Synthesis of pure Na–X and Na–A zeolite from bagasse fly ash

Bagasse fly ash (BFA), a solid waste from sugar cane industries, is still underutilized leaving disposal problems. In fact, high silica content inside this material opens a possibility to become a potential zeolites precursor. In this study, fine particles of BFA has been reused to prepare zeolite Na–X and Na–A with high purity. After segregated by mechanical sieving, the small particle fraction of BFA has been subjected to alkali fusion treatment followed by dissolution and then residue separation to produce clear silicate supernatant as the silica source for preparing the low-silica zeolites. High purity of Na–X and Na–A zeolites were prepared using hydrothermal treatment by optimizing the process condition, i.e., curing time, hydrothermal temperature and Si/Al molar ratio in the reaction mixture. Furthermore, the effect of several anions on the rate of zeolite X crystallization was also investigated.