粉煤灰沸石分子筛负载二氧化钛的制备及光催化性能的研究

发布时间：2018-04-15 16:47

  本文选题：粉煤灰 + 沸石分子筛　； 参考：《北京交通大学》2015年硕士论文

【摘要】：粉煤灰作为众多发电厂的燃煤锅炉所排放出的废渣,也是非常宝贵的可利用资源,而使用粉煤灰作为主要原料,合成沸石分子筛,就成为了粉煤灰应用的一个很重要的方面。粉煤灰沸石分子筛以它所具有的良好的吸附性、分离作用以及在离子交换、催化等方面的重要应用而广泛受人们所青睐。以二氧化钛为主的光催化处理技术是一种具有高处理率、低能消耗、无二次污染、工艺设备简单的新型废水处理技术,但由于二氧化钛的颗粒较小,难回收,容易形成二次污染,用沸石分子筛做载体就可以很好的将其固定起来。本论文重点研究两个方面的内容,一是如何以粉煤灰作为主要原材料制备沸石分子筛,二是如何将制备好的沸石分子筛与二氧化钛有效负载。 首先所采用的制备沸石分子筛的方法是碱熔融水热法,以预处理过的粉煤灰作为主要原材料,加碱熔融粉煤灰合成沸石分子筛。通过实验来研究不同灰碱比、不同焙烧温度及时间、不同水热晶化温度及时间等因素对合成沸石分子筛影响。利用X射线衍射(XRD)、扫描电镜(SEM)、比表面积测试(BET)等方法表征产物的形貌、物相、比表面积等并计算产率。测试结果表明,当NaOH:粉煤灰：Na2CO3为1.2：1：0.3,煅烧温度是550℃,煅烧时间是70min,晶化温度是90℃,晶化时间是24小时,所制得沸石分子筛主要是Na-X型,BET测定比表面积是90.123m2/g,产率为56.9%。 以沸石分子筛作为载体来负载二氧化钛,根据所使用的原料不同总体采用了三种实验方案。以乙醇和钛酸四丁酯为主要原料制备负载型TiO2/沸石分子筛并讨论分子筛加入的先后顺序对实验结果的影响,结果表明用原位溶胶凝胶法负载二氧化钛所得产品形貌最佳,比表面积可达145.782m2/g,降解甲基橙的光催化率可高达50.2%；以钛酸四丁酯和异丙醇为主要原料制备负载型TiO2/沸石分子筛并讨论负载量的多少对实验结果的影响,结果表明40%TiO2/沸石分子筛比表面积最大,可达151.452m2/g,降解甲基橙的光催化率可高达59.8%；以异丙醇钛和异丙醇作为主要原料制备负载型TiO2/沸石分子筛并讨论焙烧温度对产品的影响,结果表明500℃的焙烧温度最佳,产品比表面积可达149.3m2/g,降解甲基橙的光催化率可达51.2%。对比这三种方案,本论文里所采用钛酸四丁酯与异丙醇制得的产品比表面积最大,光催化性能最好。
[Abstract]:Fly ash, as a waste residue discharged from coal-fired boilers in many power plants, is also a valuable available resource, and the use of fly ash as the main raw material to synthesize zeolite molecular sieve has become a very important aspect of the application of fly ash.Fly ash zeolites have been widely used in many fields such as adsorption, separation, ion exchange, catalysis and so on.The photocatalytic treatment technology based on titanium dioxide is a new type of wastewater treatment technology with high treatment rate, low energy consumption, no secondary pollution and simple process equipment. However, it is difficult to recover titanium dioxide because of its small particle size.It is easy to form secondary pollution and can be well immobilized with zeolite molecular sieve as carrier.This thesis focuses on two aspects: one is how to use fly ash as the main raw material to prepare zeolite molecular sieve, the other is how to load the prepared zeolite molecular sieve with titanium dioxide.Firstly, the method of preparing zeolite molecular sieve is alkaline melt hydrothermal method, the pretreated fly ash is used as the main raw material, and alkali melt fly ash is added to synthesize zeolite molecular sieve.The effects of different lime-base ratio, calcination temperature and time, hydrothermal crystallization temperature and time on the synthesis of zeolites were studied.The morphology, phase and specific surface area of the product were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and specific surface area test (BET), and the yield was calculated.The test results show that when NaOH: fly ash: Na2CO3 is 1.2: 1: 0.3, calcination temperature is 550 鈩，

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