Conversion of coal fly ash into nanozeolite Na-X by applying ultrasound assisted hydrothermal and fusion-hydrothermal alkaline activation

This research is emphasized on the synthesis of micro-mesoporous nanozeolite Na-X from coal fly ash wastes (CFA) by ultrasound assisted hydrothermal and double stage fusion-hydrothermal alkaline activation. The products from CFA zeolitization were studied with respect to their morphology by scanning electron microscopy (SEM), chemical and phase composition by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD), respectively. Their thermal properties were investigated by thermogravimetry (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC) and surface characteristics by nitrogen adsorption. The effects of the ultrasound agitation and additives on the zeolitization process were studied. Sonicated CFA Na-X zeolites possess nanocrystalline morphology and mixed micro-mesoporous structures with higher external specific surface area as compared to microcrystalline zeolite Na-X prepared by magnetic stirring. CFA nanozeolites of Na-X type are expected to behave excellent adsorption potential and catalytic activity due to the enlarged surface and fine morphology with uniformly distributed particles of iron oxides transferred from the raw material.