Abstract:

The mechanism and characteristics of electrochemical oxidation of 1,4-dichlorobenzen in simulated wastewater were investigated on a platinum electrode.The cyclic voltammetric profiles showed that the oxidation peak potential and current density increased with the increase of the concentration of 1,4-dichlorobenzene, nevertheless, the oxidation potential of 1,4-dichlorobenzene in acetonitrile-aqueous solution was smaller than that in acetonitrile solution.Chronoamperometric experimental results suggested that the 1,4-dichlorobenzene degradation included both direct electro-oxidation of 1,4-dichlorobenzene by loss of electrons and indirect oxidation with anodically formed free radicals.Additionally, parachlorophenol, 1,4-benzoquinone, maleic acid, oxalic acid, acetic acid,and formic acid were identified as main electro-oxidation products by ion chromatography or high performance liquid chromatography.Moreover, a yellow polymer film, which influenced the electrochemical oxidation process, was clearly identified as a rough surface after electrochemical reaction in comparison to a smooth and glossy surface of platinum electrodes without polymer film as observed from SEM image.

Key words:

1,4-二氯苯, 电氧化, 乙腈-水

摘要： 为有效去除化工废水中的1,4-二氯苯，研究了Pt电极上乙腈-水混合溶剂中1,4-二氯苯电氧化机理。计时电流法研究表明，氧化过程中既有电极表面失电子的直接电化学氧化，又有基于活性自由基的间接氧化。通过SEM表征和Pt电极表面观察，证明Pt电极在2.3 V(vs. SCE)的电位下氧化p-DCB过程中，表面存在黄色有机聚合物膜，致使体系的导电性变差。降解途径推断表明，反应首先经历了脱氯和对氯酚、对苯醌等芳香类中间体的生成；接着开环生成小分子有机酸；最后小分子羧酸进一步氧化成CO₂。

关键词:

1,4-二氯苯, 电氧化, 乙腈-水