Remoção de fenol proveniente do óleo cru em água de mar por fotocatálise heterogênea utilizando catalisador de NiNb e Pt
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Data
2022-06-13
Autores
Costa, Kimberly Gomes da 
Orientadores
Asencios, Yvan Jesus Olortiga
Tipo
Dissertação de mestrado
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Título de Volume
Resumo
Durante o refino de petróleo é gerada a água produzida, que se define como a água associada ao óleo cru, e tem uma complexa composição química, contendo hidrocarbonetos aromáticos, óleos e graxas, sais, metais e gases dissolvidos. Sua presença é abundante, inevitável e seu tratamento é um desafio. Objetivo: O presente trabalho visa a síntese, caracterização do catalisador denominado NiNb com Platina depositada e a estudar sua aplicação na Fotocatálise heterogênea para degradar o fenol em água de mar. Métodos: O material foi sintetizado a partir do oxalato amoniacal de nióbio na presença de nitrato de níquel hexahidratado, resultando na heteroestrutura de Niobato de Sódio (NaNbO3/ NaNb3O8) e Óxido de Nível (NiO), com Platina depositada (Pt). O catalisador foi caracterizado por Difração de raios-X (DRX), Espectroscopia de Refletância Difusa (DRS), Microscopia Eletrônica de Varredura (MEV), Fluorescência de Raios X por Reflexão Total (TXRF), Espectroscopia de raios x por dispersão de energia (EDX) e Área superfícial BET (SBET). Foi testada a atividade fotocatalítica na degradação de um efluente fenólico modelo, de alta salinidade, similar às condições encontradas na água produzida do petróleo, na presença e na ausência de luz UV-C (germicida, de 254 nm), nos ensaios de remoção de fenol, alguns parâmetros como: dosagem de platina, pH da solução inicial e tempo de exposição à radiação foram analisados. Verificou-se também a reutilização do catalisador e o mecanismo fotocatalítico foi investigado por testes com agentes oxidantes. Resultados: As caracterizações do material confirmam a formação da heteroestrutura, resultando em material com características similares a outros materiais usualmente empregados em Fotocatálise, apresentando energia de band gap igual a 3,0 eV. Os resultados dos estudos fotocatalíticos, demonstraram que o catalisador NiNb/Pt, atingiu um desempenho melhor em água do mar, cerca de 65% de remoção de fenol e 57% em água destilada, em 5h de reação, ambos na presença de luz UV-C, comprovando que a alta salinidade e os derivados fenólicos formados, não comprometeram a atividade fotocatalítica. O catalisador foi empregado diferentes pH, porém a partir do pH 10 seu desempenho é afetado. Os estudos com espécies oxidantes demostraram que os radicais superóxido aniônicos (O2●−) e radicais hidroxila •OH têm mais influência na degradação do fenol, podendo assim verificar o mecanismo reacional. Conclusão: O catalisador proposto apresentou resultados adequados para o tratamento de águas com alta salinidade contaminadas com fenol, apesar do catalisador NiNb não ser por si só tão eficaz no processo de remoção, e ser necessária a adição de pequenas quantidades de platina, a reutilização do material sem adição de mais platina torna sua aplicação viável.
During petroleum refining, produced water is generated, which is defined as water associated with crude oil, and has a complex chemical composition, containing aromatic hydrocarbons, oils and greases, salts, metals and dissolved gases. Its presence is abundant and inevitable, its treatment is a challenge. Objective: The present work aims to synthesize and characterize the catalyst called NiNb with Platinum deposited and to study the application of heterogeneous photocatalysis to degrade phenol in seawater using the proposed catalyst. Methods: The material was synthesized from ammonium oxalate and niobium in the presence of nickel nitrate hexahydrate, resulting in the heterostructure of Sodium Niobate (NaNbO3/ NaNb3O8) and Level Oxide (NiO), with Platinum deposited ( PT). The catalyst was characterized by X-ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM), Total Reflection X-Ray Fluorescence (TXRF), Energy Scatter X-ray Spectroscopy (EDX) and Surface Area BET (SBET). The photocatalytic activity was tested in the degradation of a model phenolic effluent, of high salinity, similar to the conditions found in the water produced from petroleum, in the presence and absence of UV-C light (germicidal, 254 nm), in the tests of removal of phenol, some parameters such as: platinum dosage, pH of the initial solution and time of exposure to radiation were analyzed. The reuse of the catalyst was also verified and tests with oxidizing agents investigated the photocatalytic mechanism. Results: energy band gap equal to 3.0 eV. The results of the photocatalytic studies showed that the NiNb/Pt catalyst achieved a better performance in seawater, about 65% of phenol removal and 57% in distilled water, in 5h of reaction, both in the presence of UV light. C, proving that the high salinity and the phenolic derivatives formed did not compromise the photocatalytic activity. The proposed catalyst was to be used at different pH levels, but from pH 10 onwards its performance is affected. Studies with oxidizing species showed that anionic superoxide radicals (O2●−) and hydroxyl radicals •OH have more influence on phenol degradation, thus being able to verify the reaction mechanism. Conclusion: Based on what was exposed in this work, the proposed catalyst presented adequate results for the treatment of water with high salinity contaminated with phenol, although the NiNb catalyst is not as effective in the removal process by itself, and the addition of small amounts is necessary. platinum, reusing the material without adding more platinum makes its application viable.
During petroleum refining, produced water is generated, which is defined as water associated with crude oil, and has a complex chemical composition, containing aromatic hydrocarbons, oils and greases, salts, metals and dissolved gases. Its presence is abundant and inevitable, its treatment is a challenge. Objective: The present work aims to synthesize and characterize the catalyst called NiNb with Platinum deposited and to study the application of heterogeneous photocatalysis to degrade phenol in seawater using the proposed catalyst. Methods: The material was synthesized from ammonium oxalate and niobium in the presence of nickel nitrate hexahydrate, resulting in the heterostructure of Sodium Niobate (NaNbO3/ NaNb3O8) and Level Oxide (NiO), with Platinum deposited ( PT). The catalyst was characterized by X-ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM), Total Reflection X-Ray Fluorescence (TXRF), Energy Scatter X-ray Spectroscopy (EDX) and Surface Area BET (SBET). The photocatalytic activity was tested in the degradation of a model phenolic effluent, of high salinity, similar to the conditions found in the water produced from petroleum, in the presence and absence of UV-C light (germicidal, 254 nm), in the tests of removal of phenol, some parameters such as: platinum dosage, pH of the initial solution and time of exposure to radiation were analyzed. The reuse of the catalyst was also verified and tests with oxidizing agents investigated the photocatalytic mechanism. Results: energy band gap equal to 3.0 eV. The results of the photocatalytic studies showed that the NiNb/Pt catalyst achieved a better performance in seawater, about 65% of phenol removal and 57% in distilled water, in 5h of reaction, both in the presence of UV light. C, proving that the high salinity and the phenolic derivatives formed did not compromise the photocatalytic activity. The proposed catalyst was to be used at different pH levels, but from pH 10 onwards its performance is affected. Studies with oxidizing species showed that anionic superoxide radicals (O2●−) and hydroxyl radicals •OH have more influence on phenol degradation, thus being able to verify the reaction mechanism. Conclusion: Based on what was exposed in this work, the proposed catalyst presented adequate results for the treatment of water with high salinity contaminated with phenol, although the NiNb catalyst is not as effective in the removal process by itself, and the addition of small amounts is necessary. platinum, reusing the material without adding more platinum makes its application viable.
Descrição
Citação
COSTA, Kimberly Gomes da. Remoção de fenol proveniente do óleo cru em água de mar por Fotocatálise heterogênea utilizando catalisador de NiNb e Pt. 2022. 67 f. Dissertação (Mestrado Interdisciplinar em Ciência e Tecnologia do Mar) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2022.