Banca de QUALIFICAÇÃO: RAFAEL CHAVES LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAFAEL CHAVES LIMA
DATA : 29/09/2017
HORA: 14:00
LOCAL: Auditório do CCET
TÍTULO:

MORDENITE: STUDY ABOUT ITS FORMATION AND CRYSTAL SIZE

PALAVRAS-CHAVES:

MORDENITE, ZEOLITE, FORMATION, CRYSTAL SIZE

PÁGINAS: 190
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Físico Química Inorgânica
RESUMO:

Zeolites are materials that can be defined as crystalline microporous solids whose composition allows their generalization as a class of complex hydrated silicates. This type of crystal has been studied in excess, especially for catalytic applications. One of these zeolites, the mordenite, is of great industrial interest because of its applicability in the field of catalysis, being a zeolite with good catalytic performance, besides being suggested for other utilities. Although zeolites have good catalytic performance, the restricted size and extent of their pores imply mass transfer problems and hinders their application in cases of molecules too large to enter or difficult to diffuse through the pores. Given the motto, many studies of synthesis of porous materials are dedicated to the problem of accessibility and many alternatives have been suggested and one of the suggested alternatives is the control of the size of the crystals. Since the intraporous diffusion presupposes a path, which the species in reaction have to travel until they become free to the reaction medium, the control of the length of the zeolitic channels is a preponderant factor in the design of zeolites for specific uses. In this context, controlling crystal size has been one of the propositions to govern the diffusional path and improve pore accessibility and is one of the new focuses of "zeolitic engineering". In the first instance, nanometric crystals can be synthesized under hydrothermal conditions similar to conventional zeolites. However, investigations on synthesis indicate that supplementary care should be imputed to the preparation of the precursor gel and to the crystallization conditions in a way that favors nucleation. Thus, in the present work it is proposed to evaluate how the synthesis conditions, reagents and variables implied to the zeolitization system influence the size of the mordenite zeolite crystals. The syntheses were based on a standard procedure based on the IZA standard procedure, from which parameters of the synthesis condition, time, temperature, water content and degree of purity,  ions content, gel aging time and Variation of the silicon source by observing its impact on crystal growth as well as its morphology. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the vibrational infrared region with Fourrier Transform (FT-IR) and thermogravimetric (TG) analysis. As a result, it was possible to decrease the size of the mordenite crystals by controlling the temperature, time, water content  ions content and silicon source type.

MEMBROS DA BANCA:
Presidente - 1308577 - SIBELE BERENICE CASTELLA PERGHER
Externo ao Programa - 2302898 - ELEDIR VITOR SOBRINHO
Externo à Instituição - VINÍCIUS PATRÍCIO DA SILVA CALDEIRA - UERN