HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF ZEOLITE TYPE A FROM FLY ASH

Abstract

In this study, Zeolite Type A was successfully synthesized from coal fly ash using an alkaline hydrothermal method. The pretreatment of fly ash with acid followed by dissolution in NaOH and hydrothermal crystallization at 100 °C yielded phase-pure Zeolite A with high crystallinity. X-ray diffraction confirmed the formation of the cubic LTA framework structure, while FTIR spectroscopy revealed characteristic framework vibrations of Si–O and Al–O tetrahedra along with structural water bands. SEM micrographs showed well-defined cubic crystals with intergrowth typical of Zeolite A, and EDS analysis confirmed the presence of Si, Al, O, and Na as the major elements with trace impurities such as Ca and Fe from fly ash. The results demonstrate that fly ash, an abundant industrial by-product, can be effectively converted into a high-value zeolite material, thus providing both waste utilization and sustainable synthesis of functional porous materials.