Synthesis of ZSM-22 in Static and Dynamic System Using Seeds

Abstract

ZSM-22 was synthesized using various sources of silica, organic template 1,6-diaminohexane, under hydrothermal conditions, with and without agitation during crystallization. Subsequently, the crystallized material was used as seeds to accelerate the crystallization process. Characterization of the ZSM-22 samples was performed by XRD, ATG/DTG and FT-IR. It was found that it is possible to synthesize ZSM-22 employing colloidal silica and pyrolytic silica as silicon sources only if the system is stirred during crystallization. The crystallization time for these systems was 13 hours, longer times of crystallization do not significantly increase the crystallinity of the sample. The addition of seeds significantly accelerates the crystallization of ZSM-22, reducing the crystallization time to only 7 hours, with stirring and with systems employing colloidal silica.