Banca de DEFESA: RENATA CIBELY FREIRE DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RENATA CIBELY FREIRE DE LIMA
DATE: 07/04/2025
TIME: 14:00
LOCAL: Modo Remoto
TITLE:

SYNTHESIS OF MFI-TYPE ZEOLITES FROM ALTERNATIVE SOURCES OF Si AND AL: A SUSTAINABLE APPROACH TO THE CONVERSION OF BIOMASS INTO BIOFUELS AND RENEWABLE CHEMICALS

KEY WORDS:

Corn cob, catalytic pyrolysis, rice husk, deoxygenation, HZSM-5.

PAGES: 99
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

Fast pyrolysis has emerged as a promising technology for converting lignocellulosic biomass into bio-oil, a potential precursor to fuels. However, the conventional pyrolysis of such biomass produces bio-oil with a high concentration of oxygenated and nitrogenous compounds, which compromises its properties for energy applications. The use of catalysts, such as zeolites, improves the chemical composition of bio-oil, making it more suitable for conversion into biofuels and higher-value-added chemicals. This study synthesized MFI-type zeolites using bentonite, rice husk ash (RHA), and clinoptilolite as alternative Si and Al sources for application in catalytic analytical pyrolysis of lignocellulosic biomass. The goal was to improve the quality of the generated bio-oil by reducing the content of oxygenated compounds, costs, and environmental impacts. The synthesis was carried out using the hydrothermal method, varying the gel crystallization times (24 h, 48 h, 72 h, and 7 days). As a reference, a conventional ZSM-5 was prepared using Aerosil silica and aluminum sulfate. The biomass used, corn cob residue (CCR), was characterized to evaluate its energy potential through proximate analysis for determining moisture, ash, volatile matter, and fixed carbon content, as well as elemental analysis (CHN/O), thermogravimetric analysis (TG/DTG), and calorific value determination. The precursors and synthesized catalysts were analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and specific surface area analysis using the BET method. Analytical pyrolysis was performed in a micro-pyrolyzer connected to a gas chromatograph (Py-GC/MS) at 500 °C, with vapors analyzed by chromatography and identified by mass spectrometry (GC-MS) or directed to a catalytic bed (ex-situ catalytic pyrolysis) for further analysis. Catalytic pyrolysis reduced oxygenated and nitrogenous compounds compared to conventional pyrolysis, decreasing phenols and ketones while increasing aromatic hydrocarbons. The zeolite synthesized with alternative precursors, such as bentonite and RHA, exhibited an MFI structure similar to conventional ZSM-5. In catalytic pyrolysis tests, both materials performed similarly, with the process being more sustainable for the zeolite obtained from bentonite and RHA. Regarding methodology, the use of catalysts proved to be reproducible, achieving the objectives of this study.

COMMITTEE MEMBERS:
Interno - ***.656.434-** - CARLOS EDUARDO DE ARAÚJO PADILHA - UFRN
Interna - 1979301 - RENATA MARTINS BRAGA
Externa ao Programa - 1308577 - SIBELE BERENICE CASTELLA PERGHER - UFRNExterno à Instituição - Fabio Souza Toniolo
Externa à Instituição - MARIELE IARA SOARES DE MELLO - UFRN