【作者】 霍鹏伟；

【导师】 闫永胜；

【作者基本信息】 江苏大学 ， 环境工程， 2011， 博士

【摘要】 水污染一直是人们关注最多的环境问题,其污染源主要来自工业废水、生活废水和医药废水。如常见的染料废水具有色度深、毒性大、成分复杂、比较难于处理的特点；医药废水中的抗生素残存所带来的负面效应直接影响到环境生态和人体的健康,越来越引起人们的关注。目前废水处理的手段主要有物理法、化学法、生物化学法等,但众多废水处理技术或存在运行成本高、或带有二次污染等缺点,使得处理效果不能令人满意。半导体光催化降解技术是一种高级氧化技术,是一种最有可能利用自然界太阳光实现清洁去污的环境友好技术,目前已成为人们关注较多的废水处理方法。在众多光催化用半导体材料中TiO2光催化剂具有低廉、无污染、抗光腐蚀等优点被誉为环境友好的污染处理材料,在环保和节能的应用前景受到广泛的关注,其主要应用于废水、废气处理及抗菌、自清洁产品的开发等领域。但是TiO2本身也存在局限性,如其光吸收阈值局限在紫外光区、光量子效率比较低、光催化降解缺乏选择性等。因此,近年来具有可见光响应能力强、光催化活性高、有选择性降解能力的新型光催化剂的开发成为研究的热点。据此我们选取空心微珠(粉煤灰漂珠)为载体,制备TiO2/粉煤灰漂珠负载光催化剂,并对负载光催化剂实施表面敏化修饰和导电聚合物表面修饰,提高光催化剂的光催化效率及对可见光的响应能力；采用分子印迹表面修饰提高光催化剂光降解的特异识别性和选择性。本论文研究主要包括以下三个方面的内容：Ⅰ敏化TiO2/粉煤灰漂珠光催化剂的制备及光催化降解染料废水的研究a.采用溶胶-凝胶技术,以磺化酞菁钴为光敏剂,在低温条件下对二氧化钛溶胶进行敏化,制备了CoPcS/TiO2/粉煤灰漂珠光催化剂；利用电子扫描显微镜(SEM)、X-射线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)和固体紫外漫反射(UV-vis DRS)对催化剂的结构及性能进行了表征；以亚甲基蓝溶液为模拟废水进行光催化降解试验。研究结果表明：低温条件下制备的光敏型TiO2光催化剂中,二氧化钛的晶型主要以混晶态存在(锐钛矿、板钛矿和金红石型)；CoPcS/TiO2/粉煤灰漂珠光催化剂在600-700nm范围内具有较强的吸收,并且在可见光下具有较好的催化活性；可见光照射180min,亚甲基蓝废水的降解率可以达到73.36%。b.采用简单的溶胶凝胶法制备了AgCl光敏剂敏化的TiO2/粉煤灰漂珠光催化剂,并利用X-射线衍射仪(XRD)、电子扫描显微镜(SEM)、热重-差热分析仪(TG-DSC)和固体紫外漫反射(UV-vis DRS)对制备的光催化剂进行了结构及性能表征,同时也考察了光催化剂在可见光下光催化降解罗丹明B废水的性能。结果显示：粉煤灰漂珠表面包所覆的AgCl/TiO2薄层厚度大约为2μm；在可见光照射下,AgCl/TiO2/粉煤灰漂珠光催化剂对罗丹明B废水有较好的降解效果；当掺杂AgCl含量为0.21 g时,可见光光照180min,罗丹明B光降解率可达到94.96%,TOC降解率为20.34%。c.以双氧水为敏化剂对TiO2/粉煤灰漂珠表面进行敏化修饰,制备出表面修饰的复合光催化剂。采用扫描电镜、X-射线衍射、固体紫外漫反射、荧光光谱和X-射线光电能谱对制备的表面修饰光催化剂进行结构和化学成分的表征。在可见光条件下,通过光降解亚甲基蓝废水来考察表面修饰光催化剂的光催化活性。结果表明：H2O2对TiO2/粉煤灰漂珠的表面修饰可以有效的提高对光的吸收性能,在可见光条件下,H2O2表面修饰的TiO2/粉煤灰漂珠光催化对亚甲基蓝的降解率比表面未修饰TiO2/粉煤灰漂珠高42.5%,而且其光催化活性也远高于公认的P25TiO2。Ⅱ导电聚合物修饰TiO2/粉煤灰漂珠的制备及光催化降解抗生素废水研究a.采用光引发聚合功能单体邻苯二胺来敏化修饰TiO2/粉煤灰漂珠,制备出导电聚合物表面修饰的TiO2/粉煤灰漂珠复合光催化剂(POPD/TiO2/粉煤灰漂珠)；通过扫描电镜(SEM)、能量色散光谱(EDS)、比表面积(BET)、X-射线衍射(XRD)、红外光谱(FT-IR)和固体紫外漫反射(UV-vis DRS)等手段对催化剂进行结构及性能表征；在可见光条件下,考察了一系列聚邻苯二胺表面修饰TiO2/粉煤灰漂珠复合光催化剂对抗生素废水的降解性能。结果表明：光诱导聚合物修饰改性后的光催化剂在可见光区具有较好的吸收；POPD/TiO2/粉煤灰漂珠光催化剂的优化制备条件为,pH=3或者pH=4的反应体系,光诱导聚合时间为40 min。在pH=3的反应体系下,紫外光引发聚合40 min制备的改性光催化剂对罗红霉素废水的降解率接近60%,表明以导电聚邻苯二胺作为修饰剂改性的复合光催化剂用于降解抗生素废水是可行的。b.以十六烷基三甲基溴化铵(CTAB)为模板,通过溶胶-凝胶法制备表面多孔道TiO2/粉煤灰漂珠光催化剂；采用光诱导聚合法使聚邻苯二胺(POPD)对多孔道光催化剂表面进行进一步的表面修饰。利用XRD、Raman、SEM、UV-visDRS和FT-IR等对催化剂材料进行表征,催化剂的光催化活性采用在可见光条件下光催化降解环丙沙星抗生素废水的性能来评价。实验结果表明：多孔道结构在光催化剂表面较好地形成；POPD表面修饰后催化剂光催化剂活性有了明显增强。多孔道POPD/TiO2/粉煤灰漂珠光催化降解环丙沙星抗生素废水的降解率可达到71.36%,比未修饰的TiO2/粉煤灰漂珠光催化降解率高出36%,催化剂的多孔道性和导电聚合物POPD修饰可明显提高光催化剂的光催化活性。Ⅲ表面印迹TiO2/粉煤灰漂珠的制备及光催化降解抗生素废水的研究a.采用离子印迹技术制备出Fe2+/Fe3+循环体系的P-OPD/TiO2/粉煤灰漂珠表面离子印迹光催化剂；利用XRD、XPS、SEM、FT-IR、UV-vis DRS对制备的光催化剂进行表征,光催化剂的活性通过在可见光条件下光催化降解环丙沙星抗生素废水进行评价。结果显示：铁离子印迹光催化剂能有效促使Fe2+与Fe3+之间的相互转化,使光生电子与空穴能较好地分离,进而提高了光催化效率。可见光照射60min,铁离子印迹光催化剂光催化降解环丙沙星抗生素废水的降解率可达80%。b.以环丙沙星为模板分子,采用表面分子印迹技术制备出表面分子印迹修饰TiO2/粉煤灰漂珠光催化剂；利用XRD、SEM、FT-IR、UV-vis DRS等对制备的光催化剂进行表征,通过在可见光条件下光催化降解抗生素废水来评价分子印迹光催化剂的选择性和光催化降解光活性。结果表明：表面分子印迹光催化剂可有效实现选择性优先降解模板分子目标物,光催化活性也有明显提高,可见光照射60min其降解效率可达70%,其光催化降解模板分子相对于非印迹光催化剂及实验中的其它非模板分子的选择性系数最大可达3.5299,显示出较好的选择性降解能力。c.以La3+与土霉素的配合物为模板分子,利用分子印迹技术制备出分子/离子型的表面印迹La3+@POPD/TiO2/粉煤灰漂珠光催化剂；采用XRD、SEM、FT-IR、UV-vis DRS对催化剂的晶相、表面结构、形貌及吸光特性进行表征；在可见光条件下考察了分子/离子型表面印迹光催化剂光催化降解抗生素废水的性能。结果显示：表面分子印迹使得催化剂的选择性降解能力得到了有效提高的同时,离子印迹促进了催化剂的光催化活性。可见光照射60 min,光降解土霉素废水的降解效率最高可达76%,相对于离子印迹光催化剂以及其它非模板分子配体,其对模板分子配体光催化降解是选择性系数最大可达4.5146,显示较好的选择性降解能力。更多还原

【Abstract】 Water pollution is always the most considered environmental problem, the industry waste water, living waste water and medical waste water are main polluted source. Especially the dye waste water, which has dark coloure, great toxicity and complex component, is difficult to treat. The medical waste water which contained antibiotic can result in negative influences, and it is directed to influence the environmental zoology and health of the living, so it is more and more attented by us. The treated methods of waste water mainly included physics, chemical, biochemical, et al. The tradiational technology of treated the waste water were always high cost or seconded pollution can not reach the better results. Semiconductor Photocatalysis which belonged advanced oxided technology is one friendly environmentally technology, and may be the ideally realized clear removal pollutant. TiO2 photocatalyst, as one friendly materials, is widely used for treated the waste water and waste gas, and prepared the self-clean products. But TiO2 has limitation, such as the adsorbted light limited UV range, low photons efficiency and lacked selectivity. Thus, the devolopment of strong respond to visible light, high photocatalytic activity and choice new photocatalysts is the hot research.Herein, we chose the fly-ash cenospheres as the carrier and prepared TiO2/fly-ash cenospheres the photocatalyst. Then the loaded catalyst was modified by surface sensitization method which could improve the responds for visible light, and it was enhanced the choice via surface imprinted technology.The work mainly included the following items:I Preparaton of sensitized TiO2/fly-ash cenospheres and degradation of waste dyea. Cobalt Sulfophthalocyanine (CoPcS) sensitized TiO2 Sol samples were prepared through a Sol-Gel method using cobalt sulfophthalocyanine as a sensitizer. Loading and modified floating photocatalyst was prepared by hydrothermal method using fly-ash cenospheres as a carrier. The properties of the samples were characterized by Scanning electron microscopy(SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectrum (DRS). Photocatalytic activity was studied by degrading waste water of methylene blue under visible light. The results indicate that the fly-ash cenospheres are covered by modified TiO2 film which composed of the anatase, brookite and rutile mischcrystal phase. CoPcS/TiO2/fly-ash cenospheres samples have good catalytic activity under visible light, and have strong absorbency during 600-700nm. The sensitization of CoPcS can enhance visible light catalytic activity of TiO2/Fly-ash cenospheres. The degradation rate of methylene blue reaches 73.36% in 180 min under the visible light illumination. But too much CoPcS can decrease its catalytic activity.b. AgCl/TiO2/fly-ash cenospheres photocatalysts were prepared by a simple sol-gel method. The catalysts were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), thermo gravimetric analysis-differential scanning calorimeter (TG-DSC), and UV-vis diffuse reflection spectrum (UV-vis DRS). The results show that the fly-ash cenospheres are coated with about 2μm thickness of AgCl/TiO2 nano-composite films. The fly-ash cenospheres loaded the films of AgCl/TiO2 photocatalysts exhibit high visible-light-induced photocatalytic activity for the decomposition of Rhodamine B waste water. When the photocatalyst contained the dosage of 0.21 g AgCl, the photo-degradation rate could reach 94.96% in 180 min under visible light irradiation, and removal rate of TOC could reach 20.34% in the same condition.c. The TiO2/fly-ash cenospheres were prepared via sol-gel method, and the surface of TiO2/fly-ash cenospheres was further modified by hydrogen peroxide (H2O2). Scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) were applied to characterize structure, performance and chemical composition of as-prepared samples. The photocatalytic activity of as-prepared samples was evaluated by degradation of methylene blue under visible light irradiation. The results indicate that the modified phototcatalyst of TiO2/fly-ash cenospheres is effectively improved the absorption of light. The photocatalytic degradation of methylene blue is enhanced under visible light irradiation, which the degradation rate is higher 42.5%than the untreated TiO2/fly-ash cenospheres with H2O2. Moreover, the simple way to modified TiO2/fly-ash cenospheres and enhancing the photocatalytic activity is better for practical application.ⅡPreparation of modified photocatalyst via conductive polymer and degradation of antibiotic waste watera. A series of Poly-o-phenylenediamine/TiO2/fly-ash cenospheres (POPD /TiO2/fly-ash cenospheres) composites have been prepared from o-phenylenediamine and TiO2/fly-ash cenospheres under various polymerization conditions. The properties of the samples were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy (EDS), specific surface area (BET), X-ray diffraction (XRD), fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectrum (UV-vis DRS). Photocatalytic activity was studied by degradation of antibiotics waste water under visible light. The results indicate that the photo-induced method is viable for preparing modified photocatalysts, and the modified photocatalysts have good absorption in visible light range. The photocatalysts of POPD/TiO2/fly-ash cenospheres which have good performance are prepared at pH=3 and pH=4, and the polymerized time around 40 min. When the photocatalysts are prepared under the conditions of pH=3 and polymerized time 40 min, the degradation rate of roxithromycin waste water could reach near 60%, and it indicates that the way of POPD modified TiO2/fly-ash cenospheres to degrade the antibiotics waste water is viable.b. Porous-TiO2/fly-ash cenospheres were prepared via sol-gel with a traditionary surfactant hexadcetyltrimethylammonium bromide (CTAB) as template. The as-prepared porous materials were further modified by the poly o-phenylenediamine (POPD) with photo-induce method. The as-prepared photocatalysts were characterized by XRD, Raman, SEM, UV-vis DRS, FT-IR analyses. The photocatalytic activity was studied via degradation of ciprofloxacin antibiotic waste water under visible light irradiation. The results indicate that porous materials is well formed, the photocatalytic activity of photocatalyst is enhanced with modified POPD. The degradation rate of POPD/porous-TiO2/fly-ash cenospheres could reach 71.36%which improved near 36%than the degradation rate of TiO2/fly-ash cenospheres. It clearly shows that the properties of porous and POPD modification could effectively increase the photocatalytic activity.ⅢPreparation surface imprinted photocatalysts and degradation of antibiotic waste watera. Fe2+/Fe3+@P-OPD/TiO2/fly-ash cenospheres photocatalysts has been successfully prepared by ions imprinting technology. The as-prepared ions imprinting photocatalysts have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and Fourier transform infrared (FT-IR). The photocatalytic activity of the samples was studied by the degradation of ciprofloxacin antibiotics waste water under visible light irradiation. The results showed that the iron ions imprinting photocatalysts could effectively promote the mutual transformationbetween Fe2+and Fe3+, increased the separation rate of photoelectrons and holes in the cycling system, and so improved the photocatalytic activity of photodegradation system on the ciprofloxacin antibiotics.. The photodegradation rate could reach 80 % in 50 min under visible light irradiation. According to our experimental results, a mechanism of preparation and photodegradation system of ions imprinting photocatalyst was also proposed.b. The surface molecular imprinted photocatalyst of TiO2/fly-ash cenospheres was prepared by molecular imprinted technology with ciprofloxacin as the template. The imprinted photocatalyst was further characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and Fourier transform infrared (FT-IR). The preferential choice and activity of imprinted photocatalyst was evaluated by degradation of antiobic waste water. The results indicate that the surface imprinted photocatalyst could effectively preferential degradation of template molecular and enhance the photocatalytic activity. The degradation rate of molecular could reach 70% in 60 min under visible light irradiation. The degradation coefficient of relatively selectivity could reach 3.5299 compared with the tetracycline. The degradation intermediate product of ciprofloxacin was further discussed.c. The molecular/ion surface imprinted TiO2/fly-ash cenospheres photocatalyst was prepared by molecular imprinted technology with La3+and oxytetracycline. The phase, surface structure and light absorption of as-prepared photocatalyst were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and Fourier transform infrared (FT-IR). The preferential choice and activity of imprinted photocatalyst was evaluated by degradation of antibiotic waste water. The results indicate that molecular/ion surface imprinted photocatalyst could effectively preferential degradation of template molecular and enhance the photocatalytic activity. The degradation rate of molecular could reach 76% in 60 min under visible light irradiation. The degradation coefficient of relatively selectivity could reach 4.5146 compared with the ciprofloxacin.更多还原