Aquatic environment

Electrochemical incineration of dimethyl phthalate by anodic oxidation withboron-doped diamond electrode


HOU Yining , QU Jiuhui , ZHAO Xu , LIU Huijuan

DOI:

Received December 24, 2008,Revised February 24, 2009, Accepted , Available online

Volume 21,2009,Pages 1321-1328

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The anodic oxidation of aqueous solutions containing dimethyl phthalate (DMP) up to 125 mg/L with sodium sulfate (Na2SO4) as supporting electrolyte within the pH range 2.0–10.0 was studied using a one-compartment batch reactor employing a boron-doped diamond (BDD) as anode. Electrolyses were carried out at constant current density (1.5–4.5 mA/cm2). Complete mineralization was always achieved owing to the great concentration of hydroxyl radical (.OH) generated at the BDD surface. The e ects of pH, apparent current density and initial DMP concentration on the degradation rate of DMP, the specific charge required for its total mineralization and mineralization current e ciency were investigated systematically. The mineralization rate of DMP was found to be pH-independent and to increase with increasing applied current density. Results indicated that this electrochemical process was subjected, at least partially, to the mass transfer of organics onto the BDD surface. Kinetic analysis of the temporal change of DMP concentration during electrolysis determined by High Performance Liquid Chromatography (HPLC) revealed that DMP decay under all tested conditions followed a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids were identified by Gas Chromatography- Mass Spectrometry (GC-MS) and a general pathway for the electrochemical incineration of DMP on BDD was proposed.

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