Microstructural Characterization of Silicalite Crystals Obtained by Sol-Gel Hydrothermal Method

摘要

Zeolite powders (ZSM-5) and films on different porous supports of Al_2O_3, Al_2O_3/TiO_2 and Al_2O_3/Cr_2O_3 were prepared using the hydrothermal sol-gel synthesis. The morphology of the zeolite powders prepared from sodium silicate as raw material used as SiO_2 source was characterized to determine the crystallization conditions. To clarify the growth process of the silicalite crystals, the microstructural study was applied to the crystals that formed in the same time as the membranes. Different treatment temperatures and the presence of the ceramic support on the crystallization of zeolites were studied. Both the zeolite powders and the membranes were analyzed by means of XRD, IR and SEM. The XRD data showed powders after the hydrothermal treatment having the chracteristic structure of the silicalite; the SEM results showed the effect of the ceramic support on the particle shape and size.