Avaliação da influência dos parâmetros de síntese na preparação de membranas zeolíticas Y/a-alumina.

Abstract

The zeolite membranes Y type are materials were one or more tickness of type Y zeolite are deposited about a porous support, one of the most important potential applications dehydration with solvents in processes of pervaporation, separation of liquids, organic catalysis and the separation of gases. The present work aims to increase the scientific knowledge of the phenomena involved in the formation of Y/a - alumina zeolite membranes using the method of secondary growth - rubbing and evaluating the influence of synthesis parameters (composition, agitation temperature, silica source, time of hydrothermal treatment and synthesis methodology) in the preparation of membranes. Under the conditions of synthesis and evaluated with the silica source used was found that the method offers the best crystallinities B in Y zeolites obtained. The time of hydrothermal synthesis was sensitive to silica source employed which was determined to silica Aerosil 200 and Aerosil 380 silica were required 24 hour hydrothermal treatment by the methods A and B respectively and to sodium silicate were required only 7 hours. In the synthesis of zeolite membranes Y silicate as the silica source and time of hydrothermal treatment of 24 hours was found that using ratio SiO2/AI2O3=10, 12 and 14 no formation of other phases. The crystallinity of zeolite Y with Si02/AI203 ratio increased . For membranes in which zeolite was used Aerosil 380 silica there was an increase in the crystallinity of Y with increasing Si02/Al203 ratio but this sequence of experiments the crystallinity of the zeolite layer is too low.