Estudo do efeito de micro-ondas na síntese da zeólita MCM-22.

Abstract

Currently, one of the problems found by researchers to obtain molecular sieves, micro-and mesoporous, used as catalysts, catalyst supports and / or additives in the petrochemical industry is the long time of formation of these structures. One of the methods of optimization of the synthesis of these materials is the process of hydrothermal microwave. The heating promotes a rapid transfer of heat causes a rapid dissolution of the gel and accelerates the homogeneous nucleation in the synthesis mixture, and thus the crystallization is obtained with shorter synthesis. This work aims at finding new synthesis routes faster and economical process using the hydrothermal microwave. Zeolite MCM-22 was prepared using conventional hydrothermal methods static and microwave at different reaction times. Through the XRD patterns of the samples prepared by the conventional method combined with microwave, confirmed the acquisition of zeolite MCM-22 with 6 days of synthesis. Through the results of N2 adsorption, it is found that zeolite MCM-22 6 days per a conventional method combined with microwave for 1.5 to 2.0 hours, showed textural characteristics typical isotherm with type I and H4 hysteresis. FTIR spectra showed that the driver has been removed confirming the formation of zeolite MCM-22. The SEM carried out for 10 days the sample by the conventional method, considered as our standard, showed spherical morphology depression in the central region.