Abstract

NAVA, José L.; QUIROZ, Marco A.  and  MARTINEZ-HUITLE, Carlos A.. Electrochemical Treatment of Synthetic Wastewaters Containing Alphazurine A Dye: Role of Electrode Material in the Colour and COD Removal. J. Mex. Chem. Soc [online]. 2008, vol.52, n.4, pp.249-255. ISSN 1870-249X.

The electrochemical oxidation of Alphazurine A (αzA) has been studied in Na₂SO₄ media at Ti/IrO₂, Pb/PbO₂ and boron-doped diamond (Si/BDD) electrodes by bulk electrolysis experiments under galvanostatic control at j = 30 and 60 mA cm^-2. The obtained results have clearly shown that the electrode material plays an important role for the electrochemical incineration of azA, where Pb/PbO₂ and Si/ BDD lead complete mineralization of dye, while Ti/IrO₂ disfavoured such process. The complete mineralization of ±zA on Pb/PbO₂ and Si/BDD is due to the production of hydroxyl radicals on these materials surfaces. Current efficiencies obtained at Ti/IrO₂, Pb/PbO₂ and Si/ BDD gave values of 3, 24 and 42%, for each electrode material, at 30 mA cm^-2, respectively. These values were higher than those obtained at 60 mA cm^-2. Energy consumption values from the electrolyses performed at 30 mA cm^-2 were 254, 124 and 51 kWh m^-3, for Ti/IrO₂, Pb/PbO₂ and Si/BDD, respectively. UV spectrometric measurements showed faster αzA elimination at the Si/BDD electrode than those obtained on Ti/IrO₂ and Pb/PbO₂.

Keywords : Anodic oxidation; dyes; boron doped diamond electrode; iridium dioxide electrode; lead dioxide electrode.

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