Dynamic light scattering investigation of CTAB/swelling agent/water mixture for designing of hierarchical ZSM-5 zeolites with favorable mesoporosity

摘要

In this project, a series of hierarchical ZSM-5 zeolites with various mesopore sizes were synthesized by using trimethylbenzene (TMB), decane and dodecanethiol as micellar expanders. Firstly, an environment was designed to investigate the effect of different concentrations of micellar expanders on the formation of cetyltrimethylammonium bromide (CTAB) micelles. Then, the results were used to synthesize hierarchical ZSM-5 zeolites. The dynamic light scattering technique was employed to characterize the micelle formation mechanism besides determining the size of the micelles. Also, SEM, BET and XRD analyses were used to characterize the hierarchical ZSM-5 zeolites. The results showed that each micellar expander has a different interaction with CTAB molecules which helped us to prepare a desirable hierarchical ZSM-5 zeolite with different pore sizes and structures. By using this strategy, we succeeded to synthesize three different hierarchical microporous/mesoporous zeolites with enlarged pores at around 5, 7 and 10 nm. GRAPHICS .