Optimization of Pretreatment and Hydrothermal Process of Na-X Zeolite from Kaolin and Metakaolin

Synthesis of Na-X zeolite was conducted from kaolin and metakaolin. Synthesis varied in its pretreatment method and hydrothermal conditions. The pretreatment methods used were: conventional alkaline, alkaline fusion and conventional fluoride. Hydrothermal conditions for the experiments were gradual temperature 40°C (6h), 60°C (6h), 80°C (12h), and constant temperature 80°C for 24 h, 100°C for 24 and 100°C for 48 h. Synthesized products were characterized by X-Ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), and N₂ Isotherm Adsorption/Desorption method. The result showed that pre-treatment by conventional fluoride could not produce Na-X zeolite, synthesis by conventional alkaline and alkaline fusion with hydrothermal at 100°C (48h), 100°C (24 h), and gradual temperature produce Na-X zeolite with Na-P1 or Na-A zeolite as impurities, while synthesis from metakaolin by conventional alkaline with hydrothermal at 80°C for 24 hours produced pure Na-X zeolite. Na-X zeolite and Na-P1 zeolite with hierarchical pores were synthesized through alkali fusion with hydrothermal at 100°C for 24 hours.