【作者】 顾松球；

【导师】 刘建华；

【作者基本信息】 大连海事大学 ， 环境工程， 2008， 硕士

【摘要】 随着资源的过度利用和大自然的严重污染,生态环境遭受了严重的破坏。人们迫切需要开发能够经济有效地利用能源并具有不污染环境的功能意识材料。纳米TiO₂正是这种具有净化环境功能的绿色材料,它可完成环境净化、能源再生、能源贮备、不污染环境等多项功效。纳米TiO₂可通过多种技术制备,且日臻成熟,但仍普遍存在设备复杂、条件难控、产业化困难等问题。纳米TiO₂具有无毒、催化效率高、性能稳定、价廉等突出特点,以及在光催化氧化处理废水及净化空气中的应用,使它已成为目前光催化研究领域中最活跃的方向之一。焦化废水是冶金工业废水中的一类,其危害大、处理困难,已成为我国目前重点控制的废水之一。光催化氧化技术是近年来发展起来的一种新型水处理技术,因高效、无二次污染,且具有可直接利用太阳能的潜力,而受到各国学者的关注。纳米TiO₂具有优异的光催化活性,它能将环境中存在的微量有机物降解为无污染的无机物,还能杀死细菌病毒,因此具有广泛的应用前景。但是,纳米TiO₂光催化剂须依赖于紫外光,对太阳光的利用率低,因而限制了它的应用。为了提高纳米TiO₂在可见光区的光催化活性,充分利用太阳光,必须对其进行改性。以硫脲为掺杂剂制备了均匀分散的硫掺杂纳米TiO₂光催化剂,探讨了硫掺杂对纳米TiO₂的晶相结构、原子价态及催化剂表面状态的影响,并对其掺杂机理进行了研究。结果认为在高温热处理过程中,由于微量的硫以S⁴⁺进入TiO₂的晶格中取代了部分Ti⁴⁺而导致局部变形,导致TiO₂的价带和导带之间的带隙变窄,从而提高了TiO₂的可见光的光谱响应。本文用硫掺杂纳米TiO₂作为光催化剂催化降解焦化废水,实验结果表明经450℃热处理的硫掺杂纳米TiO₂薄膜能很好地降解焦化废水中的有机物,处理后水中的COD与NH₃-N等指标均达到排放要求。更多还原

【Abstract】 With the excessive exploitation of natural resources and grave Pollution of environment,the deterioration of ecological environment becomes more and more serious.It is urgent to develop eco-materials,which use economically energy and have no harm to environment.With its renewal ability and storability of energy and friendliness of environment,nano-semieonductor TiO₂ is the very novel green purificant, Now its relevant study becomes the focus of the field of photocatalysis,especially in wastewater treatment.Although nano-TiO₂ Powders can be obtained by many methods such as Sol-Gel Process,chemical deposition,these methods are complex in equipments,strict in conditions of preparation..As a result,it is difficult to realize its commercialization.The pertinent research work has been carried out follows.In environment protection field,it is one of key controlling objects to decontaminate wastewater coking,which poses great harm to environment and become a serious problem in metallurgy industry.Photocatalytic oxidation of water contaminants is a new method for wastewater treatment.It is widely and deeply studied by researchers for its high degradation efficiency,none secondary pollution caused and the potential of utilization of solar energy.Nano-titanium dioxide,used as a photocatalyst can degrade the trace organic compounds to non-toxic substances and can kill bacteria and virus,therefore,it is of great value in the practical applications. However,it suffered from the disadvantages that the nano-titanium dioxide cannot show the excellent photocatalytic activity until irradiated with UV light and the utilization of the solar rays is too limited and ineffective,which hinders its widespread applications to a great extent.In order to improve the photocatalytic activity and make full use of the solar rays,the nano-titanium dioxide must be modified. S-doped uniform TiO₂ photocatalysts were prepared using thiourea as the doping agent for the first time in China.The influence of sulfur doping on the crystal structure of nano-TiO₂,the energy level state and the surface state were investigated.The doping mechanism was also discussed.The results of photocatalytic degradation coking-plant wasterwater demonstrated that the S-doped uniform TiO₂ exhibited the highest photocatalytic activity when calcined at 450℃for 4 hours.The COD and NH₃-N are accord to water’s quality.更多还原