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负载型改性纳米TiO2光催化处理水中染料的研究
Pjotocatalytic Degradation of Dye by Using the Modified Support Nano TiO2
【作者】 蒋宝芳;
【导师】 齐晶瑶;
【作者基本信息】 哈尔滨工业大学 , 市政工程, 2010, 硕士
【摘要】 纳米TiO2光催化剂在水环境染料污染物处理方面应用前景十分广阔。但在水处理过程中使用悬浮型纳米TiO2颗粒存在二次利用后需要分离回收的问题,不但过程繁琐而且需要消耗大量的能量。所以利用一种简单易行的方法使TiO2颗粒负载在载体上制备成一种薄膜,同时使其仍具有较高的光催化效率,是一个十分有前景的研究方向。首先,对用简单的电泳方法,在不锈钢板和玻璃板上负载纳米TiO2颗粒制备的催化剂,进行光催化实验。通过在610nm处测量靛蓝三磺酸钾溶液的吸光度值,作图后比较反应的一级动力学常数k1,发现同一催化剂光催化反应结果的重复性较差,催化剂存在老化现象。进而本实验提出一种再生效果明显的酸洗再生法来解决催化剂的老化问题。另外,理论上只有波长小于388nm的紫外光线,具有足够能量使TiO2催化剂发生光催化反应。自然界的可见光中紫外光线只占不到10%,利用率非常低,而人工产生紫外光线需要消耗巨大能量。通过对负载型N掺杂TiO2催化剂的光催化活性进行研究,发现在可见光的辐射下,N掺杂的TiO2催化剂光催化效率要高于未掺杂的TiO2催化剂;在紫外光的辐射下,两者的催化效率相似。并且通过比较负载在不同载体上的催化剂,发现负载在纸上(AHLSTROM公司生产)的催化剂比不锈钢板和玻璃板上的光催化活性高。同时,本实验把表面分子印迹技术应用到光催化降解水中混合染料(罗丹明B和柠檬黄)的实验中。首先对这种TiO2印迹聚合物进行TEM、XRD、红外(FT-IR)和热重的表征,证明此种聚合物制备成功。它可以对水中的罗丹明B染料选择性降解,提高罗丹明B的降解速率。而非目标污染物柠檬黄的降解速率则明显降低,即此种聚合物能够对水中的罗丹明B进行特异性选择性识别。这种纳米TiO2印迹聚合物制备方法简单易行,在处理水中染料方面具有较好的应用前景。
【Abstract】 It has bright prospect to apply nano-TiO2 photocatalysis technique indegradation of dye pollutants in water environment treatment. However, in thewater treatment process using suspended nano-TiO2 particles poses the problemof separations and reuse, which is not only complicated but also requires a lot ofenergy. So using a simple method to immobilize the TiO2 particles on the carrier,in condition that the TiO2 particles still has high photocatalytic efficiency, is avery promising research direction. In this study we used a simple electrophoresismethod to load nano-TiO2 particles on stainless steel and glass. Throughmeasuring the absorbance of the solution of Potassium Indigo trisulfonate at610nm, drawing out the response, and comparing the kinetic parameters, wefound that the same photocatalytic reaction results are in poor reproducibility andthese catalysts have the problem of aging. To solve this problem, we resorted to asignificant regeneration named acid regeneration.Theoretically ultraviolet light with the wavelength less than 388nm can onlybe used to Photocatalize the titanium dioxide photocatalysis. However in nature,the ultraviolet light take up only 10% of the sunlight. And the artificial ultravioletlight will consume large amounts of energy. This study showed that N-dopedTiO2 can increase the efficiency of visible light. In this study, N-doped TiO2 wasprepared by a simple thermal method, and thin layers of catalyst were depositedby electrophoresis method onto steel substrates. The N-doped TiO2 film showedan enhanced photocatalytic response to the decomposition of the pollutant, undervisible light, in accordance with the photoelectrochemical characterizations. Inthis study, we compared the catalysts on different carriers, and found that thecatalyst on paper (AHLSTROM Company) has a high photocatalytic activity thanthat on the stainless steel panels and glass.At the same time, this study applied the surface molecular imprintingtechnique to reseach the experiments of photocatalytic degradation of mixed dye(Rhodamine B and tartrazine). First of all, we characterized this TiO2-MIP: TEM,XRD, FT-IR and TG, the results of which proved that we successful preparedsuch polymers. It can selectively enhance the degradation rate of rhodamine B. Instead of the target pollutant, the degradation rate of Tartrazine was significantlylower. The method of preparing such nano-TiO2 imprinted polymer is simple,which has good application prospects.
【Key words】 photocatalytic; titanium dioxide; doped with nitrogen; MolecularImprinting Technique;