纳米结构化多孔钛的光催化性能

发布时间：2018-01-15 20:05

本文关键词：纳米结构化多孔钛的光催化性能　出处：《西南交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着水污染的日益加重,对工业废水的治理已经成为人们日益关注的一个重大问题。污水中各种有机染料、重金属离子等结构复杂、毒性高、难分解,对生态环境和人类生存都构成了极大的威胁。目前除了适应范围窄且降解作用弱的物理、生化等治理方法,借助二氧化钛尤其是纳米级别的Ti02等半导体进行降解的光催化技术作为一种新兴的化学环保技术,因为其能充分利用光照资源将污染物分解成无毒或毒性较低的物质在水质治理中得到广泛应用。然而随着进一步研究发现,纳米Ti02虽具有较好的光催化能力,但光响应范围较窄,降解速率缓慢。本研究旨在利用不同方式合成高孔隙率的多孔钛,并以此为基底制备Ti02纳米薄膜,探究该材料对水体中常见的有机染料和重金属铬的光催化和吸附性能,为水体中有机和无机污染物的降解提供一种环保高效的新材料,在环境监测和污水治理领域有很大潜力。全文主要包括如下几个方面的内容和结果：①通过添加造孔剂法、泡沫浸渍法和浆料发泡法三种不同的方法制备的多孔钛都具有独特的孔隙结构,其孔隙率和开孔隙率都高达80%以上,具有双峰孔结构,大孔孔径大小为100-500μm之间,小孔孔径几十微米。通过电化学阳极氧化法的HF/H3PO4体系,氧化电压为20V,氧化时间为1h,在三种多孔钛表面均制备了一层管径为100nm左右的Ti02纳米管薄膜,纳米管的生成不受多孔钛孔隙结构的影响,均匀的覆盖在多孔钛的表面,其垂直于多孔钛表面生长。通过不同温度的热处理,改变了样品表面薄膜的晶型结构,制得表面分别为锐钛矿、金红石、以及其混晶结构的样品；②以纳米结构化的多孔钛试样作为光催化剂,考察了光催化剂对几种典型有机染料的降解效果,三种不同试样降解能力发泡法造孔剂法纯钛基底浸渍法,其中发泡法试样2h降解速率达到45%：光催化降解过程中氧化能力来自于羟基自由基,产生的羟基自由基越多,其反应速率越大；考察了不同晶型对甲基橙的降解能力的差异,结果表明锐钛矿和金红石混合晶型光催化活性最强；还对试样降解三种不同染料的能力进行了探究,发现pH影响较大,其中在酸性条件下甲基橙降解的效率要明显高于苯酚,碱性条件下罗丹明B的降解效果则优于甲基橙；将多孔钛试样多次重复利用对甲基橙溶液进行降解,表现出试样良好的重复利用性能；最后暗吸附过程中试样对甲基橙的吸附性能实验进一步证实光催化效果受催化剂对染料分子的吸附能力的影响；③考察了多孔钛试样对Cr(Ⅵ)的吸附性能和光催化还原性能,对各种影响因素进行了探讨,纳米结构化多孔钛对Cr(Ⅵ)的吸附能力受pH和溶液初始浓度影响较大,初始浓度为300mg/L,pH=3的条件下吸附量最大,3h达到吸附平衡,吸附量达到21mg/g；光照条件下,多孔钛对Cr(Ⅵ)有良好的催化还原性能,其降解能力受其吸附性能的影响,在初始浓度为500mg/L, pH=3时具有良好的降解效果,2h降解率可达78%,通过延长时间可以将Cr(Ⅵ)百分百还原为Cr(Ⅲ)。
[Abstract]:With the deterioration of water pollution, treatment of industrial wastewater has become a major issue of increasing concern to the people. All kinds of organic dyes in wastewater, heavy metal ions such as complex structure, high toxicity, difficult to decompose, will constitute a serious threat to the ecological environment and human survival. In addition to narrow and weak physical degradation the biochemical treatment method, especially with TiO2 photocatalytic technology of nanometer level Ti02 semiconductor degradation as a new chemical environmental protection technology, because it can make full use of light pollution resources will be decomposed into non-toxic or low toxic substances are widely used in water treatment. However, with the further the study found that nano Ti02 has better photocatalytic ability, but the light response range is narrow, the degradation rate is slow. The purpose of this study is to synthesize high porosity by different ways Porous titanium, and as a Ti02 nano film fabricated, explore the photocatalytic and adsorption of organic dyes and heavy metal chromium in water of the common material, provide a new material for environmental protection and efficient degradation of organic and inorganic pollutants in water, in environmental monitoring and sewage treatment field has great potential. The main content includes the following aspects: 1, and the results by adding pore forming agent, porous titanium prepared by three different methods of foam impregnation and slurry foaming has unique pore structure, porosity and porosity are as high as 80%, Shuangfeng has the pore structure, pore size is between the size of 100-500 m, the pore diameter of tens of micrometers. The electrochemical anodic oxidation of the HF/H3PO4 system, the oxidation voltage is 20V, oxidation time is 1H, in the three kinds of porous titanium were prepared with a layer of pipe diameter is about 100nm Ti02 Nanotube films, nanotube formation is not affected by the pore structure of the porous titanium surface, uniformly covered with porous titanium, which is perpendicular to the porous titanium surface growth. Through the different heat treatment temperature, change the crystal structure of the sample surface films, prepared surface were anatase, rutile, and mixed the crystal structure of the porous titanium samples; nano structured as photocatalyst, the photocatalytic effect of several typical organic dye degradation was investigated, three kinds of specimens with different degradation ability of foaming pore forming process of pure titanium substrate impregnation method, the foaming method of sample 2H degradation rate of 45%: the oxidation capacity of photocatalytic degradation in the process from the hydroxyl radicals, hydroxyl radicals generated more, the reaction rate is higher; examines the difference of degradation ability of different crystal type of methyl orange, the Octavia anatase and rutile mixed crystal Photocatalytic activity was the strongest; the sample degradation of three kinds of dye ability of inquiry, found that pH affected the efficiency of methyl orange under acidic conditions was higher than that of phenol degradation, the effect of degradation of rhodamine B under alkaline condition is better than that of methyl orange; the porous titanium samples repeatedly used for degradation of methyl orange solution. Show the good performance of sample reuse; finally the dark adsorption experiment, adsorption properties of samples of methyl orange photocatalytic effect was further confirmed by the catalyst of dye molecules adsorption capacity were investigated; the porous titanium samples of Cr (VI) adsorption performance and photocatalytic reduction performance, the influence factors are discussed, nano structured porous titanium Cr (VI) on the adsorption capacity of pH and the initial concentration of the solution affected the initial concentration of 300mg/L, the adsorption capacity under the condition of pH=3 The largest, 3h to reach adsorption equilibrium adsorption capacity can reach 21mg/g; light conditions, porous titanium on Cr (VI) have good catalytic reduction performance, affecting its degradation ability by its adsorption performance, the initial concentration of 500mg/L, pH=3 has good degradation effect, the degradation rate of 2H can reach 78%, by extending the time can be Cr (VI) 100% reduction of Cr (III).

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703;O643.3

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