Preparation and characterization of hierarchical USY by post-treatment

Abstract

Two modifying agents, citric acid and EDTA-2Na, were used to modify USY zeolite to obtain the hierarchical USY with high crystallinity. XRD, N2 isothermal sorption, 27Al and 29Si NMR, and TEM were adopted to characterize the dealumination process in the post-treatment of USY. The results showed that all modified USY have increased surface areas and pore vol. due to the removal of non-framework Al species. Besides, framework dealumination occurred in the modification process. USY-EC, which was modified by the combined effects of citric acid and EDTA-2Na, has the highest SiO2/Al2O3 ratio of 19.40 and relatively high crystallinity. [on SciFinder(R)]