硝基苯类物质在铜电极上的电还原特性及pH的影响 |
摘要点击 2049 全文点击 3023 投稿时间:2004-03-04 修订日期:2004-06-21 |
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中文关键词 含硝基苯类化合物废水 循环伏安法 电还原特性 pH 催化铁内电解法 |
英文关键词 wastewater contaminated by nitro-benzene compounds cyclic voltammetry electrochemical reduction characteristics pH the catalyzed iron inner electrolysis method |
DOI 10.13227/j.hjkx.20050221 |
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中文摘要 |
采用循环伏安法,对硝基苯类化合物在铜电极表面上的电还原特性进行了研究,评价了它们在铜电极上的电还原反应活性,并且讨论了这类物质在铜电极上的还原机理和酸度对它的影响.结果表明,硝基苯类化合物能在铜电极表面被直接还原;还原电位在-0.58V和-1.32V左右 (vs. SCE),酸度和碱度均有利于硝基在铜电极上的还原:在碱性条件下容易发生消去反应生成亚硝基;酸性条件下,得电子后的硝基与氢离子之间反应的几率就增大,导致通过溶液的电流值增加,另外,氢的增加也有利于电极上发生的加成和取代反应.pH对不同的硝基苯类物质在铜电极上的电还原特性有不同程度的影响,这主要取决于苯环上其它取代基的性质、结构、数量和它与硝基在苯环上的相对位置.实验结果为催化铁内电解法机理研究提供了理论和实验依据. |
英文摘要 |
The electrochemical reduction characteristics of nitro-benzene compounds were investigated using cyclic voltammetry technique. The reductive reactivity of the nitro-benzene compounds at the copper electrode was evaluated, the reduction mechanisms of the nitrobenzene compounds at the copper electrode and the influences of pH on them were also discussed in this paper. The experimental results show that nitro-benzene compounds is capable of reducing directly at the copper electrode, and the reduction peaks were at -0.58V and -1.32V or so (vs. SCE). Both acidity and basicity favor reduction of nitro-group at the copper electrode: the elimination reaction is easy to occur in the alkaline medium with the formation of nitroso-group; in the acid medium the probability of the reaction between the obtained electrons nitro group and hydrogen ions raises, which causes magnification of the current through the solution; in addition, the growth of hydrogen atoms in number favors the occurring of the addition and substitution reactions at the electrode. pH strongly influenced the electrochemical reduction characteristics of the nitrobenzene compounds at the copper electrode, and it mainly depends on the properties of the substituents on the benzene ring, their configurations and numbers, and their location versus nitro group on the benzene ring. The results provide a theoretical and experimental basis for investigating the reduction mechanisms by the catalyzed iron inner electrolysis process. |
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