光热降解室内空气污染物的研究

发布时间：2018-01-26 12:29

本文关键词： 热催化光催化 Au/ZrO_2 Au/ZrO_2-TiO_2 YS-ZrO_2/TiO_2复合材料 Pt/ZrO_2/TiO_2　出处：《上海师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：现今,随着经济的发展,人们的生活水平逐渐提高,对自身的健康越来越关注。呼吸是人类生存的必须反应之一,因此越来越多的人关注空气的质量问题。可是,现如今,由于工业的发展和人为的破坏,空气的质量每况愈下,因此如何有效的治理空气净化空气,尤其是人们长期生存的室内空气,已经成为了现代人逐渐关注的问题。以TiO_2为代表的半导体光催化剂作为有效的治理不同类型的污染物渐渐得到人们的关注,它无毒无污染廉价可有效利用太阳光,但是它也有一些缺点,如太阳光利用率低,不能有效的捕获和降解低浓度流动的污染气,因此,研究人员提出通过多技术手段即将光催化与其他治理技术相结合,从而弥补和发挥各自的优点。其中,吸附光催化研究的较为广泛,但是吸附剂在吸附的过程中仅仅起到吸附的作用,不能在吸附的同时达到降解的目的,因此这种催化剂在无光的时候仅仅依靠吸附剂的物理吸附作用,很容易达到吸附饱和进而脱附并造成环境的二次污染。热催化氧化技术近年来在低温无光催化氧化气HCHO,CO上已经得到了越来越多的研究,主要是由于其反应可以满足室内的环境的要求并能够达到去除污染物的目的。因此我们提出将热催化技术与光催化技术相结合,有光的条件下,实现光催化,无光的条件下进行热催化,以期可实现全天候的反应。如何选择热催化剂,如何有效的将热催化剂与光催化剂相结合以及如何在实验室中实现对HCHO的模拟降解等都是需要研究和解决的问题,基于此,我们开展了以下几部分工作。(1)Au基催化剂光热去除空气中乙醛的研究先负载贵金属Au于不同的氧化物载体上,通过降解乙醛的研究筛选出ZrO_2为最优的热催化剂载体。通过调变制备Au/ZrO_2过程中溶液的pH以及后期焙烧温度,发现pH=10,焙烧温度为500 0C的Au/ZrO_2对乙醛的吸附降解效果最佳。通过XRD,TEM以及粒径分布统计等的表征,主要是由于这个条件下合成的催化剂Au颗粒尺寸较小而使活性较好。最后通过醇热法合成TiO_2并与热催化剂Au/ZrO_2相结合,发现这种光热催化剂可以很好的实现无光条件下的降解和有光时的光催化。通过这种光热催化剂的制备,可以部分解决吸附光催化的缺点,具有潜在的应用价值。(2)蛋壳型光催化剂的制备及其去除有机污染物的研究通过一步醇热的方法合成了蛋壳型ZrO_2/TiO_2催化剂,合成步骤简单。通过XRD,FESEM,TEM,XPS等表征手段表明该催化剂结构为蛋壳型结构,大小均一。此催化剂表面具有适量的羟基群,可有效捕获光生空穴并生成羟基自由基,ZrO_2/TiO_2之间形成复合物,不会相互覆盖活性位点,并且蛋壳型的催化剂具有大的比表面积即多的活性位点以及对光的多次反射作用,因此对有机物的降解具有良好的作用,具有潜在的室内空气污染物降解的应用价值。(3)光热催化剂的制备及其降解甲醛性能的研究自主成功搭建了甲醛降解及检测一体化的实验装置,通过国标GB/T18204.2-2014酚试剂分光光度法来检测所降解的甲醛的浓度。通过对检测降解一体化装置的调节,最终控制该装置可以稳定运行。通过浸渍还原的方法在蛋壳型催化剂ZrO_2/TiO_2上负载贵金属Pt,对甲醛进行降解,发现该催化剂在室温的条件下,60 min对甲醛的降解效率可达63%。光催化效果不佳,对该装置还需要进一步改进和调节。但是本部分工作对本组降解甲醛的研究奠定了一定的基础。
[Abstract]:Nowadays, with the development of economy, people's living standard gradually improve, increasingly concerned about their own health. Breathing is one of the must respond to human survival, so more and more people pay attention to air quality problems. However, nowadays, with the development of industry and man-made destruction, air quality deterioration, therefore how to effectively the control of air purifying air, especially indoor air long-term survival of people, modern people gradually concern has become. The semiconductor photocatalyst represented by TiO_2 as the effective governance of different types of pollutants and get the attention of people, it has no pollution to cheap can effectively use the sun, but it also has some disadvantages as the sun, light utilization rate is low, pollution gas, can not effectively capture and degradation of low concentration flow so that the researchers put forward by technical means to photocatalysis Combined with other treatment technology, so as to make up and play their respective advantages. The study of adsorption and photocatalysis are widely used, but the adsorbent in the adsorption process plays the role of adsorption, can not reach the purpose of degradation in the adsorption of the catalyst at the same time, when no light only rely on physical adsorption agent, it is easy to reach the adsorption saturation and desorption of two pollution and caused environment. Thermal catalytic oxidation technology in recent years in the low photocatalytic oxidation of gas HCHO, CO has been more and more research, mainly due to the reaction of the indoor environment can meet the requirements and be able to achieve the removal of contaminants. So we put forward the thermal catalytic technology and photocatalytic technology combined with light conditions, light catalysis, heat catalysis under the conditions of no light, which can realize all day long waiting. How to choose the hot catalyst, how to effectively heat and light catalyst catalyst combination and how to realize the simulation of HCHO degradation in the laboratory are needed to study and solve the problem, based on this, we carried out the following work. (1) Au based catalysts for removal of photothermal acetaldehyde in the air to load your Au in different metal oxides, the degradation of acetaldehyde selected ZrO_2 as the catalyst carrier. The optimal heat by changing the preparation process of pH Au/ZrO_2 solution and subsequent calcination temperature, pH=10, adsorption and degradation effect of Au/ZrO_2 calcination temperature of 500 0C of acetaldehyde best. By XRD, TEM and grain the size distribution of statistical characterization is mainly due to the smaller particle size of Au catalyst under the synthesis conditions make good activity. Finally TiO_2 are synthesized by alcohol thermal method and thermal catalyst Au/ ZrO_2 With this catalyst can be found photothermal photocatalytic degradation under the condition of no light and light well. Through this photo catalyst preparation, adsorption and photocatalysis can partly solve the shortcomings, has a potential application value. (2) eggshell type photocatalyst preparation and removal of organic pollutants by one step method for alcohol thermal eggshell type catalyst ZrO_2/TiO_2 synthesis, synthesis of simple steps. Through the XRD, FESEM, TEM, XPS characterization showed that the catalyst structure for shell type structure, uniform size. The surface of the catalyst with proper hydroxyl group, can effectively capture photogenerated holes and generate hydroxyl radicals, complex formation ZrO_2/TiO_2, do not cover each other active site, the catalyst and the eggshell has large surface area that is the active site and the light reflection effect, so the reduction of organic matter The solution has a good effect, has the application value of indoor air pollutants degradation potential. (3) study on Preparation and properties of thermal degradation of formaldehyde catalyst independent success experiments of formaldehyde degradation and detection integrated, to detect the concentration of formaldehyde degradation by GB GB/T18204.2-2014 phenol reagent spectrophotometric method by adjusting. Detection of degradation of the integrated device, the device can control the final stable operation. Through the method of impregnation loading noble metal Pt in eggshell type catalyst ZrO_2/TiO_2, degradation of formaldehyde, the catalyst was found under the condition of room temperature, the degradation efficiency of 63%. photocatalytic effect of 60 min of formaldehyde on the poor, the device also need further improvement and adjustment. But this has laid the foundation for research of this group of partial degradation of formaldehyde.

【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU834.8;X51;O643.36

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