Effect of secondary template polarity to the properties of mesoporous ZSM-5 zeolites

Synthesis and characterization of mesoporous ZSM-5 using two kinds of secondary templates with different polarity, polydiallyldimethylammonium chloride (PDDA-Cl) or cetyltrimethylammonium bromide (CTABr) were studied. The weight lost after calcination at 550 °C for 5 hours were 30.93 wt% and 25.87 wt% for PDDA-Cl-templated ZSM-5 (ZSM-5_pc) and CTABr-templated ZSM-5 (ZSM-5_cs), respectively. Both as-synthesized mesoporous ZSM-5 zeolites then were characterized by XRD, FTIR, SEM, and EDX. Based on wide angle XRD analysis that both mesoporous ZSM-5 showed similar diffraction patterns and the typical peaks of ZSM-5 in which 2θ = 7°-9° (doublet peaks) and 22°-25° (triplet peaks) appeared. For the analysis of functional group, FTIR analysis showed that both mesoporous ZSM-5 gave strong band at 550 cm⁻¹, which is attributed to asymmetric stretching vibration of the double 5-rings from MFI zeolites. Meanwhile, the result of EDX calculation showed mesoporous ZSM-5_pc had Si/Al ratio of and ZSM-5_cs had Si/Al ratio of 12.62. Furthermore, the SEM images exhibited mesoporous ZSM-5_pc had morphology of hexagonal (coffin-like) while ZSM-5_cs had ellipse form.