDD) or Iridium dioxide (IrO2) used as anode materials were tested with Na2SO4 or NaCl as electrolytes. CV degradation and generated oxidants showed that degradation pathways and efficiency are strongly linked to the current density-electrode-electrolyte interaction. With BDD, the degradation pathway depends on i: If i<the limiting current density (i(lim)), CV is mainly degraded by OH radicals, whereas if i>i(lim), generated oxidants play a major role in the CV elimination. When IrO2 was used, CV removal was not dependent on i, but on the electrolyte. Pollutant degradation in Na2SO4 on IrO2 seems to occur via IrO3; however, in the presence of NaCl, degradation was dependent on the chlorinated oxidative species generated. In terms of efficiency, the Na2SO4 electrolyte showed better results than NaCl when BDD anodes were employed. On the contrary, NaCl was superior when combined with IrO2. Thus, the IrO2/Cl(-) and BDD/SO4(2-) systems were better at removing the pollutant, being the former the most effective. On the other hand, pollutant degradation with the BDD/SO4(2-) and IrO2/Cl(-) systems is favored at low and high current densities, respectively.
authors: Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín, Colombia.
authors: Fernando L
authors: FL
authors: Guzmán-Duque
authors: Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín, Colombia.
authors: Ricardo E
authors: RE
authors: Palma-Goyes
authors: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, Av. San Rafael Atlixco No 186, C.P 09340, México D.F, Mexico.
authors: Ignacio
authors: I
authors: González
authors: Grupo de diagnóstico y control de la contaminación, Facultad de ingeniería, Universidad de Antioquia, A.A. 1226, Medellín, Colombia.
authors: Gustavo
authors: G
authors: Peñuela
authors: Grupo de Investigación en Remediación Ambiental y Biocatálisis, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía Udea, A.A. 1226, Medellín, Colombia. Electronic address: rtorres@matematicas.udea.edu.co.
authors: Ricardo A
authors: RA
authors: Torres-Palma
mesh_terms: D001895:Boron / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry; D018130:Diamond / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D005840:Gentian Violet / Q000737:chemistry; D007495:Iridium / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002712:Chlorides; D004396:Coloring Agents; D013431:Sulfates; D014874:Water Pollutants, Chemical; C044458:iridium oxide; D007495:Iridium; D018130:Diamond; D005840:Gentian Violet; D001895:Boron
keywords: Boron doped diamond; Electrochemical oxidation; Iridium dioxide; Organic pollutants; Supporting electrolyte type; Water treatment