活性炭负载二氧化钛复合材料的制备表征及对活性黄印染废水处理研究

发布时间：2018-03-26 09:39

本文选题：紫外光照　切入点：二氧化钛/活性碳　出处：《华中科技大学》2015年硕士论文

【摘要】：印染废水具有组成成分复杂,难降解物质多,浓度较大,处理难度大等特点,是环境污染的主要来源之一。光催化技术能有效解决环境问题,其中二氧化钛光催化剂具有光催化活性高,化学稳定性良好,并且廉价无毒等优点,因而被广泛应用于污废水处理、有机物降解等领域。然而二氧化钛可利用光谱范围窄,易团聚难分离及重复利用,大大增加了处理成本。因此,研究具有高催化活性的新型TiO2光催化剂,探讨其对印染废水的光催化降解效果得到研究人员的重点关注。在减轻有机物污染还是保障人类生命安全都具有十分重要的意义。本文在此背景下,采用溶胶-凝胶法制备出具有较高光催化活性的复合光催化剂,通过相关技术手段对其进行分析表征,并将其应用于活性黄模拟印染废水的处理研究,具体研究内容和结果如下:首先,本文以椰壳活性炭为载体,采用溶胶-凝胶法制备活性炭负载二氧化钛复合光催化剂,通过扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱、热重/差热综合分析仪、紫外-可见漫反射、X射线光电子能谱等分析手段对负载型复合光催化剂的表面形貌、晶态结构、表面官能团、价态及光学性能进行表征。结果表明该法制备出的复合光催化剂具有较高的光催化性能,二氧化钛颗粒较为均匀地负载于椰壳活性炭表面。复合光催化剂的光催化活性受制备时煅烧温度的影响,随着煅烧温度的升高,锐钛矿型二氧化钛晶型更为完善。并且负载后的二氧化钛在可见光区的吸收强度比纯二氧化钛有明显提升。其次,本文将复合光催化剂应用于活性黄模拟印染废水的光催化处理中,并就复合光催化剂的投加量、印染废水的pH值、活性黄溶液的初始浓度等因素对光催化效果的影响进行研究,对复合光催化剂的光催化活性进行评价。实验结果表明:活性炭与二氧化钛之间存在某种协同机制,体系具有较高的光催化活性。在一定范围内,XRG的降解率随Ti O2/AC投加量的增加而升高,当其投加量超过最佳投量2.0g/L时,产生屏蔽效应;酸性条件下有利于XRG的光降解;随着XRG初始浓度的升高,其降解率逐渐降低;双氧水对光降解效果的影响具有两面性;而离子强度的增加有利于光反应的进行。本文的研究成果为优化二氧化钛光催化剂及其光催化降解机理的研究提供了有价值的借鉴,为进一步研究印染废水的处理提供了新的思路和科学依据。
[Abstract]:Printing and dyeing wastewater is one of the main sources of environmental pollution due to its complex composition, high concentration, high concentration and difficulty in treatment. Photocatalytic technology can effectively solve environmental problems. Among them, titanium dioxide photocatalyst has the advantages of high photocatalytic activity, good chemical stability, cheap and non-toxic, so it is widely used in wastewater treatment, organic degradation and other fields. It is easy to agglomeration and difficult to separate and reuse, which greatly increases the cost of treatment. Therefore, a new type of TiO2 photocatalyst with high catalytic activity is studied. The study on photocatalytic degradation of printing and dyeing wastewater has attracted the attention of researchers. It is of great significance in reducing organic pollution and ensuring the safety of human life. The composite photocatalyst with high photocatalytic activity was prepared by sol-gel method. The composite photocatalyst was analyzed and characterized by related technology and applied to the treatment of reactive yellow simulated printing and dyeing wastewater. The specific research contents and results are as follows: firstly, the active carbon supported titanium dioxide composite photocatalyst was prepared by sol-gel method with coconut shell activated carbon as the carrier, and X-ray diffractometer was used by scanning electron microscope. Fourier transform infrared spectroscopy (FTIR), thermogravimetric / differential thermal analysis (TG-DTA), UV-Vis diffuse reflectance X-ray photoelectron spectroscopy (UV-Vis) and so on, were used to analyze the surface morphology, crystal structure and surface functional groups of the supported composite photocatalysts. The results show that the composite photocatalyst prepared by this method has high photocatalytic performance. The photocatalytic activity of the composite photocatalyst is affected by the calcination temperature during preparation, and with the increase of calcination temperature, the TIO _ 2 particles are loaded on the surface of the coconut shell activated carbon evenly, the photocatalytic activity of the composite photocatalyst is affected by the calcination temperature. Anatase titanium dioxide crystal form is more perfect, and the absorption intensity of loaded titanium dioxide in visible region is obviously higher than that of pure titanium dioxide. Secondly, In this paper, the composite photocatalyst was applied to the photocatalytic treatment of reactive yellow simulated printing and dyeing wastewater. The effects of the dosage of composite photocatalyst, the pH value of printing and dyeing wastewater and the initial concentration of active yellow solution on the photocatalytic effect were studied. The photocatalytic activity of the composite photocatalyst was evaluated. The experimental results showed that there was a synergistic mechanism between activated carbon and titanium dioxide. The system has higher photocatalytic activity. The degradation rate of XRG increases with the increase of Ti O2/AC dosage in a certain range. When the dosage exceeds the optimal dosage of 2.0g/L, the effect of shielding is produced, and the degradation rate of XRG is favorable to the photodegradation of XRG under acidic conditions. With the increase of initial concentration of XRG, the degradation rate decreases gradually, and the effect of hydrogen peroxide on photodegradation is dual. The increase of ionic strength is beneficial to the photoreaction. The research results in this paper provide a valuable reference for optimizing the study of titanium dioxide photocatalyst and its photocatalytic degradation mechanism. It provides a new idea and scientific basis for further research on the treatment of printing and dyeing wastewater.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X791;TB33

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