【作者】 姚俊；

【导师】 王潮霞；

【作者基本信息】 江南大学 ， 纺织工程， 2011， 硕士

【摘要】 印染有色废水色度高,排放量大,有机污染物含量高,水质变化大,对环境和人造成严重危害。TiO₂光催化技术利用源源不断的清洁太阳能,深度脱色印染有色废水,可处理多种难降解的污染物。但是TiO₂对太阳光利用率低、空穴和电子复合机率高等不利因素限制其广泛运用。本文制备钡、尿素掺杂TiO₂溶胶和薄膜,提高TiO₂光催化活性,并用于脱色印染有色废水。采用溶胶-凝胶法掺杂碱土金属钡,不加入任何醇类室温下制备钡/TiO₂溶胶。考察不同Ba²⁺掺杂量对溶胶粒径、紫外可见吸收光谱、晶型、红外光谱和光催化活性的影响。结果表明,0.01%Ba²⁺掺杂使得催化剂粒径变小,继续增加则粒径变大。随着Ba²⁺掺杂量的增加,催化剂的吸收边缘波长向长波方向发生移动,对可见光吸收能力增强。XRD谱图表明0.01%Ba²⁺掺杂没有改变TiO₂锐钛矿晶型,但是其特征峰宽化,晶粒尺寸从22.4nm减小至20.1nm。Ba²⁺掺杂使Ti-O键振动吸收峰从485cm-1红移至627cm-1。Ba²⁺掺杂带来催化剂粒径和吸收光谱等性能的变化,提高了TiO₂紫外可见光光催化活性。紫外光下0.05%,可见光下0.01%Ba²⁺掺杂脱色率分别达到89.1%和93.1%。采用旋涂法室温制备钡/TiO₂薄膜,考察旋转速度、涂膜次数、涂膜时间和循环使用次数对薄膜紫外光催化活性的影响。结果表明,涂膜时间30s,旋转速度2500rpm,涂膜3次制备的Ba²⁺/TiO₂薄膜活性较好。循环使用5次后,薄膜光催化活性几乎没有下降。探究钡掺杂对Ba²⁺/TiO₂薄膜的牢固性、亲水性、形貌结构、光透射性能和光催化性能的影响。用自来水冲刷薄膜和透明胶带粘揭薄膜实验表明,薄膜具有很好的牢固性。适量Ba²⁺掺杂减小薄膜接触角,提高薄膜亲水性,从而吸附更多染料分子。薄膜组成颗粒为球形或近球形,分散均匀,0.01%Ba²⁺的掺入能有效抑制颗粒团聚成二次颗粒。0.01%、0.05%Ba²⁺掺杂的TiO₂薄膜对可见紫外光的吸收有所提高。适量钡掺杂可提高薄膜活性,0.01%Ba²⁺掺杂脱色率达86.1%。利用Ba²⁺/TiO₂薄膜脱色染料溶液,考察染料初始浓度、光照强度、光照时间和染料结构对Ba²⁺/TiO₂薄膜光催化活性的影响。结果表明,较高的初始浓度会减小溶液的透光率,降低染液脱色率。光照强度越高活性越好,大于100W继续增加则变化不大。光照时间越长脱色率越高,大于120min则变化不大。Ba²⁺/TiO₂薄膜对实验选取的偶氮和蒽醌染料有很好的脱色效果,其中酸性绿GS脱色率达86.3%。采用溶胶-凝胶法掺杂非金属尿素,不加入任何醇类室温下制备尿素/TiO₂溶胶。考察尿素掺杂量对溶胶粒径、紫外可见吸收光谱、晶型、红外光谱和光催化活性的影响。结果表明,尿素掺杂对溶胶粒径影响不大,平均粒径均在30-40nm之间。尿素掺杂后吸收光波长没有产生明显的红移,但吸收强度有所提高。XRD谱图中没有出现尿素特征峰,但是0.01%尿素掺杂使得TiO₂特征峰宽化。红外谱图表明尿素参与钛酸四正丁酯的水解过程,并与TiO₂形成新的共价键。0.01%尿素掺杂催化剂紫外和可见光活性分别从87.2%提高到95.2%,89.2%提高到92.8%。研究脱色过程中染液的可见吸收光谱发现,染料特征吸收峰逐渐降低至几乎消失,且没有形成新的吸收峰,说明反应过程中没有生成新的有机物质。采用旋涂法室温制备尿素/TiO₂薄膜,研究尿素掺杂对TiO₂薄膜的牢固性、亲水性、形貌结构、光透射性能和光催化性能的影响。尿素/TiO₂薄膜具有很好的牢固性。0.01%尿素掺杂可以提高薄膜亲水性,更加容易吸附溶液中的染料分子,能有效抑制颗粒团聚成二次颗粒。适量尿素掺杂可以提高TiO₂薄膜对紫外可见光的吸收。尿素掺可提高薄膜活性,0.01%尿素使薄膜脱色率从85.6%提高到91.6%。以尼龙6为基体,利用静电纺室温下制备尼龙6/尿素-TiO₂纤维薄膜,其具有极大的比表面积,从而提高光催化活性。对尼龙6/尿素-TiO₂纤维薄膜红外谱图、形貌结构、光催化活性和重复使用性能进行研究。结果表明,红外谱图中分别出现尼龙6和尿素/TiO₂的特征吸收峰。纤维薄膜表面均匀,当混有15%和20%尿素/TiO₂催化剂时,纤维变细至80-200nm之间,比表面积增大,薄膜吸附性能增强。尼龙6/尿素-TiO₂纤维薄膜能吸附5%左右染料,20%催化剂含量时脱色率达93.7%。薄膜重复使用性能良好。纤维薄膜对选取的偶氮和蒽醌染都有很好的脱色效果。通过分析活性红X-3B染液反应前后的红外谱图可以知道,染料结构发生变化,偶氮键断裂以及苯环已经开环降解。钡和尿素掺杂能够有效提高TiO₂光催化活性。旋涂法和静电纺制备的催化剂薄膜均匀平整且牢固性好,可以重复使用。薄膜催化活性高,能够处理多种染料,适用于脱色印染有色废水。更多还原

【Abstract】 Dyeing wastewater from textile industry is large volumes of heavily pollutive wastewaters with high colority and high organic content, containing complicated components, which has caused serious problems to the environment and people. TiO₂ can deeply decolor dyeing wastewater and deal with larger quantities of nonbiodegradable pollutants using a stream of clean solar energy. However, TiO₂ has a low utilization ratio of solar energy. The holes and electrons easily recombine. The negative factors limit the practical application of TiO₂. The paper prepares Ba²⁺ and urea doped TiO₂ sol and films. The catalyst’s photoactivity is improved and expected to decolor the dyeing wastewater.Ba²⁺/TiO₂ sol is prepared by adding alkaline earth Ba²⁺ in absence of alcohol using sol-gel method at room temperature. The effects of amount of doped Ba²⁺ on the particle size, UV/vis absorption spectra, crystal form, FI-IR spectra and photocatalytic activity of the sol are discussed. The results indicate that particle size decreases with adding 0.01%Ba²⁺ then increases as the mass continue to increase. With increased amount of doped Ba²⁺, the absorption wavelength edge shifts to long wave direction, which leads to an increase in optical absorption intensity in the visible-light region. XRD spectra show that 0.01%Ba²⁺ doped doesn’t change the anatase phase of TiO₂, but makes the diffraction peak widen. The crystallite size is reduced from 22.4nm to 20.1nm. Doped Ba²⁺ makes the vibration absorption peaks of Ti-O bond appear a red shift from 485cm-1 to 627cm-1.The changes of TiO₂ properties, such as particle size, absorption spectra, improve UV and visible light photocatalytic activity. The decolorization of 0.05% doped under UV light and 0.01% doped under visible light are 89.1% and 93.1%, respectively.Ba²⁺/TiO₂ film is prepared by spin coating method at room temperature. The effects of amount of doped Ba²⁺, spin speed, film layers, spin time and recycle times on the photocatalytic activity of Ba²⁺/TiO₂ film are discussed. The film spinned 3 times, each time for 30s, in rotation speed of 2500rpm has relatively good photoactivity. The catalytic activity of Ba²⁺/TiO₂ film doesn’t have an obvious decrease after cycle using for 5 times. The effects of doped Ba²⁺ on adhesion, hydrophily, morphology structure, light transmission performance and photocatalytic activity of Ba²⁺/TiO₂ film are investigated. The results indicate that the film is properly adherent proved by tap water erosion test and the scotch tape test. The appropriate amount Ba²⁺ decreases contact angle and improves the hydrophilicity of the film, which is beneficial to adsorb more dye molecules. The film basically contains ball particles and the balls disperse uniformly. 0.01% doped Ba²⁺ can effectively restrain the agglomeration of particles and formation of second particle. 0.01% and 0.05% doped Ba²⁺ also leads to an increase in optical absorption intensity in the ultraviolet light region. The film reduces transmission and increases light absorption with the increase in film layers. The moderate doping can improve the activity of the catalyst and the decolorization of the film with 0.01% Ba²⁺ doped reaches 86.1%. Ba²⁺/TiO₂ film is used to decolor the dye solution. The effects of the initial concentration of dyes, light intensity, irradiation time and dye structure on the photocatalytic activity of the film are investigated. The results indicate that high initial concentration can reduce the light transmittance of the reaction solution, which leads to decrease the decolorization performance. The activity of film presents a trend of rise first to 100W then unchangeableness as light intensity increases. The photodecoloriation increases with the increased irradiation time. Ba²⁺/TiO₂ film has remarkable decolorization ability for both of selected azo and anthraquinone dyes. Among these dyes, the decolorization of acid green GS reaches 86.3%.The urea/TiO₂ sol is prepared by adding nonmetal urea using sol-gel method at room temperature in absence of alcohol. The effects of amount of doped urea on the particle size, UV/vis absorption spectra, crystal form, FI-IR spectra and photocatalytic activity of the sol are investigated. The results indicate that the effect of doped urea on the particle size would be modest. The mean particle size of the sol is around 30-40nm.The doping of urea doesn’t make the absorption threshold wavelength have an obvious red-shift. However, it leads to an increase in optical absorption intensity. The characteristic peak of urea doesn’t appear in the XRD spectra. 0.01% urea doped makes the diffraction peak widen. FI-IR spectra indicate that urea involves in the hydrolysis process of tetrabutyl titanate and forms a new covalent bond with TiO₂. 0.01% doped urea can improve the photoactivity of the catalyst from 87.2% to 95.2%, from 89.2% to 92.8% under UV and visible light, respectively. Absorption spectra changes of the dye solution in the process of decolorization show that the absorption peak rapidly decreases to almost disappear. No new absorption peak and new organic pollutant are generated.The effects of doped urea on adhesion, hydrophily, morphology structure, light transmission performance and photocatalytic activity of urea/TiO₂ film are discussed. The results indicate that the film is properly adherent. 0.01% doped urea improves the hydrophilicity of the film resulting in adsorbing more dye molecules. 0.01% urea can effectively restrain the agglomeration of particles and formation of second particle. The gap between the particles exists. Doped urea also leads to an increase in optical absorption intensity in the ultraviolet and visible light region. The moderate doping can improve the activity of the catalyst. 0.01% urea doped makes the decolorization improves from 85.6% to 91.6%.Nylon 6/urea-TiO₂ fiber film is prepared by electro-spinning method at room temperature based on nylon 6. The film has high specific surface area, which is beneficial to improve the photoactivity. The FI-IR spectra, morphology structure, photocatalytic activity and cycle using performance of the fiber film are discussed. The characteristic absorption peaks of nylon 6 and urea/TiO₂ exist in the FI-IR spectra. The surface of the fiber film is even. When spinning solution contains 15% and 20% urea/TiO₂ catalyst, the fiber becomes thinner between 80nm and 200nm and specific surface area increases, resulting to the strengthen of adsorptive capacity of the fiber film. The film can absorb about 5% dye. The photocatalytic decolorization of the film containing 20% catalyst reaches 93.7%. The film can be reused. Nylon 6/urea-TiO₂ fiber film has remarkable decolorization ability for both of selected azo and anthraquinone dyes. According to the analysis of FI-IR spectra of dye solution before and after the reaction, the dye structure has changed. The azo bond is cleaved and benzene ring is destroyed.Doping Ba²⁺ and urea can effectively improve the photoactivity of TiO₂. The catalyst films prepared by spin coating and electro-spinning methods are even, uniform and adherent. The films with high photocatalytic activity and good reused performance can decolor many kinds of dyes and have potential applicability in treating dyeing wastewater.更多还原