Behavior of dihydroxybenzenes and gallic acid on the Fenton-based decolorization of dyes
Behavior of dihydroxybenzenes and gallic acid on the Fenton-based decolorization of dyes
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DOI：
10.1080/19443994.2014.966333
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发表时间：
2016-01-02
影响因子：
1.1
通讯作者：
Aguiar, Andre
中科院分区：
文献类型：
--
作者：
Barreto, Fernanda;Santana, Cassia Sidney;Aguiar, Andre
二羟基苯（DHB）用作介质，通过芬顿反应增强难降解有机污染物的降解。 DHB 可再生 Fe2+ 离子，从而以比经典芬顿反应更强烈、更连续的方式形成 OH 自由基。目前的工作研究了不同 DHB 和没食子酸（一种三羟基苯）对芬顿体系（Fe2+/H2O2、Fe3+/H2O2）染料溶液脱色的行为。对于大多数 DHB 和没食子酸，在亚甲基蓝、变色剂 2R、甲基橙和酚红的脱色中观察到促氧化特性。这些特性取决于芳环中的羟基位置，并且受目标污染物的结构和氧化还原电位的影响很大。在2,5-二羟基苯甲酸作为介体存在下，类芬顿反应（Fe3+/H2O2）对染料脱色比经典芬顿反应更有效。例如，反应60分钟后，Fe3+/H2O2/2,5-二羟基苯甲酸体系对酚红的脱色率为60%，而Fe2+/H2O2体系的酚红脱色率为40%。 DHBs 和没食子酸增加了染料的脱色，需要最高的 H2O2 消耗量。然而，即使染料溶液没有广泛脱色，H2O2 也会被消耗，这表明部分生成的 OH 自由基与溶液中的 DHB、H2O2 或其他活性物质发生反应。
Dihydroxybenzenes (DHBs) are used as mediators to increase the degradation of recalcitrant organic pollutants by Fenton reaction. DHBs regenerate Fe2+ ions, resulting in the formation of OH radicals in a more intense and continuous manner than the classical Fenton reaction. The present work investigates the behavior of different DHBs and gallic acid (a trihydroxybenzene) on the decolorization of dye solutions by Fenton systems (Fe2+/H2O2, Fe3+/H2O2). For the majority of DHBs and gallic acid, pro-oxidant properties were observed on the decolorization of methylene blue, chromotrope 2R, methyl orange, and phenol red. These properties were dependent on the hydroxyl position in the aromatic ring and were highly influenced by the structure and redox potential of the target pollutant. The dye decolorization by Fenton-like reaction (Fe3+/H2O2) in the presence of 2,5-dihydroxybenzoic acid as mediator was more efficient than classical Fenton reaction. For example, Fe3+/H2O2/2,5-dihydroxybenzoic acid system provided 60% of phenol red decolorization against 40% by Fe2+/H2O2 after 60min of reaction. DHBs and gallic acid increased the decolorization of dyes, requiring the highest H2O2 consumption. However, H2O2 consumption occurred even when the dye solutions were not extensively decolorized, suggesting that part of the generated OH radicals reacted with either DHBs, H2O2 or other reactive species in solution.