SYNERGISTIC ROLE OF SEED AND CETYLTRIMETHYLAMMONIUM BROMIDE IN THE SYNTHESIS OF HIERARCHICAL ZSM-5 ZEOLITES AND THEIR CATALYTIC PERFORMANCE

Abstract

Abstract: Both seed and CTA serve as common template agents in the synthesis of hierarchical ZSM-5 zeolites. However, their specific roles in the synthesis process remain unclear. The hierarchicalZSM-5 zeolites were successfully synthesized by using a 1.5% of seed solution and various CTA contents. The physical and chemical properties of the synthesized zeolites were characterized using X-ray powder diffraction, scanning electron microscopy, low-temperature N₂ adsorption-desorption, and Fourier-transform infrared techniques. The investigation revealed that the CTA content exerted a significant influence on the synthesis of ZSM-5 zeolites, with CTA contributing to framework filling, charge balancing, and acting as a mesoporous template, while the seed solution primarily served as a structure-directing agent. Furthermore, through the utilization of the conversion of C₈ aromatic hydrocarbons as a probe reaction, it was demonstrated that the catalyst containing hierarchical ZSM-5 zeolites synthezed by seeds and CTA exhibited enhanced conversion rates for ethylbenzene and m-xylene compared to samples synthesized exclusively with a seed solution.

Key words: zeolite, seed, template agent, C₈ aromatics conversion

References

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