非均相催化—臭氧氧化降解愈创木酚的研究

发布时间：2018-07-04 16:16

本文选题：AlOOH + 臭氧　；参考：《天津科技大学》2017年硕士论文

【摘要】：木素作为造纸废水中的主要污染物,愈创木酚(GL)是其中一种模型物,其结构由三部分组成:苯环、羟基、甲氧基,作为一种有机污染物,运用物理法、化学法、生物法等难以将这种污染物彻底降解,达到达标排放。本实验选用非均相催化臭氧氧化技术对愈创木酚溶液进行降解。在催化臭氧氧化的实验中催化剂的选择是至关重要的,在本实验中需选择合适的催化剂用于非均相催化臭氧氧化实验。在催化剂探究的过程中发现,不同的催化剂催化臭氧氧化降解愈创木酚溶液的效果是有明显区别的。通过γ-Al2O3和AlOOH两种催化剂对愈创木酚溶液进行催化降解以及动力学分析,得到AlOOH催化臭氧氧化降解愈创木酚溶液的效果要明显优于γ-Al2O3。愈创木酚溶液经AlOOH催化臭氧化降解后,愈创木酚的去除率能达到100%,溶液COD去除率能达到89.31%,而γ-Al2O3催化臭氧氧化降解愈创木酚溶液COD去除率仅仅能达到52.7%。催化剂的性能对催化臭氧化效果影响显著,经过γ-A]203和AlOOH两种催化剂性能的测定发现它们的性能虽然区别很大,但它们之间存在着联系,γ-Al2O3是山AlOOH在高温下热解得到的,也就是说AlOOH是γ-Al2O3的前驱体;比表面积分析发现,AlOOH的比表面积要大于γ-Al2O3,大的比表面积有利于臭氧与有机物在其表面接触反应,从而加强催化臭氧氧化的效果。催化臭氧氧化反应中催化剂的引入主要为改善单独臭氧化实验中臭氧的利用率不高、与有机物的反应具有选择性等不足。AlOOH能很好的促进臭氧氧化的反应,愈创木酚溶液经非均相催化臭氧氧化降解后效果要明显优于单独臭氧化效果,且该过程中AlOOH对有机物的吸附作用基本为0。AlOOH催化臭氧氧化降解愈创木酚实验过程受多种因素的影响:臭氧进气流量、初始溶液pH、催化剂投加量、催化剂粒径等,本实验运用正交法对这些影响条件进行了最优化实验,实验结果发现在初始溶液pH为5.4、催化剂投加量为5 g/L、臭氧进气流量为0.51 L/min、臭氧浓度为13.32 mg/L条件下,愈创木酚溶液经40 min反应后,愈创木酚溶液去除率能达到100%, COD去除率能达到89.3%;而催化剂的粒径对愈创木酚的降解效果影响很小,但是经对不同研磨时间的AlOOH进行粒径分析、扫描电镜分析发现研磨时间对粒径的分布有一定的影响。若想把非均相催化臭氧氧化技术应用于工业实际,反映前后AlOOH的性能的测定是至关重要的,通过粒径分析仪、扫描电镜、X射线衍射等对反应前后AlOOH进行了分析,发现催化剂经过反应后会发生些许改变,但是影响并不是很大。AlOOH催化臭氧氧化降解愈创木酚溶液的过程中,溶液由无色变为黄色,判定有中间产物产生,通过液质联用、傅里叶变换红外光谱可对中间产物进行定性,推断出实验过程中出现的两种中间产物。愈创木酚溶液在非均相催化臭氧氧化反应过程中,其结构被破坏,产生了多种中间产物,这些物质继续被氧化才可矿化为CO2和H2O。AlOOH催化臭氧氧化反应是遵循一定机理的,通过紫外可见光谱、液相图谱和添加羟基自由基捕获剂—叔丁醇(TBA)初步探讨了催化臭氧氧化的降解机理,结果表明,在非均相催化臭氧氧化实验中,除了催化剂与臭氧反应产生的单质氧会直接氧化有机物,该反应过程产生的羟基自由基对有机物的作用占据主导地位,且AlOOH表面的羟基基团会促使反应产生更多的羟基自由基。
[Abstract]:Lignin is one of the main pollutants in papermaking wastewater. Guaiacol (GL) is one of the models. Its structure is composed of three parts: benzene ring, hydroxyl group and methoxy. As a kind of organic pollutant, it is difficult to degrade the pollutant by physical method, chemical method, biological method and so on. This experiment selects heterogeneous catalytic ozone. Oxidation technology degrade guaiacol solution. In the experiment of catalytic ozonation, the selection of catalyst is very important. In this experiment, a suitable catalyst is selected for the heterogeneous catalytic ozonation experiment. In the process of catalyst exploration, it is found that different catalysts have been used to catalyze ozonation to degrade guaiacol solution. The effect is obviously different. Through the catalytic degradation and kinetic analysis of guaiacol solution by two kinds of catalysts, gamma -Al2O3 and AlOOH, the effect of AlOOH catalytic ozonization and degradation of guaiacol solution is obviously better than that of gamma -Al2O3. guaiacol solution after AlOOH catalyzed ozonation, and the removal rate of guaiacol can reach 100. %, the removal rate of COD in solution can reach 89.31%, while the COD removal rate of ozonization and degradation of guaiacol by gamma -Al2O3 can only reach the effect of 52.7%. catalyst on the catalytic ozonation. Through the determination of the properties of the two catalysts of gamma -A]203 and AlOOH, they are found to be different, but there is a relationship between them. Gamma -Al2O3 is obtained by pyrolysis of mountain AlOOH at high temperature, that is, AlOOH is a precursor of gamma -Al2O3, and the specific surface area analysis shows that the specific surface area of AlOOH is greater than that of gamma -Al2O3. The larger specific surface area is beneficial to the contact reaction between ozone and organic matter on its surface, thus enhancing the effect of catalytic ozonation oxidation. Catalyst for the catalytic ozonation reaction is used as a catalyst. The introduction is mainly to improve the low utilization of ozone in the separate ozonation experiment and the selectivity of the organic matter..AlOOH can promote the reaction of ozone oxidation well. The effect of the guaiacol solution after the heterogeneous catalytic ozonization is obviously superior to the single ozonation effect, and in this process, the AlOOH has a good effect on the organic matter. The experimental process of 0.AlOOH catalytic ozonation and degradation of guaiacol is influenced by various factors: the air flow rate of ozone, the initial solution pH, the dosage of the catalyst, the particle size of the catalyst and so on. In this experiment, the orthogonal method is used to optimize the conditions of these effects. The experimental results show that the initial solution pH is 5.4, and the catalyst is cast. The addition amount is 5 g/L, the ozonation flow rate is 0.51 L/min and the ozone concentration is 13.32 mg/L. After the 40 min reaction of the guaiacol solution, the removal rate of guaiacol can reach 100% and the COD removal rate can reach 89.3%, while the particle size of the catalyst has little effect on the degradation effect of guaiacol, but the particle size of the guaiacol is very small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small, but the particle size of the guaiacol is small. The diameter analysis and scanning electron microscopy (SEM) analysis found that the grinding time has a certain influence on the distribution of the particle size. If the heterogeneous catalytic ozonation technology is applied to industrial practice, the measurement of the properties of AlOOH before and after the reaction is very important. The particle size analyzer, scanning electron microscope, and X ray diffraction are used to analyze the AlOOH before and after the reaction. The chemical agent will change a little after the reaction, but the effect is not a big.AlOOH catalytic ozonation and degradation of guaiacol solution. The solution changes from colorless to yellow to determine the production of intermediate products. Through the liquid mass spectrometry, the Fu Liye transform infrared spectrum can be used to determine the intermediate products and to deduce the appearance of the experiment. Two intermediate products. In the process of heterogeneous catalytic ozonation, the structure of guaiacol was destroyed and a variety of intermediate products were produced. These substances continue to be oxidized to be mineralized to CO2 and H2O.AlOOH for ozonation, which follows a certain mechanism by ultraviolet visible spectrum, liquid phase atlas and hydroxyl radical addition. The capture agent - TERT butanol (TBA) preliminarily discussed the degradation mechanism of the catalytic ozonation. The results showed that in the heterogeneous catalytic ozonation experiment, the organic matter was oxidized directly by the elemental oxygen produced by the reaction of the catalyst and the ozone reaction. The hydroxyl radicals produced by this reaction process dominate the organic matter, and the surface of the AlOOH surface is on the surface. Hydroxyl groups can induce more hydroxyl radicals in the reaction.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X793

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