【作者】 汤茜；

【导师】 毛志红；

【作者基本信息】 兰州理工大学 ， 环境工程， 2010， 硕士

【摘要】 偶氮染料废水由于其高色度、强毒性、难降解,在还原条件下易分解产生致癌性芳香胺,被视为现今急待治理的废水之一。而传统的废水处理方法都不同程度地存在着各种各样的问题,不能彻底地使有机染料矿化,脱色效率也不高,难以解决水的循环利用问题。电Fenton法作为一种新兴的废水处理技术,集自由基强氧化、电还原作用于一体,能高效降解有机物,已逐渐成为水处理领域的研究热点。本论文以具有典型偶氮染料结构的甲基橙水溶液为目标污染物,采用电Fenton法对其进行降解。实验通过分析槽电压、亚铁离子浓度、电解质浓度及电解时间等因素对甲基橙色度去除效果的影响,得出甲基橙降解的最佳实验条件。在最佳实验条件下,分析了另一种有机底物——表面活性剂存在时,其对甲基橙降解的影响；通过更换阴极材料,分析了阴极材料对甲基橙降解的影响；最后通过甲基橙溶液降解的紫外-可见光谱图和高效液相色谱图,对甲基橙的电Fenton法降解机理进行了初步探讨。实验结果表明,当甲基橙溶液的初始浓度为0.05mmol/L时,在pH值为3、通入空气量为0.1m3/h、Na2SO4和FeSO4浓度分别为14.08mmol/L、0.27mmol/L、槽压为5V的最佳实验条件下时,电解90min,甲基橙溶液的脱色率达98%以上,且甲基橙的降解过程可以采用一级动力学方程来描述。而当表面活性剂SDS和甲基橙共存时,若SDS浓度小于临界胶束浓度,两者同时发生氧化降解反应,甲基橙的脱色反应受到抑制；若SDS浓度大于临界胶束浓度,甲基橙脱色反应的抑制情况得到缓解。通过4种自制的阴极电极在电Fenton法降解甲基橙中的比较可知,当阴极为镀银钢丝电极时甲基橙降解效果最好,脱色率达到99.22%,其后依次为镀钛钢丝电极、钢丝电极和石墨电极,分别为95.98%、93.08%和90.92%,这为今后电Fenton阴极材料的选择提供了新思路。更多还原

【Abstract】 Azo dyes wastewater is not only high chromatic,strong noxious,but also difficult to degrade and easy to discompose to carcinogenic aromatic amine under deoxidization condition.So,azo dyes wastewater must be treated urgently.However, many kinds of problems exist in the conventional wastewater treatment methods, which can not completely mineralize the organic dyes,the decolorization efficiency is not high,and the recycling of water is difficult to solve.As a new wastewater treatment technology, the electro-Fenton method,which includes strong free radical oxidation and electro-deoxidation,can degrade of organic matters efficiently,and it becomes a hot water treatment research in the field gradually.In this thesis,methyl orange solution,which had typical structure of azo dyes, was studied by electro-Fenton method.The best experimental conditions were obtained by the analysis of the influences of operating parameters including electrode potential, Fe2+ concentration,electrolyte Na2SO4 concentration and electrolytic time on the removal rate of methyl orange.Under the best conditions,the effect on the degradation of methyl orange by the surfactant SDS was studied,when it presented in the solution;then the effect of cathode materials on the degradation of methyl orange by replacing the cathode materials was studied,and at last the degradation mechanism of methyl orange was discussed through the analyse of the UV-Visible spectrum and high performance liquid chromatogram.The experimental results showed that,at the best conditions of the initial concentration of methyl orange of 0.05mmol/L,the pH value of 3,the air volume of 0.1m3/h,Na2SO4 and FeSO4 concentrations of 14.08mmol/L,0.27mmol/L,and the electrode potential of 5V,the decolorization rate of methyl orange could exceed 98% when electrolyzing 90min,and the degradation process of methyl orange accorded with first order kinetic equation.When methyl orange coexisted with the surfactant SDS,if the SDS concentration was lower than the critical micelle concentration,the two oxidative degradation reacted simultaneously,and the degradation of methyl orange was limited;The limitation was more significant as the concentration of SDS increased,but the limitation was gradually reduced if the concentration of SDS was higher than the critical micelle concentration.Through the comparison of four different cathodes in electro-Fenton degradation of methyl orange,we could see that,the decoloration value of methyl orange,which could reached 99.22%,was the highest with the silver-gilt steel wire cathode,and then the titanizing steel wire cathode,the steel wire cathode and the plumbaginous cathode in turn,which were 95.98%,93.08% and 90.92% respectively.And this result provided a new idea for the future selection of cathode materials in electro-Fenton method.更多还原