【作者】 刘亚纳；

【导师】 严建华； 倪明江； 岑可法；

【作者基本信息】 浙江大学 ， 环境工程， 2008， 博士

【摘要】 本文主要针对气液滑动弧等离子体技术降解有机废水，进行了一系列的基础实验研究工作，主要研究结论如下：（1）对滑动弧等离子体水处理机理进行了分析。（2）以模拟有机废水酸性橙Ⅱ溶液为研究对象，考察了气液滑动弧等离子体反应器的性能参数，废水的性质，废水中含有的无机离子，气体的种类、流量及有机物的结构和种类对降解率的影响．结果表明：综合考虑降解率和能量效率，选择电极厚度为4mm，电极材料为不锈钢，放电电压为10kV；废水初始pH值和温度对降解率的影响不大；从能量效率上考虑，滑动弧放电适合高浓度有机废水的处理；加入体系的正丁醇在反应开始时明显影响了有机物的降解率，但随着降解时间的延长，影响不再明显；体系中CO₃^2-的存在明显影响了有机物的降解率，但随着降解时间的延长，影响变小；NO₃^-对降解率影响可以忽略；随着降解时间的延长和反应的进行，PO₄^3-对有机物降解率的影响不大。载气为氧气时有机物降解率最高，气体流速越大，降解效果越好。高浓度的Cl^-存在时，对降解率产生了较大的影响。气液滑动弧放电等离子体对不同结构的有机染料有广泛的适应性，分子结构不同的染料相互之间有促进的作用。（3）对模拟有机废水酸性橙Ⅱ溶液的降解动力学，降解机理，降解液的可生化性及毒性等进行了研究。结果表明：酸性橙Ⅱ的降解过程符合一级反应动力学规律，降解方程为dC／dt=-0．7587C₀^-0．2889C；降解液的BOD₅／COD_cr值升高，可生化性增强，降解后溶液的毒性降低。通过对降解过程中离子浓度的测定、对降解产物的紫外光谱、红外光谱和GC-MS结果的分析，推测了酸性橙Ⅱ的降解历程。降解后的主要产物是乙酸，乙二酸，丙二酸，苯酚，萘，苯磺酸，邻苯二甲酸（酐），β-萘酚，1,2-萘二酚，3-羟基苯乙酮，甲基萘，1,8-二甲基萘和2,6-二甲基萘等；酸性橙Ⅱ的降解历程是羟基自由基攻击酸性橙Ⅱ分子上的C-N键，导致C-N键断裂，生成对磺基苯二氮烯和β萘酚，磺基苯二氮烯极不稳定，很快转化成苯磺酸，苯磺酸经进一步氧化转化成苯酚；偶氮双键转化为氮气，放电后变为NO₃^-，β萘酚也经一系列氧化转化为苯酚，再经由苯酚降解途径矿化成低分子的有机脂肪酸、二氧化碳和水。（4）为了充分利用滑动弧等离子体放电过程中产生的紫外光，分别开展了与H₂O₂及TiO₂高级氧化工艺联用的研究。结果表明：与H₂O₂联用过程中，溶液的初始pH值对酸性橙Ⅱ降解率的影响可以忽略；氧气气氛下，有利于提高污染物的降解率；放电电压越高，酸性橙Ⅱ的降解效果越好；加入的过氧化氢越多，协同效应越明显，协同效应值越大，降解液放置时间延长有利于酸性橙Ⅱ降解率的提高。与TiO₂联用过程中，二氧化钛浓度为1．0 g/L时，光生电子能量得到最充分的利用，产生的活性粒子最多，H₂O₂的生成量和OH^*的相对量达到最大，酸性橙Ⅱ降解宰达最大值；光解体系中通入氧气，提高了污染物的降解率。滑动弧等离子体与H₂O₂和TiO₂联用，具有显著的协同效应，提高了COD和TOC的降解率，缩短了降解时间，节约了处理成本。（5）以实际有机印染废水为研究对象，研究了滑动弧放电等离子体对其降解的效果。结果表明：废水中CO₃^2-的存在消耗等离子体放电产生的羟基自由基，降低了反应速率，建议通过改变pH加酸方法或者投加生石灰等方法除去CO₃^2-离子；在不考虑CO₃^2-对反应速率影响的基础上，有机废水COD和TOC的降解动力学亦符合一级反应动力学规律。（6）研究了滑动弧等离子体／活性污泥法联合处理有机废水。经滑动弧等离子体处理5 min和10 min的实际印染废水，后续生化处理后，出水COD浓度分别达到GB8978-1996中规定的二级标准和一级标准；色度的去除率均达到GB8978-1996规定的一级标准。（7）最后，以COD浓度为20-30 g／L的废水为研究对象，对滑动弧等离子体／H₂O₂／活性污泥法联合工艺的运行费用进行了估算，并与现有的工艺进行了技术经济比较。结果表明，该联合工艺具有良好的发展前景。更多还原

【Abstract】 This dissertation launched a series of exprimental study, which aims at the effect of gas-liquid gliding arc discharge （GAD） degrading organic wastewater. The objectives of the current research incolved as follows:（1） The mechanisms of gliding arc disposing wastewater are analysed.（2） With Acid OrangeⅡsolution as objective pollutant, the influences of the nature of reactor parameters, the nature of wastewater, inorganic ions contained in the wastewater, the gas flow and the structure and type of organic matter on the degradation rate are studied. The results show that: considering energy efficiency, the gas-liquid GAD is fit for treating high concentration level organic wastewater, and the influences of pH value and temperature are not apparent, and butanol has an obvious impact on the degradation rate at 5min, and the effects of CO₃^2- and high concentration Cl^- is obvious, and the effect of NO₃^- can be ignored, and the effect of PO₄^3- is not apparent after 10min, and the higher gas flow rate, and the higher degradation rate. The different structure of the organic dyes have a wide range of adaptability.（3） Degradation kinetics and degradation mechanism of Acid OrangeⅡ, the solution biodegradability, the toxicity of intermediate products are investigated. The results indicate that the degradation reaction of Acid OrangeⅡfollows the first-order law, and the kinetic pathway could be expressed as follows: dC/dt= - 0.7587C₀ ^-0.2889C. The solution biodegradability was significantly improved, and the toxicity of intermediate products is lower than that of the initial Acid OrangeⅡ. The possible degradation pathway of Acid OrangeⅡis proposed through the analysis of the main intermediates detected by ultraviolet-visible （UV-Vis） spectrum, ion chromatograph （IC） and gas chromatograph coupled with mass spectrophotometer （GC-MS） and fourier transform infrared spectroscopy（FTIR） techniques. The main intermediates are detected during the decomposition such as acetic acid, oxalic acid, malonic acid, phenol, 3-hydroxyhypnone, naphthalene, benzene sulfonic acid, near benzene dicarboxylic acid （anhydride）, 8-naphthalene etc. The possible degradation channel of Acid OrangeⅡis that hydroxyl radicals react with the azo linkage-bearing carbon of a hydroxy substituted ring, with which process substituted phenyldiazene and naphthoxy radical are produced. Both of them are unstable extremely and could react further with hydroxyl radicals resulting in the degradation of aromatic ring.（4） To make full use of UV light produced in GAD, H₂O₂ and TiO₂ are added when plasma discharges. The results show that: when H₂O₂ are added, the initial pH has a little impact on the degradation rate, and oxygen atmosphere and higher discharge voltage are conducive to raise the degradation efficiency of pollutants. The combination H₂O₂ with GAD has a synergetic effect obviously, which increases remarkably decomposition rate and decreases treatment time. When the concentration of TiO₂ is 1.0 g/L, the degradation rate of Acid OrangeⅡis the hightest, because photovoltaic electron energy is used to fully and the more active particles are produced. Oxygen can increase degradation rate. The amount of H₂O₂ and the relative quantity OH^* are the greatest. The removals of COD and TOC increase, and treatment time becomes shorten, and treatment cost has been saved.（5） The industral waste is degraded by gas-liquid GAD. CO₃^2- existing in the wastewater consumes free radicals and decreases degradation rate, and changing initial pH or adding calcium oxide to the wastewater can get rid of CO₃^2-. Without the influence of CO₃^2-, the degradation kinetics also follow first-order law.（6） The industral waste decomposed by the combination GAD with biological treatment is studied. COD removal achieves the relative second and first State Effluent Standard, GB8978-1996, respectively, after biological treatment for 5min treatment and 10min GAD treatment. The removal of color achieves the relative first State Effluent Standard, GB8978-1996.（7） Finally, with COD concentration of 20-30 g/L as objective pollutant, operating costs are estimated for the GAD/H₂O₂/activated sludge, and compared with other existing technology. The results show that the technology has a good prospect for development.更多还原