【作者】 赵伟荣；

【导师】 汪大翚；

【作者基本信息】 浙江大学 ， 环境工程， 2004， 博士

【摘要】 在确定·OH间接反应速度k_R、光源总辐射流率P_253.7、体积传质系数k_La、反应器有效光程L等工作的基础上，用UV、O₃、O₃／UV等方法处理阳离子红X-GRL染料废水，进行了影响因素研究、动力学研究、机理研究、模型研究、氧化与生化组合研究等。 UV氧化处理研究 通过研究阳离子红X-GRL光降解的影响因素、机理及动力学，得到了如下结论： 1．影响因素研究结果表明：液相溶解氧浓度可强烈地影响光降解效率；染料的转化率随光强的提高而升高；染料的转化率随初始染料浓度的下降而提高；pH对使染料的光降解没有影响；染料的转化率随温度的升高而下降；染料的转化率随投加TBA浓度的升高而下降。 2．光降解机理研究结果表明：存在氧气时，阳离子红X-GRL染料的光降解路径主要有四种机制：激发态染料均裂成自由基，而自由基进一步与氧反应并产生O₂·^-；激发态染料将一个电子转移给基态分子氧使其形成O₂·^-，染料自身形成自由基阳离子并进一步水解：染料由O₂·^-／HO₂降解；激发态染料将一个能量转移给基态分子氧形成¹O₂，而¹O₂可将染料降解。 3．在获得的光降解机理的基础上，运用稳态法得到了不存在TBA时的光降解反应动力学方程，结合描述反应器内辐射能分布的线光源球面辐射模型，可求得光降解总量子产率。 研究表明：不存在TBA时，总量子产率φ_D是温度和溶解氧浓度的函数。回归得到总量子产率φ_D关于温度和溶解氧浓度的Arrhenius修正式：光降解反应的活化能E_a=11.298 kJ·mol^-1。 4．阳离子红X-GRL染料的总量子产率φ_D很低(在10^-3mol·einstein^-1的量级上)，说明染料抗光解能力较强、单独用紫外光降解阳离子红X-GRL染料的效率是很低的，应该采用如O₃、O₃／UV等强氧化能力的处理方法。 O₃氧化处理研究 1．用GC／MS定性和GC半定量等方法确定了阳离子红X-GRL染料在臭氧氧化过程中各中间产物的出现次序及浓度变化，结合臭氧与染料反应的化学计量比、反应过程中溶液pH、TOC的下降和NO₃^-的生成，经基于量子物理的Austin Model 1分子轨道计算软件优化、计算，得出了阳离子红X-GRL的降解脱色机理。染料的臭氧氧化可分为三个阶段：助色基脱落阶段；生色基分解阶段；无色中间产物的进一步降解，形成有机酸、醛、酮及烷烃等有机小分子阶段。确定了染料分子中6个氮的迁移路径：即产生2分子N₂、1分子胺基化合物和1分子NO₃^-。染料的臭氧氧化以直接氧化为主。 2．投加·OH抑制剂TBA研究表明：pH、温度对染料脱色率的影响不明显；提高臭氧气体流量可明显地提高染料的脱色速度；投加TBA时，染料的降解效果略有下降；起始染料浓度对脱色率有负影响。O₃体系化学计量比为4。 pH、臭氧气体流量、起始染料浓度等对直接反应速度常数k_D没有明显的影响；温度对直接反应速度常数k_D有明显的影响。回归得出直接反应速度常数k_D的Arrhenius方程为：其中：指前因子k₀=108810 L·mol^-1·s^-1，活化能E_a=15538 J·mol^-1。 Ha介于0.039和0.083之间，证明反应为慢速反应动力学区域。 3．不存在抑制剂的臭氧氧化研究表明：pH、温度对染料脱色率的影响不明显；提高臭氧气体流量可明显地提高染料的脱色速度；起始染料浓度对脱色率有负影响。 染料的降解反应速度对臭氧和染料各为一级反应、对·OH与染料的间接反应各为一级反应。 DH、温度等对总反应速度常数k_T有明显的影响；提高臭氧气体流量、起始染料浓度对总反应迷度常数k_T没有明显的影响。逝些些全博尘学位论文:阳离子红X一G RL染料的Uv、oJ、。3/uv氧化处理研究 动力学研究得出总反应速度常数析的Arrhenius回归方程为: 气，=ko exp（一气。*/RT）（OH一）m=一08013exp（一5298/R犷）（oH一）。oo，，（L·m。一’·s一’）其中:k0=1050一3L·mol一l·s一’，表观活化能Ea，。bs=一529sJ·mol一‘，参数m=0.0037。 Ho介于0.04!和0.080之间，证明反应为慢速反应动力学区域。 在pH=9.24的碱性条件下，间接反应约占总反应速度的10%左右。随着p日的下降，间接反应。’i总反应速度的比例下降。 4.采川臭氧分解机理、染料降解机理，运用物料衡算、动力学方程来建立染料臭氧氧化的动力学模型。在验证摸型可靠性的基础上，进行了参数敏感性分析。 模型求解中证明模型预测的结果是可靠的，即:预测染料的降解速度的误差大多小于10%;预测液相臭氧浓度与实验测定结果比较接近，但当染料脱色接近完全后，臭氧浓度的预测值偏高，土要是由于预测式中未考虑中间产物对臭氧的消耗，引入了偏差;预测气相臭氧浓度很准确，但由于模型中未考虑中间产物对臭氧的消耗，在反应结束阶段，预测出气臭氧浓度略有偏高;NO3一的生成速度与染料的脱色速度密切相关，受其它因素的影响小，故预测NO3一非常成功;反应开始后数秒内，液相臭氧浓度有急剧的上升，而后很快趋于平缓，说明反应器很快即可达到全混状态。 参数敏感性分析结果表明:气相臭氧分压、臭氧气体流量、抑制剂等因素对染料降解、液相臭氧浓度的累积、出气臭氧浓度、心H浓度、心H间?更多还原

【Abstract】 In this research, wastewater containing Cationic Red X-GRL dye was treated by UV, ozone, and ozone combined with UV, respecively. After determining the OH indirect reaction rate constant kR, the radiation flow rate of UV lamp P253.7, the volumetric mass transfer coefficient kLa, and the effective length of the radiation in photochemical reactor L, the influence factor, mechanism., kinetics, and modeling were investigated for these three processes. UV photooxidation researchIn an immersion photochemical reactor equipped with monochromatic UV light of 253.7nm, the direct photodegradation of Cationic Red X-GRL was studied varying different process parameters, including temperature, pH, concentration of the radical scavenger, light intensity of the lamp, initial concentration of the dye, feeding gas flow rate, and the concentration of the dissolved oxygen. The photodegradation rate equation was derived from a proposed photodegradation mechanism. The quantum yield of reaction was determined from Line Source Spherical Emission Model (LSSE Model), which describes the radiation flow rate absorbed by the solution in the photodegradation process.In the presence of dissolved oxygen, there are four possible photodegradation pathways of Diacryl Red X-GRL under the UV radiation of 253.7 nm in the presence of dissolved oxygen: homolysis of excited dye to radicals; electron transfer of excited dye to form radical dye cation; decomposed by superoxide radical anion; and decomposed by singlet oxygen.The overall quantum yield is a function of temperature, pH, concentration of TBA, and concentration of dissolved oxygen. After non-linear regression analysis, the overall quantum yields can be correlated to a function of the temperature, pH, concentration of TBA, and concentration of dissolved oxygen in a modified Arrhenius expression:with activation energy Ea of 11.298 kJ mol-1.As designed for resisting to UV photodegradation, the quantum yield of dye is very low (at the magnitude of 10-3 mol einstein-1), UV cannot treat the dye easily. O3 oxidation research1. In a semi-batch reactor, experiments of Cationic Red X-GRL degradation by ozonation were developed varying ozone gas flow rate, initial Cationic Red X-GRL concentration, temperature, and pH. When the formation of intermediates and the variation of pH, TOC, and nitrate ion during the ozonation were investigated by the use of some analytical instruments such as GC/MS, GC, and IC, the probable degradation mechanism of the Cationic Red X-GRL in aqueous solution was deliberated with the aid of Austin Model 1 Molecular Orbit (AMI MO) calculations. The N(12)-C(13) site in Cationic Red X-GRL, instead of the N(6)-N(7) site, is found to be the principal site for ozone cycloaddition in the degradation processes. During the degradation process, among the six nitrogen atoms of Cationic Red X-GRL, one is transferred into a nitrate ion, one becomes the form of an amine compound, and the rest four are transformed into two molecules of nitrogen. In the course of the ozonation of Cationic Red X-GRL, the direct attack of ozone is the main decolour effect.2. The ozonation of Cationic Red X-GRL in the presence of TBA, a scavenger of hydroxyl radical, was studied with variation of the ozone gas flow rate, initial Cationic Red X-GRL concentration, temperature, concentration of TBA, and pH.The effect of pH and temperature to conversion of dye are ambiguous, while the ozone gas flow rate can increase the conversion of dye. The conversion of dye was decreased with the increasing concentration ofTBA.The homogeneous experiments performed by mixing separately aqueous solutions of ozone and dye lead to stoichiometric ratio of 4 moles of ozone consumed per mole of dye reacted at various pHs.By the evaluation of the liquid mass transfer coefficient, the interfacial area, and the stoichiometricratio between ozone and Cationic Red X-GRL, the rate constants and the kinetic regime of the reaction between ozone and Cationic Red X-GRL were investigated by applying the experimental data to a更多还原