Thermal stability studies of zeolites A and X synthesized from South African coal fly ash
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The thermal stability of zeolites A and X synthesized from coal fly ash was studied by evaluation of TGA–DTA curves obtained on increasing the temperature and by in-situ temperature-programmed XRD analysis. It was found that zeolites A and X were both stable up to approximately 800 °C and retained their characteristic diffraction peaks up to 440 °C, meaning the crystal structure was still stable. Of particular interest was that zeolite X, which has a unique hierarchical morphology, was thermally stable and was, hence, suitable for applications requiring elevated temperatures, for example catalysis and pollution control.
KeywordsZeolites Fly ash Thermal stability In-situ XRD
The authors of this paper would like to acknowledge and thank DAAD for supporting Nicholas Musyoka during his research visit to the University of Erlangen-Nürnberg, Germany. Andreas Kuhnt and Wilhelm Schwieger appreciatively acknowledge funding by the German Research Council (DFG), which supports the Cluster Excellence “Engineering of Advanced Materials” at the University of Erlangen-Nürnberg. Assistance offered by Alexandra Inayat and Albert Machoke during the SEM analysis is also appreciated.
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