Banca de QUALIFICAÇÃO: TOMAZ RODRIGUES DE ARAÚJO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : TOMAZ RODRIGUES DE ARAÚJO
DATE: 13/03/2023
TIME: 15:00
LOCAL: Auditório do CCET - NUPPRAR
TITLE:

POTENTIALITY OF JATOBÁ WASTE (Hymenaea Courbaril L.) IN THE SYNTHESIS OF ZnFe₂O₄-Fe₂O₃-ZnO VIA MICROWAVE-ASSISTED SELF-COMBUSTION AND GREEN SYNTHESIS

KEY WORDS:

Jatobá wood waste; Green synthesis; Microwave assisted self-combustion; heterostructures and ZnFe2O4-Fe2O3-ZnO.

PAGES: 100
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The purpose of this work was the reuse of jatobá wood waste to synthesize ZnFe 2 O 4 -Fe 2 O 3 -ZnO heterostructures by two synthesis routes: microwave-assisted self-combustion and the green synthesis route. The residues (liquid and solid) used were extracted by a hot process (temperatures: 50, 60, 80 ºC), and the liquid part was used in microwave-assisted combustion replacing (in 50 and 100%) the water used in the synthesis and the solid part in the green synthesis as a structure and pore driver. X-ray diffraction (DRX), scanning electron microscopy (SEM-EDS and SEM-FEG), thermogravimetric analysis; immediate analysis; calorific value and thermal capacity; to helium gas density; infrared (FTIR), Raman and ultraviolet and visible (UV-vis) spectrophotometry, diffuse reflectance (DRS) and light scattering particle size (DLS) were the techniques used in the characterizations. In addition, yield analyzes of the extraction process and syntheses were carried out. From the results: The immediate analysis shows moisture lower than 20%, high percentages of volatiles, low levels of ash and fixed carbon. The raw and post-extraction residues have specific heat from 950.13 to 9,091.98 cal/gºC and thermal capacity (2,433.10 – 2,504.03 cal/ºC). There was formation of ZnFe 2 O 4 -Fe 2 O 3 -ZnO by the green synthesis route and ZnFe 2 O 4 -Fe 2 O 3 by microwave-assisted self-combustion, and also the monolithic phase (ZnFe 2 O 4 ). The crystallite size was from 14.5 to 126.3 nm, crystallinity from 35.79 to 69.62 nm and band gap from 1.79 to 2.46 eV. The microscopies show diversified morphologies with signs of cavities and channels with orientations consistent with those of the fibers present in the residues. DLS shows stable particles between 148.50 and 1,823.17 nm and positive surface charge. The results showed that the use of jatobá wood residue in the synthesis of ternary heterojunctions produced stable structures with consistent properties, which implies adding value to the jatobá residue with its technological application in the synthesis of ternary heterojunctions, whose yield in mass was close to 2% and in volume of solubles it was above 70%.

COMMITTEE MEMBERS:
Presidente - 6347420 - MARCUS ANTONIO DE FREITAS MELO
Externa ao Programa - 1979301 - RENATA MARTINS BRAGA - UFRNExterno ao Programa - 3304576 - RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS - UFRNExterno à Instituição - GILVAN PEREIRA DE FIGUEREDO - IFMA
Externo à Instituição - ÂNGELO ANDERSON SILVA DE OLIVEIRA