Hierarchical ZSM-5 Zeolite: Preparation by Sequential Desilication-dealumination and Catalytic Performance in Methanol to Gasoline Reaction

Hierarchical ZSM-5 zeolites were prepared by desilication and sequential desilication-dealumination using commercial ZSM-5 zeolite as raw material. The samples were characterized with XRD, FT-IR, SEM, TEM, and N2 adsorption-desorption isotherms. The catalytic performance was investigated in methanol to gasoline（MTG） reaction. The results indicated that the hierarchical ZSM-5 zeolite catalysts with abundant intracrystalline meso-and macropores could be prepared by desilication or sequential desilication-dealumination treatment. Compared with commercial ZSM-5 zeolite, the hierarchical ZSM-5 zeolites had higher mesopore surface area, larger mesopore volume and higher accessibility index, but with less acid amount and lower acid strength. The results of catalytic performance evaluation showed that the gasoline yield and lifetime of hierarchical ZSM-5 zeolite catalysts were significantly enhanced after modification. Simultaneously, the yield of aromatic hydrocarbon was reduced. Compared with the sample prepared by the desilication treatment, physicochemical properties and catalytic performance of the hierarchical ZSM-5 zeolite prepared by sequential desilication-dealumination treatment were improved.