【作者】 李波；

【导师】 李百战； 李娟；

【作者基本信息】 重庆大学 ， 环境科学， 2008， 硕士

【摘要】 人们在对室内进行装饰装修过程中所使用的材料大都含有甲醛、可挥发性有机物等对人体有害的物质,这些物质在室内持续散发,导致室内空气质量（IAQ）严重下降;另外,随着空调系统应用的普及,人们一方面提高建筑物的气密性和热绝缘性,同时降低室内最小新风量标准,就导致了室内有害污染物由于得不到新风稀释而使浓度增大,严重恶化了室内空气品质。如何改善室内空气品质,给人们的生活提供一个健康的室内环境,已经成为人们日益关注的焦点。室内空气污染中人们所关心的焦点当属室内有机污染,主要包括甲醛、苯及其同系物等。目前室内空气有机污染治理的主要有生物方法、物理方法、以及化学方法。光催化技术,是近年来兴起的一种治理室内空气污染的新技术,属于化学方法的一种,它主要是在光催化剂（二氧化钛等）的作用下,使污染物质分解为CO2和H2O等无害物质。该技术反应条件温和、二次污染小、运行成本低,并且可望利用太阳光作为光源,是目前最具发展前景的室内空气净化技术。然而,利用二氧化钛（TiO₂）光催化技术净化室内空气仍处于起步阶段,还有待进一步完善。例如,如何提高TiO₂的量子产率,如何提高其对可见光的利用率,如何改进催化剂的固定技术,以及如何处理中间产物等问题。本文采用改进的Sol-Gel法制备掺铁TiO₂光催化薄膜,通过一组正交试验设计确定了最佳制备工艺参数,然后根据最佳制备工艺参数制备得到了釉面瓷砖和活性炭纤维（ACF）负载的掺铁TiO₂薄膜,并使用X射线衍射（XRD）和扫描电子显微镜（SEM）等技术对薄膜样品的表面形态和晶型等进行了表征分析。本文还通过实验考察了掺铁TiO₂薄膜的光催化活性,讨论了光源、苯初始浓度以及气流组织等因素对光催化活性的影响。最后,本文对TiO₂光催化薄膜的耐用性能进行了研究,包括重复使用性和负载牢固性等。研究结果表明:采用改进的Sol-Gel法制备掺铁TiO₂光催化薄膜时,各工艺参数均对最终的薄膜光催化活性有一定影响,本文通过正交试验确定各工艺参数的最佳取值分别为:PEG掺杂量1.2wt%,Fe³⁺掺杂量0.05wt%,焙烧时间2.0h,焙烧温度500℃。通过XRD和SEM等手段进行表征分析发现,实验制备的TiO₂以锐钛矿和金红石结构为主,粒径分布均匀,平均粒径较小,约为28.5nm。使用掺铁TiO₂薄膜催化降解苯污染物时表现出了良好的光催化活性,若采用产生O3的光源,将有利于增大薄膜光催化效率;光源波长越短,光催化性能越好;光催化活性随光照强度增大呈非线性增加;在一定浓度范围内（浓度较低）,光催化降效率随有机污染物浓度的增加而增大;气流组织对光催化效率也有一定影响,当气流正对光催化薄膜时,有机污染物降解率最高,气流方向与光催化薄膜表面平行时,有机物降解率最低;Fe³⁺的掺杂改性增强了TiO₂对可见光的相应,即使在白炽灯照射下,这种掺铁的TiO₂薄膜仍可表现出一定的光催化活性。ACF担载TiO₂不会对其吸附活性位造成较大影响,相反两者特点相互补充可以提高有机污染物的降解效率,并可避免二次污染。釉面瓷砖和ACF担载TiO₂薄膜具有良好的重复使用性和负载牢固性,耐用性能较好。最后,本文基于ACF/TiO₂材料设计了一种室内空气净化器,认为装修完成初期采用ACF/TiO₂空气净化器进行治理可以取得良好效果,装修完成一段时间后则单靠光催化釉面瓷砖亦可保持室内空气清洁。更多还原

【Abstract】 Most of the materials used in decorating contain formaldehyde, volatile organic compounds and some other things which are bad to people’s health. Those compounds emit continually, and cause the indoor air quality （IAQ） decline heavily; Along with the popularization of air-condition system, on the one hand people enhance the airproof and the heat insulation of buildings, on the other hand they decrease the standard of least fresh air. The consistency of indoor pollutant grows for not been diluted by the fresh air, and make the IAQ deteriorate badly. How to improve the IAQ, and supply a healthy indoor environment, it has become a focus that people pay more and more attentions to.People should be most care about the organic pollution of indoor air, which mainly contains the formaldehyde, benzene and its’homologs. At present, the main ways to treat with the organic pollution of indoor air include biological techniques, physical techniques, and chemical techniques. Photocatalysis is a new chemical technique which comes up these years. Under the effect of photocatalyst （titanium dioxide）, pollutants were decompounded into some harmless substance, like CO2 and H2O. This technique is an indoor air purifying mean which have the best develop future, for its’gentle react condition, little secondary pollution and less cost for run, especially for it is possible to use daylight as the light source.However, using TiO₂-photocatalytic technique to purify indoor air is still beginning. It needs to be improved in some aspects, including how to increase the electron production of TiO₂, how to enhance the efficiency of visible light use,how to improve the method to load catalyst, and how to treat with the mid-productions.The iron-doped TiO₂-photocatalytic film was prepared by the improved Sol-Gel method, and the optimum parameters were confirmed through a group of orthogonal test. The iron-doped TiO₂ film prepared with the optimum parameters was loaded on the faces of enamel tiles and active carbon fiber （ACF）,the surface morphologies and crystalline properties were characterized by X-ray diffraction （XRD） and Scanning electron microscope （SEM）. The photocatalytic activity of the iron-doped TiO₂ film was studied through experiments, and the factors such as light source, initial concentration of benzene, and airflow were discussed. At last, the serviceable abilities of TiO₂-photocatalytic films were investigated, including the renewable ability and the load-fastness.The results indicated that:Each parameter has some influence to the thin film’s phocatalytic activity while the improved Sol-Gel method was adopted to prepare the iron-doped TiO₂ thin film. Through a group of orthogonal test, the optimum parameters are as follows: PEG 1.2 wt%, Fe³⁺ 0.05wt%, calcine time 2.0 hrs, and calcine temperature 500℃.The XRD and SEM tests showed that the prepared TiO₂ was mostly presented to be anatase and rutile. The particle size is about 28.5nm, and distributing equably. The iron-doped TiO₂ thin film displayed well photocatalytic activity when used to deal with the benzene pollutant. Light sources which have the potential to produce O3 conduce to better activity; Shorter wavelength conduces to better photocatalytic activity; The photocatalytic activity shows a non-linear growth trend as the increase of the illumination intensity; in a range of benzene’s low-concentration, The degradation efficiency increases as the initial-concentration grows; And the airflow has some influence to the degradation efficiency-highest when airflow comes face to the thin film, and lowest when airflow comes from back of thin film; Further more, the doped of Fe³⁺ increased the response of TiO₂ to visible-light. Even under the irradiation of incandescence-light, the iron-doped TiO₂ thin film can displays some kind of photocatalytic activity.Loading TiO₂ to the surface of ACF has little affect to the ACF’s absorption active-sites, on the contrary, the traits of ACF and TiO₂ can make up the short of each other and lead to a better degradation efficiency of benzene pollutant, and the secondary pollution can be avoided.Both enamel tiles and ACF loaded TiO₂ thin films have good renewable ability and load-fastness, the serviceable abilities are favorable. At the end of this thesis, an indoor air purify instrument based on the ACF/TiO₂ was designed. It is considered to be feasible that at the beginning after ornamenting, using ACF/TiO₂ air purify instrument have a great effect on dealing with the indoor air pollution, after a period of time, just only the enamel tiles can keep the indoor air cleaning.更多还原