Sirés Ignasi, Guivarch Elodie, Oturan Nihal, Oturan Mehmet A
Université Paris-Est, Laboratoire Géomatériaux et Géologie de l'Ingénieur, 5 Bd Descartes, 77454 Marne-la-Vallée Cedex 2, France.
Chemosphere. 2008 Jun;72(4):592-600. doi: 10.1016/j.chemosphere.2008.03.010. Epub 2008 May 19.
Fenton's reagent (Fe2+ +H2O2) has been electrogenerated in situ in an undivided electrolytic cell from the effective reduction of Fe3+ and O2 at carbon-felt cathode for the treatment of aqueous solutions of four triphenylmethane dyes (TPMs), namely malachite green (MG), crystal violet (CV), methyl green (MeG) and fast green FCF (FCF), at pH 3.0 and room temperature. MG has been used as a model among them to study the influence of some experimental parameters on the decay kinetics, COD removal and current efficiency. The results in such electro-Fenton system are explained in terms of the many parasitic reactions involving .OH. Higher efficiency values are obtained with rising organic content and decreasing applied current. The first stage of the mineralization process, involving aromatic by-products, leads to fast decoloration as well as quick initial COD removal that fit well to a pseudo-first-order kinetics. At prolonged electrolysis time, the mineralization rate and efficiency decrease due to the formation of hardly oxidizable compounds and the enhancement of wasting reactions. Solutions of all four TPMs are quickly degraded following a pseudo-first-order decay kinetics. The absolute rate constant (kTPM) for their reaction with .OH increases in the order MeG<FCF<CV<MG. Their degradation rate decreases when they are mixed due to competitive oxidation by .OH. Finally, a mixture containing all four dyes with initial COD ca. 1000 mg l(-1) is totally depolluted with efficiency near 100% at the beginning of the treatment. A general scheme for the mineralization of TPMs is proposed.
在未分隔的电解池中，通过在碳毡阴极上有效还原Fe³⁺和O₂原位电生成芬顿试剂（Fe²⁺ + H₂O₂），用于在pH 3.0和室温下处理四种三苯甲烷染料（TPMs）的水溶液，即孔雀石绿（MG）、结晶紫（CV）、甲基绿（MeG）和亮绿FCF（FCF）。其中以MG作为模型来研究一些实验参数对衰减动力学、化学需氧量（COD）去除率和电流效率的影响。该电芬顿体系中的结果是根据涉及·OH的许多寄生反应来解释的。随着有机含量的增加和施加电流的减小，可获得更高的效率值。矿化过程的第一阶段涉及芳香族副产物，导致快速脱色以及快速的初始COD去除，这与准一级动力学非常吻合。在延长的电解时间下，由于形成难以氧化的化合物以及浪费反应的增强，矿化速率和效率会降低。所有四种TPM的溶液均按照准一级衰减动力学迅速降解。它们与·OH反应的绝对速率常数（kTPM）按MeG＜FCF＜CV＜MG的顺序增加。当它们混合时，由于·OH的竞争氧化，其降解速率会降低。最后，一种含有所有四种染料且初始COD约为1000 mg l⁻¹的混合物在处理开始时以接近100%的效率被完全净化。提出了TPMs矿化的一般方案。
