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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

[pt] CARACTERIZAÇÃO DE MARCADORES MOLECULARES E USO DE DIFERENTES PROXIS PARA ESTUDO DO REGISTRO DE COMBUSTÃO EM SEDIMENTO NA AMAZÔNIA CENTRAL (COARI-MANAUS) / [en] CHARACTERIZATION OF MOLECULAR MARKERS AND USE OF DIFFERENT PROXIS FOR STUDY OF THE REGISTER OF COMBUSTION IN SEDIMENT IN THE CENTRAL AMAZON (COARI-MANAUS)

TEREZA CRISTINA SOUZA DE OLIVEIRA 11 October 2007 (has links)
[pt] A Amazônia, região de interesse desse estudo, apresenta muitas características particulares que justificam investigações mais detalhadas sobre a composição de marcadores moleculares em seu ambiente. Apeser da importância de sua biodiversidade e reservas de água doce, a Amazônia vem sofrendo redução de área verde pela ocorrência de queimadas e desmatamentos. No Amazonas, o rio Solimões tem um papel importante quanto à navegação, pois é a única via de acesso a vários municípios no Estado, além de ser rota de transporte para a indústria do petróleo na região. Tais atividades apresentam potencial de impacto, o qual pode ser melhor compreendido se houver a caracterização antecipada dos hidorcarbonetos para inferir sobre diferentes origens de compostos no sedimento. A ocorrência de queimadas em larga escala, principalmente no Pará e sul de Rondônia, em siturações atmostéricas favoráveis, contribui para o conjunto desses marcadores. Este trabalho foi realizado dentro da área de atuação do projeto PIATAM III (Potenciais Impactos e Riscos Ambientais da Industria do Petróleo e Gás no Amazonas), o qual é um projeto multidisciplinar de monitoramento das áreas de atividade da Petrobrás. O PIATAM atua em um percurso de 400 km ao longo do rio Solimões, no trecho das cidades Coari (S03 39, W63 33) - Manaus (S03 05, W60 03). As coletas de sedimento superficial foram realizadas no período de cheia (jun-2005, coleta I) e de seca dos rios (nov-2005, coleta II). Nesta coleta II, também foi realizada amostragem de perifl de sedimento em três lagos. Foram, ainda, coletadas amostras de sedimento superficial da área industrial de Manaus. Nesses sedimentos foi realizado analises de hidrocarbonetos saturados, aromáticos e metais traços. Além desses parâmetros, também foram determinados: carbono orgânico, granulometria, pH, Eh e realizada a datação de 210Pb nos perfis de sedimento. Os compostos analisados foram os hidrocarbonetos saturados, os hidrocarbonetos policíclicos aromáticos (HPAs) e outros marcadores moleculares, e ainda, alguns organoclorados. Utilizou-se a cromatografia gasosa CG-DIC e CGEM nestas determinações, e os metais foram analisados por ICP- MS e OES. Os resultados mostraram que os sedimentos no trecho Coari- Manaus apresentam níveis de compostos orgânicos com grande variabilidade entre as estações, no entanto, abaixo dos níveis de referência estabelecidos pelas agências de controle ambiental. As concentrações foram de 0,82 a 148 (mi)g g(-1) para hidrocarbonetos saturados e 52 a 774 ng g(-1) para a soma de 38 HPAs. Cd apresentou as menores concentrações com um máximo de 1,33 (mi)g g(-1) e Zn foi o elemento de maior intensidade com um máximo de 147 (mi)g g(-1). Para os organoclorados, apenas pp DDE e pp DDD foram encontrado a níveis traço. As concentrações de hidrocarbonetos e metais obtidas na área industrial foram sempre mais elevadas, retratando um ambiente contaminado. Os sedimentos, no trecho Coari-Manaus, apresentam predominantemente hidrocarbonetos de origem biogênica. A identificação de compostos derivados de precursores biogêncicos (a-amerina, b- amerina e lupeol) foi realizada pela análise de biomarcadores. O cálculo de índices de diagnóstico, as análises estatísticas (PCA, Spearman) e as investigações de biomarcadores, confirmaram a contribuição para o conjunto de hidrocarbonetos aromáticos da combustão de biomassa ocorrida na floreta Amazônica. A avaliação de perfis de sedimento mostrou a tendência evolutiva, pelo estudo geocronológico, de fontes de combustão de biomassa e evidenciam características de processos de diagênese recente. / [en] Amazon, the studied area in this work presents many relevant characteristics, so that it requires more detailed inquiries about molecular markers composition in its environment. Despite of great importance of its biodiversity and freshwater reservoirs, the Amazon basin has been suffering with reduction of its green area due to forest fires and deforestation. In the Amazon basin, the river Solimões has an important role for navigation, because it is the only way to get to some cities. Besides, it is the major transportation route for the oil industry settled in that region. For these reasons it is understood the utter importance to perform characterization of molecular markers for inferring different composition origins in sediment. This work was carried out inside of the studied area of PIATAM III Project (Potential Impacts and Environmental Risks of the Industria of the Oil and Gas in Amazon), a relevant multidisciplinary project of Petrobras. The PIATAM acts along 400 km of the river Solimões, between the cities Coari (S03 39 , W63 33) and Manaus (S03 05 , W60 03). Superficial sediment sampling were conducted during flood (June 2005, Sampling I) and dry seasons (November 2005, Sampling II). During Sampling II, it was also sampled sediment profiles in three lakes. Superficial sediment samples from industrial area of Manaus were analyzed for results comparison. In these sediments, analyses were carried for saturated and aromatic hydrocarbons, and trace metals. Beside these parameters, the following complementary data were also analyzed: organic carbon, grain size, pH, Eh and 210Pb dating for the sediment profiles. Extractions for organic compounds were performed by Soxhlet (EPA3540C), cleanup by liquid chromatographic (EPA 3510). Sediment extracts were analyzed by GC-FID (saturated hydrocarbons) (EPA3630), GC-MS (PAHs and biomarkers) (EPA-8270D) and CG-ECD (organochlorides) (modified UNEP71). Trace metal analyses were performed by ICP-MS and ICP-OES. Results of this work have shown that sediments from Coari- Manaus stretch presented great variability for levels of organic pollutants. However, they were below of reference levels established by environmental agencies. Concentrations varied from 0.82 to 148 ug g-1 for saturated hydrocarbons and from 52 to 774 ng g-1 for total polycyclic aromatic hydrocarbons (PAH). For metals, Cd presented the lowest concentrations and a maximum value of 1.33 (mi)g g(-1). Zn was the element with the highest intensity with a maximum value of 147.3 (mi)g g(-1). Among organochlorine pesticides, results only for pp DDE and pp DDD were found at trace levels. The concentrations obtained in the industrial area were in all cases the highest ones, indicating a contaminated environment. Sediments from the Coari-Manaus stretch, presented hydrocarbons mainly from biogenic sources. The compound identification from biogenic precursors (a-amyrin, b-amyrin e lupeol) was performed by analyses of biomarkers. The calculation of diagnostic indexes, the statistical analyses (PCA, Spearman) and the investigation of biomarkers have confirmed that part of the input by biogenic sources is a consequence of biomass combustion contribution due to fires in the Amazon area. Some sediment core results revealed not only the evolution trend for sources of biomass combustion, but also the characteristics of recent diagenetic processes.
2

MASS SPECTROMETRY IONIZATION STUDIES AND METHOD DEVELOPMENT FOR THE ANALYSIS OF COMPLEX MIXTURES OF SATURATED HYDROCARBONS AND CRUDE OIL

Jeremy M Manheim (6594134) 17 April 2020 (has links)
<p>Crude oil is a mixture of hydrocarbons so complex that it is predicted to comprise as many compounds as there are genes in the human genome. Developing methods to not only recover crude oil from the ground but also to convert crude oil into desirable products is challenging due to its complex nature. Thus, the petroleum industry relies heavily on analytical techniques to characterize the oil in reservoirs prior to enhanced oil recovery efforts and to evaluate the chemical compositions of their crude oil based products. Mass spectrometry (MS) is the only analytical technique that has the potential to provide elemental composition as well as structural information for the individual compounds that comprise petroleum samples. The continuous development of ionization techniques and mass analyzers, and other instrumentation advances, have primed mass spectrometry as the go-to analytical technique for providing solutions to problems faced by the petroleum industry. The research discussed in this dissertation can be divided into three parts: developing novel mass spectrometry-based methods to characterize mixtures of saturated hydrocarbons in petroleum products (Chapters 3 and 5), exploring the cause of fragmentation of saturated hydrocarbons upon atmospheric pressure chemical ionization to improve the analysis of samples containing these compounds (Chapter 4), and developing a better understanding of the chemical composition of crude oil that tightly binds to reservoir surfaces to improve chemically enhanced oil recovery (Chapter 6). </p>

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