Influence of desilication conditions on the shynthesis of herarchical zeolite Y

Hierarchical zeolites were synthesized by two methodologies, following desilication procedures of commercial zeolites. Starting from USY zeolite (Zeolyst CBV720,Si/Al=15), the effect of the amount of CTAB in the desilication media and the hydrothermal treatment time on the synthesized materials were analyzed.The results showed that the surfactant amount has a higher influence on relative crystallinity (%RC) and textural properties of the materials than synthesis time. All the samples showed a lower BET surface area compared with the starting zeolite, although mesopore surface area increased from 210.33 to 467.30 m2/g in the case of Z720-75sample. In the case of USY zeolite withSi/Al=2.6 (ZeolystCBV500),a previous dealumination with H4EDTA and anacid washingwith Na2H2EDTAsteps were included.It was found that the micropore and the mesopore surface areasincreased 13.96% and 11.23%, respectively, compared with the parent zeolite; furthermore, the %RC was 99% after treatmentprocedures.