Banca de DEFESA: NADSON HUMBERTO COSTA FERRER

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NADSON HUMBERTO COSTA FERRER
DATE: 29/07/2022
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

CARBON POINTS OBTAINED FROM SUGAR CANE BAGASSE AND THEIR APPLICATION AS FLUORESCENT MARKERS OF ETHANOL FUEL

KEY WORDS:

carbon dots; marker; hydrous ethanol fuel.

PAGES: 99
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

In this work, sugarcane bagasse dried and carbonized in the oven at temperatures of 200, 325 and 450 °C were used as precursors of carbon dots using a solvothermal synthesis. The carbon-based fluorescent nanomaterial was tested as a fuel hydrated ethanol marker for possible fraud and adulteration prevention. In this way, the carbon spots produced were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, thermogravimetric analysis (TGA), absorption, emission and infrared spectroscopies. After the synthesis, the carbon dots showed blue fluorescence. The transmission electron microscopy showed nanoparticles with a spherical or almost spherical shape with sizes in the range from 1 to 5 nm for dry sugarcane bagasse and from 1 to 3.5 nm for carbonized sugarcane bagasse. These values were different from the sizes presented by DLS, which varied from 0.8 to5,560 nm. These results associated to the zeta potential results indicated the formation of nanoparticle aggregates occurred from the sample instability. On the other hand, the absorption spectra of the carbon points produced with the dried sugarcane bagasse and carbonized in the oven at 200°C showed a single broad band, different from what is seen in the literature, but within the ranges from 200 to 400 nm related to the carbon – carbon of the aromatic nucleus transition electronic and the functional groups bonds on the surface. The emission spectra of dry and carbonized sugarcane bagasse at 200 °C presented similar intensities, but with different full width at half maximum. For the carbonized bagasse it was 110 nm while that of the dried sugarcane bagasse was 85 nm. The carbon dots obtained from carbonized bagasse at 200 °C were excited at different wavelengths and showed dependence on the excitation wavelength, shifting their maximum intensity from 425 nm to 565 nm. The infrared spectra show that high temperatures remove the groups responsible for fluorescence on the surface of the nanomaterial, decreasing the fluorescence of carbon dots for the temperatures 325 °C and 450 °C. The goals of this work were achieved, considering that the carbon dots synthesized marked the ethanol fuel using absorption and fluorescence spectra. Although, the carbon dots produced with carbonized bagasse at 200 °C could only be detected in an order of magnitude above parts per million. This is beyond the concentration limit allowed by the Brazilian National Agency of Petroleum, Gas and Biofuels (ANP). 

BANKING MEMBERS:
Presidente - 2199290 - BEATE SAEGESSER SANTOS
Externo ao Programa - 1305873 - LUIZ STRAGEVITCH
Externa à Instituição - MÔNICA FREIRE BELIAN - UFRPE