Navegando por Assunto "Petróleo"

Agora exibindo 1 - 4 de 4

Avaliação da composição química de óleos de derramamentos por espectrometria de massas de ultra alta resolução
(2025-07-03) Salata, Ana Beatriz Alves de Miranda; Santos, Jandyson Machado; Pereira, Marília Gabriela Araújo; http://lattes.cnpq.br/4388998153970406; http://lattes.cnpq.br/4137257750865101; http://lattes.cnpq.br/2519974430606408
O petróleo é uma mistura química complexa composta predominantemente por hidrocarbonetos, que contém uma fração polar constituída por compostos com heteroátomos do tipo S, N e O. O petróleo desempenha um papel vital na economia global, sendo essencial como fonte de energia e matéria-prima industrial. No entanto, eventos de derramamentos de óleos representam uma séria ameaça a ambientes marinhos e costeiros, como ocorreu no desastre do ano de 2019 na costa nordestina do Brasil. Após um derramamento, o petróleo sofre processos físicos e químicos, como espalhamento, dissolução, evaporação, fotooxidação e biodegradação. Tais processos estão associados ao intemperismo do óleo no ambiente, que podem contribuir para o agravo da contaminação, devido a formação de novos constituintes químicos nocivos. Este estudo utilizou a abordagem em petroleômica para investigar óleos derramados coletados na costa de Pernambuco entre os anos de 2019 a 2021, com o objetivo de entender as alterações químicas dos compostos polares ao longo do tempo, devido à longa exposição do óleo a ambientes terrestres e aquáticos. Foram analisadas três amostras: SO (óleo coletado no primeiro mês do derramamento de 2019), SA (coletado após 16 meses em ambiente aquático marinho) e ST (coletado após 19 meses em ambiente terrestre costeiro). As análises foram realizadas por espectrometria de massas de ultra-alta resolução (FT-ICR MS) com ionização por electrospray nos modos ESI(+) e ESI(-). Por ESI(+), foram identificadas as classes N, NO, NO2, NS, O, O2S e OS, havendo pouca variação da intensidade delas quando comparadas as amostras entre si. Por ESI(-), maiores diferenças entre as amostras foram encontradas, sendo as principais classes: N, NO, O2, O3, O4, OS, e combinações de classes oxigenadas com enxofre (OS, O2S). Para a classe N, menores intensidades foram observadas nas amostras SA e ST, sugerindo degradação dos compostos nitrogenados, quando o óleo derramado ficou exposto ao ambiente aquático marinho ou terrestre, respectivamente. Em contrapartida, as classes Ox (x = 1 - 4) possui maiores intensidades em SA e ST, indicando que o óleo derramado sofreu processos de foto-oxidação e biodegradação nos ambientes. Razões entre classes heteroatômicas também foram calculadas, que apontaram o impacto do grau de biodegradação e foto-oxidação nas amostras SA e ST, quando comparadas a amostra do óleo derramado inicialmente (SO). Assim, os dados mostraram padrões distintos de compostos polares nas amostras, evidenciando a influência do intemperismo na modificação química dos óleos ao longo do tempo e em diferentes ambientes de exposição ambiental, fornecendo informações valiosas para entender o comportamento químico de óleos derramados a nível molecular.
Avaliação temporal de biomarcadores de petróleo empregados no estudo de derrames simulados em ambientes terrestres
(2019-07-09) Nascimento, Rayane Maria do; Santos, Jandyson Machado; http://lattes.cnpq.br/4137257750865101; http://lattes.cnpq.br/0803223548753880
Investigação das modificações químicas de biomarcadores de petróleo submetidos a derrames simulados em ambientes aquáticos
(2021-12-15) Oliveira, Milton Neto Nascimento de; Santos, Jandyson Machado; http://lattes.cnpq.br/4137257750865101; http://lattes.cnpq.br/4629247582941612
The oil industry characterizes a source of risks to the environment. Studies that aim to understand the chemical modification in oil spill situations are gaining greater attention due to recurrent environmental disasters, such as the one that occurred on the coast of Brazil in 2019. The purpose of this study was to apply a laboratory simulation of oil spills in aquatic environments, to evaluate the chemical changes in composition of oils using the technique of gas chromatography coupled to mass spectrometry (GC/MS) and infrared spectroscopy (IR). For the simulations, a homemade system was used that were a chamber with white, blue and ultraviolet lamps, referring to wavelengths like those emitted by solar radiation, where inside was allocated a mixture of oil and seawater 1:80 (m/v), and the oil spill simulation was performed to obtain aliquots of oil at different times of exposure. The oil aliquots were analyzed by GC/MS, in order to obtain a comparative analysis of the initial crude oil (control) and the same oil after the spill exposures, which was possible to evaluate the chemical changes of oil biomarkers and their diagnostic reasons. The chromatograms showed a decrease in the peak areas of the n-alkanes with lower molecular weight in the first hours of exposure to the simulated spill, however, no significant changes were observed in the diagnostic ratios for biomarkers of the sterane and terpane classes, showing that they are classes that do not change chemically. The IR was performed in the spectral range of 600-4000 cm-1, using attenuated total reflectance (ATR). The IR data showed peaks related to the majority chemical composition of crude oils, referring to aliphatic hydrocarbon compounds. It was also possible to identify peaks related to the appearance of new stretching linked to chemical changes associated with the photo-oxidation process that occurred in the spill simulation, referring to peaks for oxygenated compounds, in the region of 1233 cm-1. Thus, the study was able to identify some changes in the chemical composition of crude oils after simulated spills in aquatic environments, as well as to show that the consolidated diagnostic ratios involving terpanes and steranes do not change, and in both cases can be used in studies to track oil spills in environments and/or as data for remediation of environments impacted by spills involving the oil industry.
Isolamento de bactérias hidrocarbonoclásticas de sedimento de manguezal contaminado com petróleo
(2022-05-25) Paula, Nazareth Zimiani de; Lima, Marcos Antônio Barbosa de; http://lattes.cnpq.br/3887006042216258; http://lattes.cnpq.br/9977163727403212
In August of 2019, there was a petrol leakage which hit the shore of 11 states of the northeast and southeast of Brazil. This leakage affected several coastal ecosystems mainly estuary and mangrove forests, besides exposing coastal species already under threat. Mangrove forests are ecosystems extremely sensitive to contamination by hydrocarbons. Therefore, this present proposal has aimed at isolating and featuring hydrocarbonclastic bacteria with degradation potential in sediment of mangrove, contaminated by petrol, in Cabo de Santo Agostinho. To do so, samples of superficial sediments of mangrove which were contaminated, those were collected and submitted to the tests of quantification of total heterotrophic bacteria, assertiveness of hydrocarbonclastic bacteria, selection of isolated decomposers of petrol and by-products. The physical- chemical pH parameters, temperature, salinity, and conductivity were also measured in the sediment. It was not observed significant variation in the physical-chemical parameters among the variables analysed. On the other hand, It was obtained a total of 30 bacterial isolates, 15 heterotrophic and 15 hydrocarbonclastic bacteria. Negative Gram bacilli were predominant among heterotrophic and hydrocarbonclastic bacteria. Two isolated ones, the group of heterotrophic bacteria stood out. (isolated 1 & 4) due to showing more relative frequency, making up of 64 % of total isolated together. With regards to the 15 isolate hydrocarbonclastic bacteria, 13 of those, were obtained in the diesel oil environment as source for carbon. Of 15 isolate hydrocarbonclastic bacteria assessed, 10 displayed potential for decomposition of diesel oil, gasoline and kerosene. The isolate 7 was prominent as it achieved the best decomposition results of the 3 fuels analysed.