Novel Procedure for Synthesis of SAPO-34 Nano Crystals Using Aluminum Chloride as Aluminum Source and Investigation of the Influence of Different Parameters on their Synthesis

Silicoaluminophosphate (SAPO-34) molecular sieve was successfully synthesized via hydrothermal procedure using aluminum chloride as the source of aluminum and diethylamine (DEA) as a template. The influence of template amount (effect on pH of precursor gel) and crystallization temperature and time on the synthesis of chabazite structure related to SAPO-34 were investigated. The samples were characterized by XRD, FT-IR, FESEM and TEM techniques. According to the XRD analysis, it was found that by decreasing the pH and crystallization temperature the probability of chabazite phase production is reduced. The analysis of the XRD reflections by Scherrer´s equation provides the particle size of 36-44 nm for SAPO-34 catalysts. Also, crystallinity, crystallite size, and purity of samples were compared together. We also found that the crystallite size increases with increasing of pH and in crystallization time of 26 h. Also, it was found that the synthesis conditions greatly affected the morphology of SAPO-34 catalysts. The FESEM analysis confirmed SAPO-34 samples synthesized in the presence of a larger amount of template were in spherical morphology.