Synthesis of Zeolite-like Material from Coal Fly Ash and Bauxite Residue

Zeolites are crystalline aluminosilicate microporous materials which have three-dimensional frameworks with arrangements of cages and uniform channels. Zeolites are used for gas adsorption due to their high surface area, uniform pore structure and high void volume, allowing gas molecules to penetrate, and become entrapped, into their microspores. In this research, I have used fly ash produced from the combustion of Ohio bituminous coal, with an industrial byproduct bauxite residue (Red Mud) to synthesize zeolite-like material. This benefits the environment by giving waste products a functional purpose, reducing waste in Ohio’s landfills, and if applied, decreasing harmful air emissions. This project’s objective was to utilize waste products—versus the conventional method’s use of pure reagents, which is energy and material intensive—to synthesize zeolites. Coal fly ash, composed of significant amounts of alumina and silica, was the feedstock for synthesis, while Red Mud was the alkalinity source to extract alumina and silica from the fly ash. The overall procedure involved leaching, polymerization, crystallization, template removal, and analysis. Analysis included characterizing the material to determine if it was zeolite-like, and whether it can be used for gas adsorption. Several batches of material have been produced during this research. As the first three were found to have low surface areas, modifications were made while synthesizing Batches 4 and 5, resulting in higher surface areas. As the surface areas were still lower than those produced using conventional methods, further testing was necessary. The outcome of this research suggested that the microwave heating time, pH level, and silica-to-alumina mass ratio are crucial parameters to improving the synthesis process. Based upon results from this study, the combination of fly ash and red mud has great potential for further research to determine whether a usable zeolite-like material can efficiently be synthesized.College of Engineering Undergraduate Research ScholarshipNo embargoAcademic Major: Civil Engineerin