Modification of ZSM-5 Catalyst Using Microwave-Assisted and Thermal Methods: Characterizations and n-Heptane Cracking Activity

In this study, mesoporous zeolite ZSM-5 samples were successfully synthesized using the microwave method, and thermal method to evaluate the efficiency of the n-heptane cracking reaction. The physicochemical properties and characteristics of the catalysts were determined by X-ray diffraction (XRD), N2 adsorption-desorption at low temperatures, and scanning electron microscopy (SEM). The effects of the n-heptane cracking reaction temperature of the modified zeolite samples between 400 and 600 °C were investigated. As a result, the mesoporous zeolites were successfully prepared, with the external area of modified zeolites increasing 12-13 times for samples with a high Si/Al ratio and increasing 1.4-3 times for materials with a low Si/Al ratio compared with the original zeolites. For zeolite ZSM-5 with a high Si/Al ratio, the microwave approach successfully modified the initial sample in 12 times less time than the hydrothermal method to obtain approximately the same mesopore surface area. The prepared zeolites with a low Si/Al ratio exhibited higher efficiency than the initial sample in the n-heptane cracking procedure, with the conversion efficiency of the former being 4.4-5.2 % higher than that of the latter.