Extração de poluentes orgânicos e inorgânicos pela vermiculita magnética & desenvolvimento de sensor eletroquímico mip para 1-naftol presentes na água produzida de petróleo
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2019-12-16
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Universidade Estadual Paulista (Unesp)
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A extração de petróleo é uma das práticas mais importantes para obtenção de produtos como gases e combustíveis com demanda mundial crescente, assim como a geração de águas residuais provenientes deste processo. Também denominadas “águas produzidas de petróleo” (APP), essas águas contêm poluentes dissolvidos tóxicos e mutagênicos necessitando removêlas e detectá-las utilizando métodos analíticos eficientes os quais são de difícil desenvolvimento devido à alta complexidade da amostra contaminada com gases, óleos dissolvidos, sais, metais e diversos aromáticos danosos ao ambiente e organismos vivos em baixas concentrações tais como benzeno, tolueno, etilbenzeno e xilenos (BTEX), hidrocarbonetos poliaromáticos (PAH), assim como seus derivados e subprodutos provenientes de processos oxidativos. Neste trabalho, a vermiculita modificada com nanopartículas de magnetita (Fe3O4) foi investigada como adsorvente para extração de compostos orgânicos e metais dissolvidos nesta amostra. O material foi caracterizado por imagens de Microscopias eletrônicas de varredura e de transmissão (TEM), padrões de difração provenientes do Difratogramas de raio-X e por difração de elétrons em área selecionada pelo equipamento TEM, áreas superficiais BET e comportamentos magnéticos por Magnetometria de amostra vibrante. A exposição do mineral magnetizado à APP apresentou redução de 97 % do carbono orgânico total dissolvido após 5 min de exposição e estabilidade à dessorção, assim como análises por Cromatografia gasosa acoplada ao espectrômetro de massas mostraram redução de até 85 % de compostos BTEX e diminuição de até 67 % de metais entre Pb, Ba, Al, Cu, Ag e Hg, estes detectados por Espectrometria de massa com plasma acoplado indutivamente. Considerando a dificuldade de análise de compostos voláteis como naftaleno, também foi desenvolvido um sensor eletroquímico para detecção do poluente 1-naftol (1- Ph), subproduto majoritário da fotodegradação deste poluente PAH. Ele foi construído pelo método de polímero molecularmente impresso com a eletropolimerização da o-fenilenodiamina em eletrodo de carbono vítreo e analisado indiretamente pelo comportamento redox do íon complexo ferri/ferrocianeto como sonda voltamétrica. Sob otimizadas condições da resposta eletroquímica por análise de voltamogramas de pulso diferencial, uma curva analítica linear foi construída no intervalo de 5,0 10-9 a 2,5 10-8 mol L-1 de 1-Ph com limite de detecção de 1,47 10-9 mol L-1 e alta sensibilidade amperométrica. O MIP eletroquímico também apresentou alta seletividade baseada na baixa interferência de fenol, tolueno, naftaleno e fluoranteno na presença de 1-Ph. Assim, nessa faixa de concentração, o método de adição de padrão foi empregado para quantificação de 1-Ph na amostra baseado na construída curva com porcentagens de recuperação próximas a 100% o que atribui confiabilidade ao método analítico empregado.
The extraction of oil is one of the most important practices for obtaining productssuch as gases andfuelswhich is growing world’s needsas well as the rising amount of residual waterrelated to this process. It isalso called“oilfield produced water”(OPW)which containsmutagenic and toxicdissolved pollutantswhat demand extracting and detecting those by efficient analytical methods which are difficult to be developedbase onthe high complexityof the samplethat is contaminated with gases, dissolved oils, salts, metalsand a variety of aromatics–such as benzene, toluene, ethylbenzene, xylenes (BTEX), polyaromatic hydrocarbons (PAHs), as well as their byproducts from oxidative processes –at low concentrations still even harmful for the environment and living organisms.This study investigated the vermiculite with magnetite nanoparticles (Fe3O4) as ad-sorbent for the extraction of the dissolved substances as organic compounds and metals in this type sample.The material was characterized by images of scanning and transmission (TEM) electron microscopies, BET superficial areas, diffraction patters using X-ray diffractometer and TEM mode called Selected areaelectrondiffraction, and magnetic behavior by Vibrating sample magnetometry. The exposure of the magnetized mineral to the OPWpresented a reduction of 97% of the total dissolved organic carbon after 5 minutes of exposure and stability to desorptionand Gas chromatography-mass spectrometry analyses showed a reduction of up to 85% in the BTEX compounds;and also promoted a reduction of up to 67% of metalsPb, Ba, Al, Cu, Ag and Hg detectedand quantified by Inductively coupled plasma mass spectrometry. Considering the complexity of the analysis of volatile compounds such as naphthalene, an electrochemical sensor wasalsodeveloped in order to detect 1-naphthol (1-Ph), a major byproduct of the photodegrada-tion of this PAH pollutant. It was built by using the molecularly imprinted polymer method with the electropolymerization of the o-phenylenediamine in glassy carbon electrodeand analyzed indi-rectly by redox behavior of complex ion ferri/ferrocyanide asthe voltammetric probe.Underopti-mized electrochemical conditions by analysis of differentialpulse voltammograms, linear analyti-cal curvewasbuilt within the interval of5,0 10-9to 2,5 10-8mol L-1of 1-Ph, with detection limit 1,47 10-9mol L-1and high amperometric sensitivity. The electrochemical MIPhas also shown high selectivity base onlow interference of phenol, toluene, naphthalene and fluoranthenewith presenceof 1-Ph. Thus, within this concentration range, the standard addition method was used to quantify 1-Ph in the sample based on the generated curve which reached recovery percent-ages close to 100% what makes the analytical method reliable.
The extraction of oil is one of the most important practices for obtaining productssuch as gases andfuelswhich is growing world’s needsas well as the rising amount of residual waterrelated to this process. It isalso called“oilfield produced water”(OPW)which containsmutagenic and toxicdissolved pollutantswhat demand extracting and detecting those by efficient analytical methods which are difficult to be developedbase onthe high complexityof the samplethat is contaminated with gases, dissolved oils, salts, metalsand a variety of aromatics–such as benzene, toluene, ethylbenzene, xylenes (BTEX), polyaromatic hydrocarbons (PAHs), as well as their byproducts from oxidative processes –at low concentrations still even harmful for the environment and living organisms.This study investigated the vermiculite with magnetite nanoparticles (Fe3O4) as ad-sorbent for the extraction of the dissolved substances as organic compounds and metals in this type sample.The material was characterized by images of scanning and transmission (TEM) electron microscopies, BET superficial areas, diffraction patters using X-ray diffractometer and TEM mode called Selected areaelectrondiffraction, and magnetic behavior by Vibrating sample magnetometry. The exposure of the magnetized mineral to the OPWpresented a reduction of 97% of the total dissolved organic carbon after 5 minutes of exposure and stability to desorptionand Gas chromatography-mass spectrometry analyses showed a reduction of up to 85% in the BTEX compounds;and also promoted a reduction of up to 67% of metalsPb, Ba, Al, Cu, Ag and Hg detectedand quantified by Inductively coupled plasma mass spectrometry. Considering the complexity of the analysis of volatile compounds such as naphthalene, an electrochemical sensor wasalsodeveloped in order to detect 1-naphthol (1-Ph), a major byproduct of the photodegrada-tion of this PAH pollutant. It was built by using the molecularly imprinted polymer method with the electropolymerization of the o-phenylenediamine in glassy carbon electrodeand analyzed indi-rectly by redox behavior of complex ion ferri/ferrocyanide asthe voltammetric probe.Underopti-mized electrochemical conditions by analysis of differentialpulse voltammograms, linear analyti-cal curvewasbuilt within the interval of5,0 10-9to 2,5 10-8mol L-1of 1-Ph, with detection limit 1,47 10-9mol L-1and high amperometric sensitivity. The electrochemical MIPhas also shown high selectivity base onlow interference of phenol, toluene, naphthalene and fluoranthenewith presenceof 1-Ph. Thus, within this concentration range, the standard addition method was used to quantify 1-Ph in the sample based on the generated curve which reached recovery percent-ages close to 100% what makes the analytical method reliable.
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Água - Poluição por petróleo, Contaminantes emergentes na água, Vermiculita, Análise eletroquímica, Polímeros impressos