Date of Degree
MS (Master of Science)
Sarah C. Larsen
Nanocrystalline ZSM-5 zeolite, which is a well-known catalyst used in a variety of applications in industry, environment, and medicine, can be synthesized using different methods. However, a big challenge in synthesizing nanocrsytalline ZSM-5 is the use of an organic template such as TPAOH, which is very expensive. The template is required to facilitate the growth of the nanocrsytalline ZSM-5 during the synthesis. However, to use the nanocrsytalline ZSM-5, the template has to be removed by a calcination process to open the pores and reveal the active surface of the nanocrystalline ZSM-5. The calcination process requires a high temperature for a long time to remove the organic template. Consequently, synthesizing nanocrystalline ZSM-5 by using a templated method is considered to be time, energy, and materials inefficient. In addition, the production of CO2 from the calcination process is a negative impact on the environment. Therefore, finding another method to synthesize nanocrystalline ZSM-5 without using an organic template would be beneficial. Here, nanocrystalline ZSM-5 was synthesized successfully in high yield and quality by using a seed-assisted method and without using the organic template. In addition, the effect of synthesis temperature, synthesis time, basic environment, amount of seeds, size of seeds, aging time, and use of calcined and uncalcined seeds are investigated in this study. The synthesized nanocrystalline ZSM-5 materials were characterized by using X-ray diffraction (XRD), gas adsorption isotherm (BET/BJH), and transmission electron microscopy (TEM).
Nanocrystalline ZSM-5 zeolite, which is a type of porous aluminosilicate material can be used in a variety of applications in industry, environment, and medicine. Nanocrystalline ZSM-5 can be prepared using different synthetic approaches. Almost all of these methods require a template, such that the nanocrystalline ZSM-5 materials are formed around the template and then the template is removed to introduce the porosity. The removal process can be done by heating the materials for a long time to decompose the template, but during this process carbon dioxide gas, which is considered harmful to the environment, is also formed. Consequently, using the template to form these nanocrystalline materials is considered time, energy, and money inefficient. Therefore, finding another way to synthesize these nanocrystalline materials without using the template would be beneficial. Here, nanocrystalline ZSM-5 materials were successfully formed by a new method without using the template. In this method, the yield and the quality of the materials are very high. In addition, the conditions that are used such as the time, the temperature, and the chemical materials used are changed in a way that helps to study the effect of these conditions on the formation of the desired materials. The obtained materials were characterized by using different instruments that help to identify the type and the properties of the materials.
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