Preparation and Characterization of Niobium LTA modified Zeolite catalyst.

CORREGIDOR, PABLO; ACOSTA, DELICIA; DESTÉFANIS, HUGO

Roma

Congreso; NANO; 2010

Microporous materials with regular pore architecture comprise wonderfully complex structures and compositions. Their fascinating properties, such as catalysts and their roles as hosts in nanocomposite materials, are essentially determined by their unique structural characters. Zeolites [1] constitute the most important family in microporous materials; a representative example of a widely used zeolite is LTA. Zeolites possess acid sites on the surface which can catalyse many reactions such as transesterification [2], this acidity might be increased by introducing transition metal in different oxidation states and coordinations, and so, incorporation of Niobium into microporous molecular sieves brings up new properties for these materials as solid acid catalyst. In the present contribution, LTA zeolite was synthesized using an amorphous glass with expansive capacity from the NOA region of Argentina -Perlite- as a silicon source. Structural changes, in the crystalline structure of zeolite were made by adding niobium using ?reactive sublimation? as a method of preparation. This was realized on a previously conditioned chamber at 523K. Nb-LTA and starting materials were characterized by FT-IR, DSC, SEM and DRX. Also, surface area, pore volume and pore distribution were obtained by the BET method of nitrogen adsorption isotherms at 77 K. Nb-LTA showed a preservation of the zeolitic structure after reactive sublimation as confirmed by XRD. The presence of niobium covalently bonded to the zeolite structure was confirmed by FT-IR, according to the existence of Si-O-Nb shoulder at 850-910 cm-1. The Niobium content was quantified by XRF and EDS. This methodology allows for Nb-LTA modified zeolite, designed as a heterogeneous acid catalyst that can be used in transesterification reactions.