Controllable Preparation of Zeolite P1 From Metakaolin-Based Geopolymers via a Hydrothermal Method

A more controllable method to synthesize particular zeolites from geopolymers is needed in order to effectively use these materials in industrial applications. In the present study, a well-crystallized zeolite P1 was synthesized from a metakaolin-based geopolymer (SiO2/Al2O3=3.2) using a hydrothermal method. The products obtained by hydrothermal treatment were identified using X-ray diffraction (XRD), scanning electron microscopy (SEM), and specific surface areas. The XRD patterns and SEM micrographs indicated that the structure and morphology of zeolite P1 could be controlled by the NaOH solution concentration, hydrothermal temperature, and the hydrothermal treatment time. The crystalline structure of the prepared zeolite P1 was refined using the Rietveld method and the crystal structure parameters were as follows: a = 10.01 Å, b = 10.01 Å and c = 10.03 Å. The optimal hydrothermal conditions to form zeolite P1 were 24 h at a hydrothermal temperature of 100°C and 2.0 M NaOH solution. Moreover, the synthesized zeolite P1 had a specific surface area of 36.56 m2/g.