TRANSFORMACIÓN HIDROTERMAL DE PERLITA EXPANDIDA EN ZEOLITA ZSM-5. ESTUDIO DE LAS CARACTERÍSTICAS ACIDAS

PABLO CORREGIDOR; DELICIA ACOSTA; HUGO DESTÉFANIS

Valparaiso

Congreso; CONAMET/SAM 2012-12º Congreso Binacional de Materiales y Metalurgia; 2012

Universidad Técnica Federico Santa Maria-Valparaiso Chile

ZSM-5 zeolite has been prepared by hydrothermal synthesis from Expanded Perlite as the only Al source. The influence of parameters as pH, SiO2/Al2O3 and H2O/SiO2 was studied in the preparation. ZSM-5 zeolite has been identified by XRD, showing that different crystallographic phases, as Analcime, can be obtained by changing conditions in the synthesis procedure. The generation of MFI framework is evidenced by the presence of an absorption band at 545 cm-1 in the Infra-Red spectrum, this band is absent for Perlite and Analcime. From 29Si NMR spectroscopy we calculated a Si/Al molar ratio of 12 in the obtained material, and 27Al NMR was employed to confirm the incorporation of Al in the framework. The zeolite is present as well-defined coffin-shaped crystals with a BET surface area of 380 m2.g-1. TPD of pyridine and lutidine reveal a high concentration of acid sites maintaining a 70 % from the total interacting with pyridine at 350 °C. Quantification with lutidine shows the concentration of sterically hindered acid sites and probes that most of them are predominantly in the microporous surface of the material.