Logo PUC-Rio Logo Maxwell
ETDs @PUC-Rio
Estatística
Título: GEOCHRONOLOGICAL VARIATIONS OF CARBON BLACK AND PAHS IN GUANABARA BAY AS INDICATORS OF COMBUSTION SOURCES
Autor: CRISTIANE RIBEIRO MAUAD
Colaborador(es): ANGELA DE LUCA REBELLO WAGENER - Orientador
Catalogação: 26/NOV/2010 Língua(s): PORTUGUESE - BRAZIL
Tipo: TEXT Subtipo: THESIS
Notas: [pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
[en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio.
Referência(s): [pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=16588&idi=1
[en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=16588&idi=2
DOI: https://doi.org/10.17771/PUCRio.acad.16588
Resumo:
Researches about black carbon (BC) have been gaining importance in recent years, not only because of its ability to act as a tracer of historical combustion processes in a given region, but also for its ability to adsorb hydrophobic contaminants in aqueous environments. In a sediment core collected from the northwestern region of Guanabara Bay, was attempted to study the geochronology of two combustion sub-products processes (BC and PAHs - polycyclic aromatic hydrocarbons), which may originate both biomass burning and fossil fuels. Was evaluated their possible relationships between themselves and with the content of organic carbon in the sediment. Also was evaluated the possible PAHs sources in the samples, tracing a burning history in the region, characterized by a marked vehicular traffic pollution and chronic individual compounds. The core was sectioned at intervals of 2 cm, which were used from 0 to 72 cm segments, in a total of 30 samples. The BC analytical determination methodology was the CTO-375, based on organic matter (non-BC) removal by combustion in presence of excess oxygen, leaving only a fraction composed by most refractory BC. Although the BC percentage had an average of 0.36 (+-) 0.08% dry weight over the core, was observed that is a significant fraction of total organic carbon (TOC) in this place representing up to 18% d.w. of TOC. The C/N ratio permitted evaluate that much of organic matter on this site comes from sea sources. The method used for determining the concentration of PAHs was the EPA 3540C, based on the analytes extraction from the matrix, and the extracts purification through the interferences removal. Through diagnostic reasons and principal component analysis (PCA), were possible to evaluate a PAHs transition of the main sources in this environment, showing the PAHs predominance in older pirogenics samples to an increase of petrogenic contamination in the most recent samples. It was also possible to relate an affinity of PAHs pyrogens in the BC presence. Analysis of scanning electron microscopy (SEM) contributed to a better understanding about the sediment morphological characteristics, showing to be rich in amorphous material and centric diatoms. This analysis also allowed the visual identification of the BC particles, however, the lack of a pre-treatment in the samples made it difficult to recognize. Nuclear magnetic resonance (CP/MAS (13)C NMR) analysis were performed in order to future possibilities of BC determination by this technique. The NMR analysis showed that the high aromatic carbon content in the environment sample, is mainly related to the presence of lignin interferes with the signal of NMR for the determination of BC, which requires its oxidation. Analysis of CP/MAS-NQS (13)C NMR allowed the separation of fractions of BC, showing a strong level of carbon non-replaced, suggesting a greater contribution of BC from burning during the core. In the most superficial sample, it was observed the large presence of quaternary carbons, indicating an increase in the input of BC come from combustion of fossil fuels.
Descrição: Arquivo:   
COVER, ACKNOWLEDGEMENTS, RESUMO, ABSTRACT, SUMMARY AND LISTS PDF    
CHAPTER 1 PDF    
CHAPTER 2 PDF    
CHAPTER 3 PDF    
CHAPTER 4 PDF    
CHAPTER 5 PDF    
CHAPTER 6 PDF    
CHAPTER 7 PDF    
CHAPTER 8 PDF    
REFERENCES AND ANNEX PDF