【作者】 秦祖赠；

【导师】 刘自力；

【作者基本信息】 广西大学 ， 化学工艺， 2007， 硕士

【摘要】 液相高压放电等离子体降解技术涉及等离子体物理、等离子体化学、高温热解、光化学氧化、液电空化降解、超临界水氧化、臭氧化等多种水处理方法的综合效应，不产生二次污染，是一种对水资源污染严重的造纸、制药、印染等生物难降解有机废水较理想的和有潜力的水处理技术。将液电等离子体与催化剂协同作用，能利用高压放电的能量，使液电等离子体过程得到强化。以降解含2，4-二硝基苯酚废水为探针反应，研究液电等离子体及液电等离子体协同TiO₂催化降解含酚废水过程。在单独使用液电等离子体降解2，4-DNP时，在16kV下反应30min，2，4-DNP基本被降解，反应10min降解70％，随着反应时间的增加，有混浊残渣出现。废水经过液电等离子体降解后，形成等离子体酸类物质，使其pH值降到3.30左右，电导率增加到300μS·cm^-1。废水初始电导率增加会抑制液电等离子体放电过程；2，4-DNP初始浓度降低，降解速率增加；其初始pH值在4.00左右时，降解率最高；空气流速对2，4-DNP的影响不大，鼓入空气可提高气液传质，利于酚类降解。TiO₂、WO₃、SnO₂、CdS、LaCoO₃、Fe₂O₃、MnO₂、Bi₂WO₆等八种半导体催化剂在液电等离子体条件下对2，4-DNP的降解不遵循光催化一般原理，其中TiO₂协同液电等离子体催化降解2，4-DNP的效果最好。WO₃附载到TiO₂上未使其在液电等离子体中对2，4-DNP的催化降解效率增加。采用氨水为沉淀制备的TiO₂的活性要比采用NaOH的好；在TiO₂制备过程中，氯离子的存在能影响到催化的活性；采用673K温度焙烧的TiO₂的活性要明显高于其它温度焙烧的催化剂。使用液电等离子体降解及液电等离子体协同TiO₂催化降解2，4-二硝基苯酚的过程均符合一级反应，即-ln（c／c₀）=kt+k₀。降低2，4-DNP的浓度及提高放电电压，均可提高降解速率。催化剂TiO₂的加入，能提高2，4-DNP的降解速率，在16kV，初始浓度为50mg·L^-1，TiO₂加量为0.15％时，降解速率最大，其催化效应增强因子为1.546。放电电压对2，4-DNP的影响大，在液电等离子体及液电等离子体协同TiO₂的作用下，放电电压与反应速率常数的关系分别为k=9.11×10^-3e^0.15791U、k=21.38×10^-3e^0.13073U。TiO₂的焙烧温度对其协同催化液电等离子体的催化活性有影响，最佳焙烧温度为673K，焙烧温度直接影响催化剂的晶相结构。通过一系列的表征数据说明，在液电等离子体中使用TiO₂作为催化剂，不能套用光催化的一般理论。TiO₂催化剂的表面羟基随着其焙烧温度的增加而减少，表面羟基的数量能直接影响到其催化活性。在低温焙烧时TiO₂不能形成锐钛矿型，不能形成足够的晶格缺陷。更多还原

【Abstract】 The technology of high-voltage discharge plasma degradation relates to a wide range of disciplines such as plasma physics, plasma chemistry, hydromechanics, thermodynamics, kinetics, high-voltage technology, and environmental engineering. The plasma degradation processes the synergistic effects of many water treatment technologies such as high temperature pyrolysis, photochemical oxidation, liquid electric cavitation degradation, superciritical water oxidation, and ozonization. It does not cause secondary pollution in treatment. It is one of the potentially applicable wastewater treatment technologies for treating refractory organic pollutants wastewaters such as papermaking wastewater, pharmaceutical wastewater and dyeing wastewater, the pollute water resource severely. Synergied hydro-plasma and catalyst would ultilize the high-voltage discharge energy greatly, and enhance the hydro-plasma discharge process.The hydro-plasma degraded high concentration 2,4-dinitrohpenol wastewater was preliminary discussed, and the process conditions of which influenced the degradation of 2,4-DNP wastewater by hydro-plasma was researched.With 2,4-dinitrophenol degradation in wastewater as a probe reaction, the process of hydro-plasma degraded and hydro-plasma combined with TiO₂ catalytic degraded phenols wastewater were studied. Used hydro-plasma degraded 2,4-DNP solely, under a voltage of 16kV, and a treated time of 30min, the 2,4-DNP was degraded completely, at 10min, the degradation rate was 70％, and with the increasing of reaction time, there was some opacity residues. Some kind of plasma acid was formed in wastewater after degraed by hydro-plasma, pH dropped to 3.30, and conductivity increased to 300μS.cm^-1. The hyro-plasma discharge process would be restrained by the high initial conductivity. And the lower initial 2,4-DNP concentration, the higher degradation rate, the greater the degradation rate. When the pH was 4.00, the degradation rate was highest. The influence of air velocity on 2,4-DNP degradation was not so big, blew in lots of air can raise gas-liquid mass transfer, helped phenols degradation.TiO₂、WO₃、SnO₂、CdS、LaCoO₃、Fe₂O₃、MnO₂ and Bi₂WO₆ were semiconductor, they degraded 2,4-DNP in hydro-plasma did not follow the general principles of photocatalytic, among them, TiO₂ got a better catalysis effect. TiO₂ coated with WO₃ could not increase the catalytic degradation efficiency of 2,4-DNP in hydro-plasma. The catalysis activity of TiO₂ Preparaed by ammonia precipitation was better than NaOH precipitation. The existence of chloride ions can greatly affect the catalytic activity in the process of TiO₂ preparation. And the catalysis activity of TiO₂ at calcination Temperatureof 673K was significantly higher than at the other.The process of hydro-plasma degraded and hydro-plasma combined with TiO₂ catalytic degraded 2,4-DNP wastewater were first order reaction, -ln（c/co）=kt+k₀. Reduced the 2,4-DNP concentration or rasied the discharge voltage could increase the degradation rate. the added of TiO₂ would enhance the degradation rate of 2,4-DNP, the degradation rate was highest at a initial concentration of 50mg·L^-1 and a TiO₂ dosage of 0.15％, and the catalytic effect enhance factor was 1.546. The discharge voltage was very great impact to 2,4-DNP degradation, and at the hydro-plasma degraded and hydro-plasma combined with TiO₂ catalytic degraded 2,4-DNP wastewater, the relation between discharge voltage and reaction rate constant was k=9.11×10^-3e^0.15791Uand k=21.38×10^-3e^0.13073U respectively.The calcination temperature of TiO₂ was great effect on the catalyticactivity of it combined with hydro-plasma, the optimum calcination temperaturewas 673K. The calcination temperature directly affected the crystalline structureof catalyst from the XRD patten and thermal analysis. A series ofcharacterization data shows that using TiO₂ as catalyst in hydro-plasma couldnot follow the general principle of photocatalytic. The suface hydroxyl groups ofTiO₂ decreased with the calcination temperature increase, and the amount ofsuface hydroxyl groups could impact on the catalytic activity. The crystal ofTiO₂ was not anatase in low calcination temperature, and could not form enoughlattice defects.更多还原