Study of the zeolite of Zeolites ZSM-35 (FER) and ZEM-5 (MFI) and application of these materials as catalysts for biomass pyrolysis.
ZSM-5, MFI, ferrierite, FER, catalysis, biomass pyrolysis
Zeolites are porous materials with a crystal structure belonging to the class of molecular sieves. The syntheses of zeolitic materials can be modified, varying the parameters according to the needs of the final material. The purpose of these variations, usually, are to obtain a more crystalline structure and a possible change in morphology to improve the catalysis reactions. This study presents the characterizations of the different syntheses carried out of the ZSM-35 zeolite (FER) and the characteristics of the commercial ZSM-5 zeolite (MFI) with zirconia impregnation. The ZSM-35 syntheses were initially studied using the recipe presented at the IZA (International Zeolite Association) and later varying some parameters, such as the sources of silicon and aluminum, the variation of the Si/Al ratio and the use of the cationic surfactant, bromide hexadecyltrimethylammonium (CTAB). In addition to possible changes in the final material, the use of alternative sources of silicon and aluminum, which are sources easily found in nature, brings great cost-benefit to the process. For the characterization of these materials, the techniques of X-ray diffraction (XRD), X-ray fluorescence (FRX), scanning electron microscopy (SEM), thermogravimetric analysis (TG), and textural analysis by N2 adsorption were used ( BET method). It was observed that in the syntheses studied following the IZA recipe and with the different sources of silicon and aluminum, a good crystallinity of the FER structure was obtained in an optimized time in relation to the literature, as well as in the syntheses with the use of surfactant. However, with the addition in the syntheses using the surfactant, with Si/Al ratio 30.4, we obtained another structure, ZSM-5 (MFI), instead of ZSM-35 (FER). After the step of studying the syntheses, it was followed by their applications as catalysts for biomass pyrolysis. Three biomasses were tested for bio-oil production by rapid pyrolysis. In the characterization of the products obtained in the reactions, the techniques of gas chromatography, elemental analysis CHNS-O, thermogravimetric analysis and moisture analysis (Karl Fisher) were used. It was observed that the use of the catalyst in the reaction led to a drastic reduction in the bio-oil, however it led to a greater production of CO and CO2, which are molecules that reduce the oxygen content in the bio-oil.