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自组装FeOOH/TiO2纳米膜光催化降解有机物实验研究

Experiment Research of Self-assembled FeOOH/TiO2 Nano Thin Film Photocatalysis Degradating Organics

【作者】 邵婷

【导师】 孙振亚; 杨红刚;

【作者基本信息】 武汉理工大学 , 环境工程, 2010, 硕士

【摘要】 近年来,新型高效环保材料成为当前治理环境问题的研究热点之一。在多相催化领域,纳米TiO2是典型的光催化剂,广泛应用于有机物降解、杀菌、空气、水的净化等方面。FeOOH具备良好的吸附性能,其光响应的波长在自然光区,能够较好的利用自然光对环境中的有机物进行光催化降解。目前,TiO2的复合材料成为研究热点,纳米Ti02和相对窄的带隙能半导体的复合能减小其禁带宽度,扩展光响应能至可见光范围内,提高光能利用率和复合材料的光催化性能。以石英玻璃片为基体制备纳米FeOOH/TiO2复合材料,一方面能实现薄膜材料的固定,提高光催化剂的利用率;另一方面,两种材料的复合能提高对自然光的利用率。本实验研究了FeOOH/TiO2纳米薄膜的制备、表征及其光催化活性,为实现薄膜制备及应用从小型实验室研究向工业化应用迈进提供了理论依据和指导作用。本文介绍了采用分子自组装方法,以SH为功能团、石英玻璃片为基底,低温液相反应体系中制备纳米FeOOH/TiO2复合薄膜。并以甲基橙为目标物,探讨了不同实验因素对FeOOH/TiO2光催化活性的影响,最后对FeOOH/TiO2薄膜的失活现象与原因以及薄膜的再生方法进行了探讨。论文的主要研究进展如下:(1)通过分子自组装方法制得FeOOH/TiO2薄膜,利用高分辨透射电子显微镜和扫描电子显微镜对该复合薄膜进行表征,最终确定Ti02为锐钛矿结构,FeOOH为针铁矿(a-FeOOH)结构,并判断FeOOH与Ti02为层状-岛状式生长。(2)通过胶带削离、超声以及冲洗实验定性地对比分析了分子自组装法与溶胶-凝胶法制备的FeOOH/TiO2与石英玻璃片间的附着力大小,说明了分子自组装法制备的FeOOH/TiO2与石英玻璃片附着力较强。(3)以甲基橙为目标物,通过几组光催化对比实验,探讨了薄膜制备时间、光源能量、H202、目标物浓度、薄膜复合作用等因素对FeOOH/TiO2的光催化活性的影响。FeOOH/TiO2(其中,TiO2 0.0073g, FeOOH 0.0009g)具有最高光催化活性下的最优实验条件为:制备Ti02的最佳反应时间为4h,甲基橙溶液浓度为1mg/L。可见光下,FeOOH/TiO2光催化lmg/L甲基橙溶液6h,脱色率达99.7%。(4) FeOOH/TiO2薄膜经重复利用20次后,其对甲基橙溶液光催化6h后的脱色率由99.7%降至42.5%,其活性丧失近一半。(5)真空和酸处理均能在一定程度上能实现FeOOH/TiO2的再生。FeOOH/TiO2经真空处理后,活性恢复15.3%;经HCl处理后,活性恢复33.6%。

【Abstract】 Recently, new,high-efficiency, environmental protection materials are becoming one of research focuses. In the area of multiphase photocatalysis, nano TiO2 is a typical photocatalyst, which is widely used in degrading organics, killing baterial, puring air and water. FeOOH, a kind of substance with good adsorptive capacity, on account of its spectral response wavelenghth is at visible district, can photocatalytic degrade organics in environment by well using visilble light. Recently, TiO2 compound materials are researched as focus, because nano TiO2 composited with relatively narrow bandgap semiconductor can diminish forbidden gap of TiO2, extend photoresponses of TiO2 at visible district, enhance its utilization rate to visible light and photocatalysis properties of composite materials. Nano FeOOH/TiO2 compound materials which are prepared on quartz glass, on the one hand, can realize the immobilization of film materials, improve the rate of utilization of photocatalyst; On the other hand, composite of two kinds of materials can enhance the rate of utilization of sunlight. The experiment have studied the preparation, characterization and photocatalysis properities of FeOOH/TiO2 nano thin firm, which provides theory evidence and reference for realizing preparation of thin film from the small laboratory study to industrial application.The paper introduced nano FeOOH/TiO2 compound thin film was prepared from low-temperature aqueous system by molecular self-assembly method, in base of SH functional group and surstrate of quartz glass. Meanwhile, Methyl Orange as target, it discussed some experimental factors affected FeOOH/TiO2 photocatalysis activity. Lastly, it discussed the phenomenon and reason of inactivation when Fe00H/Ti02 compound thin film photocatalysis Methyl Orange, as well as the methods of regeneration for FeOOH/TiO2 compound thin film. The main conclusions of this research was shown as followed:(1) Prepared FeOOH/TiO2 thin film by molecular self-assembly method, characterized FeOOH/TiO2 thin film under TEM and SEM, the result of which was that TiO2, FeOOH were in the form of anatase, goethite(a-FeOOH) and the growing mode between them was layered-island.(2) Qualitative comparison analyse analyse the adhesion between FeOOH/TiO2 thin film, prepared by molecular self-assembly method and sol-gel method, and quartz glass by tape-spalling, ultrasonic and washing methods. The result showed that adhesion between FeOOH/TiO2, prepared by SAMs method, and quartz glass was very strong.(3) Methyl Orange as target, through several phocatalytic comparison experiments, the photocatalysis properties of FeOOH/TiO2 was researched, which was affected by preparation time for film, light energy, H2O2, concentration of object, complexity and substrate material. The best experimental condition in which FeOOH/TiO2 including TiO2 0.0073g, FeOOH 0.0009g was of the highest photocatalysis properties, was that 4h was the best reaction time for preparing TiO2 and the concentration of Methyl Orange aqueous solution was lmg/L. Under the visible light, the decoloration rate of lmg/L Methyl Orange aqueous solution after photocatalysed 6h by FeOOH/TiO2 reached to 99.7%.(4) FeOOH/TiO2 after repeatly used 20 times, the decoloration rate of Methyl Orange solution photocatalysed 6h by FeOOH/TiO2 was fell from 99.7%to 42.5%, the activity of which approximately losted to half.(5) FeOOH/TiO2 could be in a certain extent regenerated vis Vacuum and acid treatment. FeOOH/TiO2 after vacuum treatment, its activity restored by 15.3%. FeOOH/TiO2 after treatment by HCl, its activity restored by 33.6%.

【关键词】 分子自组装FeOOH/TiO2光催化失活再生
【Key words】 SAMsFeOOH/TiO2photocatalysisinactivationregeneration
  • 【分类号】TB383.1;X70
  • 【被引频次】3
  • 【下载频次】233
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