关键词: ZSM-5分子筛, 碱脱硅, 多级孔, 结构表征, 扩散性能

Abstract: The pore structure of ZSM-5 zeolites was modulated with sodium hydroxide solution. The diffusivity of cyclohexane in ZSM-5 zeolites and the correlation between diffusivity and NaOH desilication time were studied by zero length column (ZLC) method. The pore volume and pore size distribution of micropores and mesopores of ZSM-5 zeolites were characterized by Ar adsorption-desorption method, and transmission electron microscopy (TEM) was used to study the structure and connectivity of mesopores in ZSM-5 zeolite with different NaOH desilication time. These experimental results show that the volume and connectivity of mesopores are increasing along with alkali treatment time, which increases the diffusivity of cyclohexane in ZSM-5 zeolites. With the increasing of NaOH desilication time, the proportion of mesoporous channels larger than 10 nm gradually increases, and these larger mesopores further improve the diffusivity of zeolites.

Key words: ZSM-5 zeolite, NaOH desilication, hierarchiecal pore, structure characterization, diffusion properties