Electro-Fenton and Photoelectro-Fenton Degradation of Sulfanilic Acid Using a Boron-Doped Diamond Anode and an Air Diffusion Cathode

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• 作者：Abdellatif El-Ghenymy ; Jos茅 Antonio Garrido ; Francesc Centellas ; Conchita Arias ; Pere Llu铆s Cabot ; Rosa Mar铆a Rodr铆guez ; Enric Brillas
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：April 5, 2012
• 年：2012
• 卷：116
• 期：13
• 页码：3404-3412
• 全文大小：428K
• 年卷期：v.116,no.13(April 5, 2012)
• ISSN：1520-5215

文摘

The mineralization of sulfanilic acid has been studied by electro-Fenton (EF) and photoelectro-Fenton (PEF) reaction with UVA light using an undivided electrochemical cell with a boron-doped diamond (BDD) anode and an air diffusion cathode able to generate H₂O₂. Organics were then oxidized by hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton鈥檚 reaction between generated H₂O₂ and added Fe²⁺. The UVA irradiation in PEF enhanced the production of hydroxyl radicals in the bulk, accelerating the removal of organics and photodecomposed intermediates like Fe(III)鈥揷arboxylate complexes. Partial decontamination of 1.39 mM sulfanilic acid solutions was achieved by EF until 100 mA cm^鈥? at optimum conditions of 0.4 mM Fe²⁺ and pH 3.0. The increase in current density and substrate content led to an almost total mineralization. In contrast, the PEF process was more powerful, yielding almost complete mineralization in less electrolysis time under comparable conditions. The kinetics for sulfanilic acid decay always followed a pseudo-first-order reaction. Hydroquinone and p-benzoquinone were detected as aromatic intermediates, whereas acetic, maleic, formic, oxalic, and oxamic acids were identified as generated carboxylic acids. NH₄⁺ ion was preferentially released in both treatments, along with NO₃^{鈥?/sup> ion in smaller proportion.}