Characterisation of NAA zeolite made from Malaysian kaolin

Abstract

In this study, as an alternative to the pure chemical used to prepare zeolite NaA, the clay mineral kaolinite was used as the source material for NaA-zeolite preparation. Kaolin as an alternative low cost material and as a potential precursor to zeolite A synthesis via metakaolinisation of kaolin at 900 °C to a reactive amorphous material called metakaolin and hydrothermal treatment of metakaolin with an aqueous alkali. Before this reaction takes place however, raw kaolin undergoes a pretreatment process to increase its purity through the removal of impurities. This research intends to prepare zeolite A from Malaysian kaolin. A series of composition and structural characterisations of both the starting material (kaolin) and the final product (zeolite A) were carried out using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) to confirm the formation of NaA-zeolite. From the characterisation studies, it was found that high-purity NaA-zeolite can be produced from local kaolin. These findings enable us to answer the fundamental question regarding the structural characteristics of NaA-zeolites synthesised from Malaysian kaolin.