低维钛基纳米材料的水热合成及其在染料废水处理中的应用

发布时间：2018-12-14 06:31

【摘要】：以水热法为基础制备二氧化钛或钛酸盐等低维钛基纳米材料由于具有特殊的层状结构和较大的比表面积,近二十年来一直是纳米科学的研究热点之一。围绕低维钛基纳米材料的形貌调控、光催化性能的提高以及在其他领域的潜在应用,科学家们做了大量的工作。但就目前的状况而言,对于低维钛基纳米材料的研究仍有很大的空间,通过进一步的深入研究,我们相信低维钛基纳米材料具有广阔的应用前景。本论文围绕低维钛基纳米材料这一主题,从一维钛基纳米管的结构、光催化性能的改善,以二维钛基纳米片为壳层的层级结构的构造及调控方面进行了深入研究。利用P25为原料,在10M的NaOH溶液中通过水热法制备了一维钛基纳米管,通过控制在0.1 M盐酸中Na+被H+离子交换的量,得到了不同质子化程度的钛基纳米管。通过ICP检测质子化程度(H+/Na+)分别为0,0.2,0.5,1.0,2.0,5.0的样品中剩余Na+的含量分别为4.996%,2.914%,0.668%,0.192%,0.061%,0.052%。部分质子化钛基纳米管中Na+的在稳定管状结构方面起到重要作用,随着质子化程度的提高,经过450℃热处理的样品的形貌由管状向棒状转化。研究了一系列部分质子化钛基纳米管的形貌、组分及比表面积对甲基橙在紫外光下的降解能力。利用钛酸四丁酯作为原料,通过溶胶凝胶法并热处理制备了稀土元素Gd掺杂的二氧化钛纳米颗粒(掺杂量Gd/Ti=0,0.1,0.2,0.5,1.0,2.0,5.0)。通过XRD表征,未掺杂的二氧化钛纳米颗粒在700℃热处理后呈现金红石相,随着Gd掺杂量的增加,抑制二氧化钛纳米颗粒的结晶,使Gd掺杂的二氧化钛纳米颗粒的组成由金红石逐渐向锐钛矿转变,同时颗粒尺寸逐渐变小。研究了Gd掺杂的二氧化钛纳米颗粒随着组分和结晶度的变化对甲基橙的光催化降解的性能变化规律。利用溶胶凝胶法制备的Gd掺杂的二氧化钛纳米颗粒为原料,通过在10 M的NaOH溶液中150℃水热反应24 h并经过后处理过程制备了Gd掺杂的二氧化钛纳米管。由ICP测得的标称掺杂量分别为0.1%,0.2%,0.5%,1.0%,2.0%,5.0%的Gd掺杂的二氧化钛纳米管中实际的Gd掺杂量分别为0.085%,0.131%,0.280%,0.706%,1.735%和4.715%。研究了Gd掺杂量对二氧化钛纳米管的组分、结构、光学性质及光催化降解甲基橙能力的影响。同时,研究了甲基橙初始浓度对最佳催化剂的降解能力的影响。以三氯化铁为原料利用溶剂热法制备了Fe3O4球,球的直径约为198 nm,由约8 nm的小颗粒组成。该Fe3O4球在带有负电荷的聚苯乙烯磺酸-马来酸共聚物钠盐分子链形成的空间中自组装而成,具有良好的水溶性和分散性。利用Stober法在Fe3O4表面包覆了一层SiO2,通过TEM、XRD、FTIR等手段证明了SiO2层的存在,研究发现正硅酸乙酯的加入量对壳层厚度产生明显影响,通过分次加入的方式可以减少产物的团聚。以Fe3O4@SiO2为核心,使用钛酸异丙酯为原料,在表面包覆了一层无定型二氧化钛,形成Fe3O4@SiO2@AT三层结构,二氧化钛与内层的SiO2层通过Ti-O-Si键的形式紧密结合。通过对Fe3O4@SiO2@AT进行水热反应,制备了Fe3O4@titanate层级结构,并研究了水热温度和碱度对产物形貌的影响,得到了最佳的反应条件。Fe3O4@titanate花状结构保留了良好的超顺磁性,饱和磁化率达到39.6 emu/g,在吸附实验中对亚甲基蓝的吸附率超过85%,在两次重新活化后对亚甲基蓝的吸附率仍然超过80%,是作为可回收吸附剂的理想材料。同时按照相似的思路,以Fe3O4@SiO2为核心,利用十六烷基三甲基溴化铵作为模板剂,制备了表面介孔的Fe3O4@SiO2三层结构。为了得到形貌均匀、分散良好的Fe3O4@SiO2@mSiO2结构,研究了各反应参数如反应时间、正硅酸乙酯用量、氨水用量等对产物形貌和结构的影响。
[Abstract]:The preparation of the low-dimensional titanium-based nano-materials such as titanium dioxide or titanate based on the hydrothermal method has been one of the hot spots of the nano-science for nearly two decades due to the special layered structure and the larger specific surface area. The scientists have done a lot of work around the appearance and control of the low-dimensional titanium-based nano-materials, the improvement of the photocatalytic performance and the potential applications in other fields. However, for the present situation, there is still a lot of space for the research of the low-dimensional titanium-based nano-materials. Through further research, we believe that the low-dimensional titanium-based nano-material has a wide application prospect. In this paper, the structure of the one-dimensional titanium-based nano-material and the improvement of the photocatalytic property of the low-dimensional titanium-based nano-material are studied in this paper. One-dimensional titanium-based nanotubes were prepared by hydrothermal method in the NaOH solution of 10M using P25 as the raw material, and the titanium-based nanotubes with different protonation were obtained by controlling the amount of Na + in 0.1 M hydrochloric acid to H + ion exchange. The contents of the remaining Na + in the samples were respectively 4.996%, 2.914%, 0.668%, 0.192%, 0.061%, and 0.052%, respectively, by ICP. The content of Na + in the partially protonic titanium-based nanotubes plays an important role in the stabilization of the tubular structure. With the increase of the degree of protonation, the morphology of the sample subjected to heat treatment at 450.d egree. C. is transformed from the tube to the rod. The morphology, composition and specific surface area of a series of partially protonic titanium-based nanotubes were studied. The rare-earth-earth Gd-doped TiO _ 2 nanoparticles were prepared by sol-gel method and heat treatment (Gd/ Ti = 0, 0.1, 0.2, 0.5, 1.0, 2.0, 5.0). By XRD, the unadulterated titanium dioxide nano-particles show a rutile phase after heat treatment at 700 DEG C, the crystal of the titanium dioxide nano-particles is inhibited with the increase of the Gd doping amount, the composition of the Gd-doped titanium dioxide nano-particles is gradually changed from the rutile to the anatase, while the particle size is gradually reduced. The effect of Gd-doped TiO _ 2 nanoparticles on the photocatalytic degradation of methyl orange with the change of composition and crystallinity was studied. The Gd-doped titanium dioxide nano-particles prepared by the sol-gel method are used as raw materials, and the Gd-doped titanium dioxide nano-tubes are prepared by hydrothermal reaction at the temperature of 150 DEG C for 24 hours in a 10-M NaOH solution and after the Gd-doped titanium dioxide nano-particles are subjected to a post-treatment process. The actual Gd-doping in the titanium dioxide nanotubes doped with Gd-doped titanium dioxide was 0. 085%, 0. 131%, 0. 280%, 0. 706%, 1. 735% and 4.715%, respectively, by ICP. The effect of Gd doping on the components, structure, optical properties and photocatalytic degradation of methyl orange in titanium dioxide nanotubes was studied. The effect of the initial concentration of methyl orange on the degradation ability of the best catalyst was also studied. The Fe 3O 4 ball was prepared by the solvent-heat method with ferric chloride as the raw material. The diameter of the ball was about 198 nm, and it was composed of small particles of about 8 nm. The Fe3O4 ball is self-assembled in a space formed by a polystyrene sulfonic acid-maleic acid copolymer sodium salt molecular chain with a negative charge, and has good water solubility and dispersibility. A layer of SiO2 was coated on the surface of the Fe3O4 by the Stover method, and the presence of the SiO2 layer was demonstrated by means of TEM, XRD and FTIR. It was found that the addition of ethyl orthosilicate had a significant effect on the thickness of the shell, and the agglomeration of the product can be reduced by the way of sub-addition. using the Fe3O4@SiO2 as the core, a layer of amorphous titanium dioxide is coated on the surface to form a Fe3O4@SiO2 @ AT three-layer structure, and the SiO2 layer of the titanium dioxide and the inner layer is tightly combined by the form of a Ti-O-Si bond. The Fe3O4@titanate-level structure was prepared by hydrothermal reaction to the Fe3O4@SiO2 @ AT, and the effect of the hydrothermal temperature and the alkalinity on the morphology of the product was studied. The best reaction condition was obtained. The .Fe3O4@titanate-like structure had a good superparamagnetism and the saturation magnetic susceptibility reached 39.6emu/ g. The adsorption rate of methylene blue is more than 85% in the adsorption experiment, and the adsorption rate of methylene blue after two re-activation is still more than 80%, which is an ideal material for the recovery of the adsorbent. At the same time, according to the similar thought, using the Fe3O4@SiO2 as the core and using the hexadecyl trimethyl bromide as the template agent, the Fe3O4@SiO2 three-layer structure of the surface dielectric hole is prepared. In order to obtain the Fe3O4@SiO2 @ mSiO2 structure with uniform morphology and good dispersion, the effects of reaction parameters such as reaction time, amount of ethyl orthosilicate and the amount of ammonia water on the morphology and structure of the product were studied.
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X788;TB383.1

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