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Abstract
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In this research, simultaneous efect of Si source and CTAB application as surfactant was investigated in SAPO-34 preparation used for MTO process. Prepared samples were evaluated by FESEM, XRD, FTIR, BET and EDX analysis. TEOS application as Si source results in small crystallites of SAPO-34 due to its better solubility and smaller size. Consequently, in this case, CTAB cations could perform their hydrophobic capping efect more efciently, because it is easier to create a hydrophobic cap around small crystallites compared to large ones. In case of fumed silica application, it seems that CTAB molecules cannot function as hydrophobic cap due to the larger crystallite size. The mentioned explanation was supported by the presented FESEM analysis. SAPO-34 with fumed silica as Si source has large crystallites which is leading to longer intracrystalline difusion length enough for the reaction species and fnally turning out to be coke deposition.
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