Electrochemical incineration of the antimicrobial sulfamethazine at a boron-doped diamond anode

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• 作者：Abdellatif El-Ghenymy ; Pere Lluí ; s Cabot¹ ; Francesc Centellas ; José ; Antonio Garrido ; Rosa Marí ; a Rodrí ; guez ; Conchita Arias ; Enric Brillas¹ ; ^{brillas@ub.edu}
• 关键词：Anodic oxidation ; Boron-doped diamond ; Oxidation intermediates ; Sulfamethazine ; Water treatment
• 刊名：Electrochimica Acta
• 出版年：2013
• 出版时间：15 February, 2013
• 年：2013
• 卷：90
• 期：Complete
• 页码：254-264
• 全文大小：1283 K

文摘

The electrochemical incineration of the antimicrobial sulfamethazine in acidic medium by anodic oxidation (AO) has been studied using an undivided or divided cell with a boron-doped diamond (BDD) anode and a stainless steel cathode. The oxidation power of AO with BDD was greater in the divided than in the undivided cell, as a result of the higher efficiency of reactive hydroxyl radicals generated at the BDD anode from water oxidation. A similar degradation rate was found over the pH range 2.0-6.0. The treatment of a 193 mg dm^?3 drug solution in 0.50 mol dm^?3 Na₂SO₄ at controlled pH 3.0 in the anodic compartment of the divided cell yielded 98 % mineralization for current densities ¡Ý 66.6 mA cm^?2. Analogous almost total mineralization was attained using the undivided cell with 0.05 mol dm^?3 Na₂SO₄ at current densities ¡Ý 100 mA cm^?2, but with lower degradation rate and efficiency. Decreasing current density and increasing drug content enhanced the mineralization current efficiency. Reversed-phase HPLC allowed determining a pseudo-first-order kinetics for sulfamethazine decay, which was faster in the divided cell. 1,2-Benzenediol, 1,4-benzenediol, p-benzoquinone and 4,6-dimethyl-2-pyrimidinamine were identified as aromatic intermediates in the divided cell by gas chromatography-mass spectrometry. Generated carboxylic acids like maleic, fumaric, acetic, formic, oxalic and oxamic were quantified by ion-exclusion HPLC. Ionic chromatography revealed the conversion of the initial N of sulfamethazine into NH₄⁺ ion, along with NO₃^? ion in much smaller proportion. From all detected intermediates, a reaction pathway for sulfamethazine mineralization in acidic medium by AO with BDD is proposed.