【作者】 陈武；

【导师】 杨昌柱；

【作者基本信息】 华中科技大学 ， 环境工程， 2007， 博士

【摘要】 有机物是对水质和水生态环境影响最严重的污染物之一,有机物污染是目前全球水污染最典型的特征,它不仅带来了一系列的环境问题,还严重危害人们生活和身体健康。因此,有机废水的治理已经成为现阶段环境保护领域亟待解决的问题。三维电极处理有机废水有很高的电流效率和很好的水处理效果,但目前技术还不成熟,有很多问题有待解决,如对粒子电极及主电极的研究和优选、各项操作参数的优化还缺乏系统深入研究,对电化学反应历程、有机物降解的机理还没有统一认识等,因此,开展三维电极处理有机废水研究具有重要意义和价值。本论文主要研究了三维电极处理模拟有机废水的效果、降解有机物的机理、降解规律、降解反应过程动力学,同时还对三维电极与Fenton试剂法联用技术进行了研究。论文的主要研究内容和结果包括:1.三维电极处理模拟PAM废水的实验研究(1)为了研究三维电极的主电极和粒子电极,进行了去除模拟PAM废水COD效率对比实验及电镜扫描实验,结果表明,用不锈钢作三维电极的主电极对废水COD去除效率最高,不锈钢材料耐蚀性能最好;三维电极中填充的活性炭确实成了粒子电极。(2)通过研究影响三维电极去除废水中PAM各种因素发现,三维电极对PAM废水COD的去除效率受主电极材料、主电极间距、电解时间和电解电流等的显著影响;三维电极在最佳条件降解0.1%PAM模拟废水有很好的效果,废水COD值由初始的1120mg/L降低到96mg/L,COD去除率达到了91%,废水中PAM含量也由1000mg/L降低到47mg/L,三维电极降解0.1%PAM废水的动力学反应为二级。2.三维电极降解废水中PAM机理研究为了弄清三维电极降解PAM的机理,分析了处理后水样中不溶物的红外光谱及CO32-、HCO3-,并采用Ti(Ⅳ)-5-Br-PADAP法和比色法检测了处理后水样中的H2O2及·OH自由基,结果表明,不溶物是PAM发生分子内反应生成的环状酰亚胺结构产物;处理后水样中有HCO3-、H2O2和·OH,说明有PAM分子被彻底降解为CO2、H2O,不溶物和H2O2及·OH都是废水中PAM浓度和COD降低的原因。最后推导了·OH自由基降解PAM的可能反应历程。3、三维电极处理L-亮氨酸废水研究(1)研究了L-亮氨酸模拟废水COD与其降解率关系,结果表明,三维电极对1.0g/L的模拟废水中L-亮氨酸降解率越大,COD去除率也越大。(2)三维电极电位分布研究结果表明,反应器中电位分布是不均匀的,它受废水浓度、主电极材料、电解槽端电压等的显著影响,并且与COD去除率有关。(3)研究了各因素对三维电极处理L-亮氨酸模拟废水效率的影响。在由正交试验得到的填充活性炭和陶粒时三维电极处理1.0g/L L-亮氨酸模拟废水的最佳操作条件下,COD去除率分别为90%和88%。三维电极处理低浓度和高浓度L-亮氨酸废水时,降解反应分别为一级反应和零级反应。4、三维电极方法处理多组分氨基酸废水研究(1)三维电极处理多组分氨基酸废水规律研究表明,多组分氨基酸废水体系总降解率越大,其COD去除率也越大;各组分去除难度由大到小依次为:L-亮氨酸>L-酪氨酸>L-精氨酸>L-组氨酸>L-半胱氨酸;(2)处理多组分氨基酸混合废水实验表明,二组分混合时,L-亮氨酸与L-半胱氨酸或L-酪氨酸混合时的降解率为最高或最低,废水COD去除率相应的为最高或最低;三组分混合时,L-亮氨酸+L-酪氨酸+L-半胱氨酸混合废水总降解率(55%)、COD去除率(90%)都大于L-亮氨酸+L-酪氨酸+L-精氨酸混合废水总降解率(38%)和COD去除率(84%);四、五组分氨基酸混合时,四组分总的降解率、COD去除率分别为51%、88%,均大于五组分总降解率47%、COD去除率86%;(3)分析了氨基酸的分子结构和·OH自由基与有机物反应的特点,结合氨基酸的前线轨道能隙值的大小,解释了不同氨基酸在相同条件下降解难易程度不同的原因。5、三维电极—Fenton试剂法联用技术研究研究了多种因素对三维电极—Fenton试剂法联用去除废水COD的影响,在最条件下,二者联用对模拟对苯二酚废水COD去除率达92%。在相同条件下,其处理废水效率高于Fenton法和三维电极法,对废水COD去除率分别为89%、53%和41%,说明三维电极—Fenton试剂法联用具有一定的可行性。6、三维电极处理废水可行性研究(1)三维电极分别静态处理含氨基酸和含聚合物实际废水,COD去除率分别为68%和83%;动态处理含聚合物实际废水,COD去除率达87%。(2)用三维电极静态处理含氨基酸或含聚合物实际废水最高电耗分别为9kW·h/ kgCOD和8kW·h/ kgCOD,时空产率都为3.0kgCOD/h·m3,法拉第电流效率大小分别为1375%和1450%;动态处理含聚合物实际废水最高电耗为12kW·h/ kgCOD,法拉第电流效率为1003%。废水的原始COD越高,法拉第电流效率就越高,最大电耗就越小。更多还原

【Abstract】 Organic substance is one of the most serious pollutants that affect the water quality and water ecological environment. Pollution caused by organic substance is a typical feature of global water pollution, which not only leads to a series of environmental pollution, but also seriously imperils people’s life and health. As a result, the treatment of organic wastewater has been an urgent problem to be solved. A method of three-dimensional electrode (TDE) which applied to wastewater treatment has high electric current efficiency and desired treatment effect. However, the technique, at present, is immature and there are some key problems to be solved. For example, systematical and thorough research is deficient in the study on the optimization of particle electrode, main electrode and the optimization of various operational parameters.Moreover,an agreement about the reaction process of electrochemistry and the mechanism of TDE degrading organic substance have not been reached. Therefore, a study on TDE treating organic wastewater has tremendous significance and value. This dissertation studies the effect of TDE,degrading mechanism of TDE, degrading regularity of TDE and degrading reaction kinetics when TDE is used to treat simulated organic wastewater. In addition, a TDE-Fenton method is explored in the dissertation. The main research content and research result include:1. Experiment of using TDE to treat wastewater containing polyacrylamide(PAM)(1) In order to study the main electrode and particle electrode of TDE, the COD removal ratio comparison by experimentally and scanning electron microscopy (SEM) is carried out. The result shows that the main electrodes made of stainless iron have the best COD removal efficiency. Moreover,electrodes made of stainless iron are the most resistive to the corrosion and active carbon packed in TDE has indeed lead to a particle electrode.(2) Studying various factors that affect TDE to remove PAM contained in wastewater shows that the COD removal ratio by TDE treating wastewater is significantly influenced by the main electrode material, space between the main electrode, electrolysis time and electrolysis current. Under the optimum operational condition, TDE has a satisfied effect of degrading wastewater containing 0.1% PAM, The COD of simulated wastewater containing 0.1%PAM is reduced from the initial of 1120.0mg/L to 96mg/L, and the COD removal efficiency reaches 91%. Morever PAM containing in wastewater also decreases from 1000mg/L to 47mg/L. The degrading reaction of 0.1%PAM is considered as a second order reaction by using TDE.2. Study on mechanism of TDE degrading wastewater containing PAMIn order to make clear the mechanism of TDE degrading wastewater containing PAM, infrared spectrum of insoluable substance in sample after treatment is analyzed. A method referred to Ti(Ⅳ)-5-Br-PADAP and the colorimeter test for the existence of H2O2 and·OH free radicals in sample after treatment are employed. It is found that the insoluable substance is the formation of imide group via cyclization. The existence of HCO3-, H2O2 and·OH indicates that the PAM molecule is completely degraded into CO2、H2O and that the generation of insoluable substance and H2O2 and·OH are responsible for the decrease of PAM concentration and COD. At last, the possible reaction process of·OH free radical degrading PAM is deduced.3. Study onTDE treating L-leucine contained wastewater(1)The experiment studies the relationship between the COD removal ratio and L-leucine degrading ratio. It is demonstrated that when TDE treats wastewater containing 1.0g/L leucine, the higher degrading ratio of L-leucine results in, the bigger COD removal efficiency.(2) The study on the electric potential distribution of TDE shows that the electric potential distribution is uneven in the reactor, which is significantly affected by the wastewater concentration, main electrode material and the terminal voltage of electrobath has something to do with the COD removal ratio.(3) The experiment studies the influence of factors on the treating efficiency of TDE with different packed particles (activate carbon, ceramic particle). Through orthogonal experiment, the optimum operational condition of TDE packed with either activate carbon or ceramic particle is obtained for treating the simulated wastewater containing 1.0g/L- leucine. Under this condition, the COD removal efficiencies are 90% and 88%, respectively. With TDE treating low-concentration and high-concentration wastewater containing L-leucine, the degrading reaction is a first order reaction and a zeroth order reaction, respectively.4. Study on TDE treating wastewater containing multi-component amino acid(1) The study on TDE treating wastewater containing multi-component amino acid illustrates that the higher the general degraddation ratio of wastewater containing multi-component amino acid is, the higher COD removal efficiency is. The degraddation of different components of amino acid becomes difficult fowling the order from difficult to easy: L-leucine>L-tyrosine>L-arginine >L-histidine>L-cysteine.(2) Treating mixed wastewater of containing multi- component amino acid mixed shows that when mixing two-component amino acids, the degrading ratio of L-leucinie mixing with L-cysteine or mixing with L-tyrosine is the highest or the lowest, the COD removal ratio is the highest or the lowest,relevantly. When mixing three-component amino acids, the general degrading ratio (55%) and the COD removal ratio (90%) of wastewater containing L-leucine and L-tyrosine and L-cysteine is higher than those of wastewater containing L-leucine and L-tyrosine and L-arginine. When mixing 4 or 5 component amino acids,the general degrading ratio and COD removal ratio of wastewater containing 4-component amino acids are 51% and 88%, respectively,higher than the degrading ratio 47%and COD removal ratio 86% for 5- component..(3)Based on the molecule structure of amino acid, and the feature of the reaction of·OH radical with organic substance, and different energy-gap of frontier orbital of amino acid,the reason why different amino acids in wastewater under the same condition has different degrading effects has been explained.5. Study on TDE-Fenton methodThe experiment studies the effect of factors influencing the COD removal ratio of TDE-Fenton method. Under the optimum conditions, the COD removal ratio of TDE-Fenton method treating simulated organic wastewater containing hydroquinone can reach 92%. Under the same conditions, the TDE-Fenton method has a better degrading effect than either Fenton agent or TDE. The COD removal ratios are 89%、53% and 41% for TDE-Fenton,Fenton and TDE,respectively, demonstrating that the TDE-Fenton method has definite a feasibility.6. The feasibility study of TDE on teat wastewater (1)TDE is used to treat a real wastewater containing amino acid and wastewater containing polymer statically. The COD removal ratios are 68% and 83%,respectively While treating a real wastewater containing polymer dynamically by TDE,the COD removal ratio is 87%.(2) When TDE is used to treat a real wastewater containing amino acid and polymer statistically, the maximum electrical consumption is 9kW·h/kgCOD and 8kW·h/kgCOD respectively and the space-time yield is both 3.0kgCOD/h·m3.The Faradic current efficiencies are 13756% and 1450%,respectively. When TDE is utilized to treat the real wastewater containing polymer dynamically, the maximum electrical consumption is 12kW·h/ kgCOD. The Faradic current efficiency is 1003%. Higher the original COD in wastewater is, higher the Faradic current efficiency is, whereas smaller the maximum electrical consumption is.更多还原