The synthesis of SAPO-34 catalyst using various sources of silicon and aluminum

Silicoaluminophosphate, SAPO-34, is known as promising molecular sieve, which is widely used in catalysis, separation processes, and are being developed for new applications, especially in the methanol-to-olefin (MTO) process.To investigate the effects of sources on the SAPO-34 structures, SAPO-34 catalysts were synthesized using different precursors of aluminum and silicon with nominal composition as 1Al2O3: 1P2O5: 0.4SiO2: 1.5 Morpholine: 0.5 TEAOH: 70 H2O. The different SAPO-34 samples were characterized by XRD and SEM and FTIR techniques. Depending on the various sources of Si and Al used for the synthesis, SAPO-34 materials with different crystal size, degrees of crystallinity and acid sites have been prepared. According to the XRD and SEM, highest crystallinity and smallest crystal size was formed when silica gel and aluminium isopropoxide were used as Si and Al precursors. The FTIR results showed that there was no considerable increase in the concentration of strong acidic hydroxyl groups with changing the precursors

Keywords:

SAPO-34 , Synthesis , Crystallinity , precursor