四种环境污染物电化学降解特性的研究

【作者】 鲁弘懿；

【导师】 王栋；

【作者基本信息】 大连理工大学 ， 环境工程， 2004， 硕士

【摘要】 近年来，由于电化学技术在废水治理中的优势，电化学技术显现了很好的应用前景。电化学方法已用于多个环境污染治理领域，用于电镀废水、化工废水、染料废水、造纸废水、皮革废水、生化废水和制药废水等废水治理。 本文通过构建数据在线采集及记录系统实现实验的自动控制体系，运用循环伏安法、计时电流法和计时电位法等电化学研究方法考察苯胺、氯苯、苯甲酸和硝基苯在铂电极上的电解特性，并对实验进行了现象分析与机理探讨。通过芳香化合物在铂电极上的电解过程及循环伏安扫描行为，得出的主要结论如下：(1)对于苯胺、苯甲酸和硝基苯，在其他条件不变的条件下，峰电流密度随着物种浓度的增加而不断增大。对于苯胺，峰电位不断减小；对于苯甲酸和硝基苯，峰电位变化不大，所以对于这三种物质的高浓度废水，可以采用电化学方法进行处理或预处理；(2)对于苯环上具有吸电子基团的化合物，即hammet常数小于零，循环伏安图表现出氧化峰大于还原峰；对于苯环上具有供电子的基团，即hammet常数大于零，循环伏安图表现出还原峰大于氧化峰，推出：在电解槽中进行的电解，hammet常数小于零的物种，主要发生的反应是电化学氧化，hammet常数大于零的物种，主要的反应是电化学还原反应；(3)苯胺、苯甲酸和硝基苯的峰电流密度随此三种物种的浓度增加而增大，推出电极过程的类型可能是浓差极化，即扩散过程是控制步骤；(4)惰性电解质硫酸钠对于一些电子传递反应只是起到增大溶液电导率，对电子传递没有直接影响，而对于还有的一些电子传递反应，则会影响到电子在极板上的传递过程；(5)苯胺、硝基苯、苯甲酸和氯苯四种物种中，苯胺在电极上电子交换的可逆程度最强，其次是硝基苯，苯甲酸和氯苯。更多还原

【Abstract】 In the last few years, electrochemical technology has been a promising method to dispose wastewater due to its superiority compared with other technologies. The method has been applied to many fields, such as galvanization, chemistry, dye, papermaking, leather, biochemistry and pHarmacy.Electrolysis characteristics of four kinds of aromatic compounds on platinum electrode are studied by cyclic voltammetry, galvanostatic and potentiostat through the on-line gathering and recording system. Some mechanisms related are also discussed. By the electrolysis process and cyclic voltammetry behavior, the conclusions are as follows: (1) Current density grows up with the augment of concentration of aniline, benzoic acid or nitrobenzene if other conditions are not changed. The potential is decreased for aniline and it has little fluctuation for benzoic and nitrobenzene. Therefore, high-concentrated aniline, benzoic acid or nitrobenzene can be disposed by electrochemistry;(2) For compounds that have electron-attracted group in pHenyl, hammet constant less than zero. For compounds that have electron-donor group in pHenyl, hammet constant bigger than zero Therefore, it is concluded that the main reaction path is electrochemical oxidation if hammet constant is less than zero and that the main reaction path is electrochemical reductoin if hammet constant is bigger than zero;(3) Since current density increases as the concentration of aniline, benzoic acid or nitrobenzene is up, control step may be diffusing process; (4) Sodium sulfate is just to make the conductance bigger for simple electro-transferred reaction. While, it will have some effects on complicated electron-transferred process; (5) The sequence of reversibility is aniline, nitrobenzene, benzoic acid, then chlorobenzene and the strongest is aniline.更多还原