Nasr Bensalah, Abdellatif Gadri, Cañizares Pablo, Sáez Cristina, Lobato Justo, Rodrigo Manuel A
Department de Chimie Industrielle, Institut Supérieur des Sciences Appliquées et Technologie de Genès, Université de Genès, 6072 Zrig, Genès, Tunisie.
Environ Sci Technol. 2005 Sep 15;39(18):7234-9. doi: 10.1021/es0500660.
The electrochemical oxidation of aqueous wastes polluted with hydroquinone, resorcinol, or catechol on boron-doped diamond electrodes has been studied. The complete mineralization of the organic waste has been obtained independently of the nature of each isomer. No aromatic intermediates were found during the treatment, and solely aliphatic intermediates (carboxylic acids C4 and C2, mainly) were detected in the three cases. Although as from the bulk electrolyses study no differences in the electrochemical oxidation of dihydroxybenzenes seem to exist, different voltammetric behavior between resorcinol and the other two isomers was obtained in the voltammetric study. Catechol and hydroquinone have a reversible quinonic form, and a cathodic reduction peak appears in their voltammograms. The characterization of the first steps in the electrochemical oxidation of the three dihydroxybenzenes showed the formation of a larger number of intermediates in the oxidation of catechol, although no carbon dioxide was detected in its oxidation. Conversely, the oxidation of resorcinol and hydroquinone lead to the formation of important concentrations of carbon dioxide. The nondetection of aromatic intermediates, even if small quantities of charge are passed, confirms that the oxidation must be carried out directly on the electrode surface or by hydroxyl radicals generated by decomposition of water.
研究了对苯二酚、间苯二酚或邻苯二酚污染的水性废物在掺硼金刚石电极上的电化学氧化。无论每种异构体的性质如何，都实现了有机废物的完全矿化。处理过程中未发现芳香族中间体，仅在三种情况下检测到脂肪族中间体（主要是C4和C2羧酸）。尽管从本体电解研究来看，二羟基苯的电化学氧化似乎没有差异，但在伏安研究中，间苯二酚与其他两种异构体表现出不同的伏安行为。邻苯二酚和对苯二酚具有可逆的醌型，其伏安图中出现阴极还原峰。三种二羟基苯电化学氧化第一步的表征表明，邻苯二酚氧化过程中形成的中间体数量更多，尽管其氧化过程中未检测到二氧化碳。相反，间苯二酚和对苯二酚的氧化导致大量二氧化碳的形成。即使通过少量电荷也未检测到芳香族中间体，这证实氧化必须直接在电极表面进行，或通过水分解产生的羟基自由基进行。
