Banca de DEFESA: SERGIO ANTONIO DE PAIVA ROCHA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : SERGIO ANTONIO DE PAIVA ROCHA
DATE: 19/01/2026
TIME: 15:00
LOCAL: Auditório do NUPPRAR/LABPROBIO
TITLE:

PYROLYSIS OF Desmodesmus sp MICROALGAE PRETREATED AND CATALYZED BY CO/γ -AL2O3 AND MO/γ –AL2O3 FOR THE PRODUCTION OF BIOPRODUCTS

KEY WORDS:

Microalgae, Acetylation, Mo/γ-Al2O3, Co/γ-Al2O3, Pyrolysis, Renewable hydrocarbons, Energy Transition.

PAGES: 180
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The growing demand for sustainable energy alternatives has driven the development of thermochemical pathways for biomass conversion. In this study, we investigated the pyrolysis of the microalgae Desmodesmus sp. pretreated with acetylation in the presence of Mo/γ-Al2O3 and Co/γ-Al2O3 catalysts, evaluating the influence of the active metal and temperature on the distribution and selectivity of the products formed. The microalgae were characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA/DTG). Acetylation, performed three times, proved to be effective in producing biomass suitable for pyrolysis, with low moisture (6.60%) and ash (7.72%) contents and an increase in lipid content (49.56%). Molybdenum and cobalt metals were impregnated into γ-Al2O3 by the wet impregnation technique at a percentage of 10% and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), acidity by desorption and thermodesorption of n-butylamine, and scanning electron microscopy coupled to an energy-dispersive spectrometer (SEM/EDS). The impregnation of the metals was effective, without altering the structure of γ-Al2O3, with a percentage of metals close to the target value of 12.45% for Mo and 11.21% for Co. The insertion of Mo metal allowed acidity control favorable to pyrolysis reactions, with a total acidity of 0.73 mmol/g. Pyrolysis tests, conducted at 300 °C and 500 °C, with and without catalysts, and analyzed by Py-GC/MS, demonstrated that the temperature change alone did not affect the products obtained. However, the presence of catalysts significantly altered the composition of the products. The best response occurred in the Mo/γ-Al₂O₃ catalyst combination at 500 °C with high selectivity for propanoic acid, 2-hydroxy-2-methyl, and methyl ester, accounting for a concentration of 81.61%. The denitrogenating action was verified, completely reducing the concentration, compared to 30.79% for thermal pyrolysis. Regardless of the temperature and catalyst applied, the predominant hydrocarbon fraction was kerosene, with the MAcMo500 test standing out with 99.28% of this fraction, followed by the MAcCo300 test (76.77%). The results demonstrate the potential application of the microalgae Desmodesmus sp. in biorefineries aimed at the production of advanced fuels and value-added chemical inputs.

 

 

COMMITTEE MEMBERS:
Presidente - 2140818 - AMANDA DUARTE GONDIM
Externa à Instituição - ARUZZA MABEL DE MORAIS ARAUJO - UFRN
Externa à Instituição - EDJANE FABIULA BURITI DA SILVA - UFRN
Externo à Instituição - JOAO PAULO DA COSTA EVANGELISTA - UFRN