Preparo, caracterização e utilização de folhas de Terminalia catappa Linn em procedimentos de extração em fase sólida de espécies metálicas em amostras aquosas
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Data
2018-07-23
Autores
Pereira, Gilmar Martins
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Universidade Estadual Paulista (Unesp)
Resumo
Os metais aqui estudados, Cd(II), Pb(II), Ni(II) e Cu(II) podem sofrer acumulação no meio ambiente através de sua capacidade de complexação com os organismos e adsorvidos em particulados e sedimentos. No ambiente, apesar da relativa baixa concentração, estas espécies podem sofrer bioacumulação e biomagnificação ao longo da cadeia trófica, manifestando toxicidade aos animais e plantas. Devido a baixa concentração em que estão presentes em amostras de águas naturais a tarefa envolvida na sua quantificação pode exigir técnicas de elevado custo, como por exemplo, espectrometria de absorção atômica com atomização em forno de grafite (GFAAS) e espectrometria de emissão óptica com plasma indutivamente acoplado (ICPOES) e espectrometria de massas com plasma indutivamente acoplado (ICPMS). Desta forma, o presente trabalho teve por finalidade obter um material adsorvente capaz de ser utilizado em sistemas de pré-concentração a partir de folhas de Terminalia catappa L., conhecida popularmente como chapéu de praia. O pó obtido a partir do tratamento das folhas foi caracterizado por espectroscopia na região do infravermelho (FTIR), ressonância magnética nuclear de 13C (RNM), medidas de área superficial específica pelo método BET e análise elementar de nitrogênio com o objetivo de identificar grupos capazes de adsorver as espécies metálicas sob investigação. Após caracterização, o material foi aplicado em estudos de adsorção para determinação da sua capacidade máxima, cinética e influência do pH da solução. Os dados obtidos dos experimentos cinéticos foram aplicados a diferentes modelos matemáticos teóricos que inferem que o mecanismo de remoção das espécies metálicas ocorre por quimissorção, por meio da formação de uma monocamada na superfície da partícula. Os resultados foram comparados com os dados obtidos com outros materiais (sintéticos e teóricos) e é possível, assim, comprovar seu bom funcionamento como adsorvente. Por fim, foi avaliado alguns aspectos que poderiam interferir na aplicação do material como, por exemplo, influência da vazão, concentração do eluente, volume de eluente e capacidade de reutilização do material. Os resultados obtidos, mostraram que a folha da Terminalia catappa apresenta grande potencial de adsorção, assim como outros materiais disponíveis na literatura como biosorventes. O material aqui estudado, se mostrou eficiente na aplicação de pré-concentração de espécies metálicas em solução aquosas.
The metals studied here, Cd (II), Pb (II), Ni (II) and Cu (II) can undergo environmental accumulation through their ability to complex with organisms and adsorbed on particulates and sediments. In the environment, alt hough the low voltage, these waves can undergo bioaccumulation and biomagnification al ong the trophic chain, manifesting toxicity to the animals and plants. (IC POES) and inductively coupled plasma mass spectrometry (ICPPE) and inductively co upled plasma mass spectrometry (GPOAS) and spectrometry of inductivel y coupled plasma (ICPOES) and inductively coupled plasma mass spectrometry (ICPMS ). In this way, the present project had to present a material capable of being used in systems of preconcentration of leaves of Terminalia catappa , popularly known as beach hat. The powder obtained from the treatment of the leaves was characterized by infrared spectroscopy (FTIR), 13C nuclear magnetic resonance (NMR), with measurem ents of surface determination by BET method and elemental nitrogen analysis with the aim of shaping groups of adsorb the metal species under investigation. After characterization, the material was applied in adsorption studies to determine its maxi mum capacity, kinetics and pH influence of the solution. The data of the experime nts were applied to different theoretical mathematical models that infer that the mechanism of removal of the metallic species occurs by chemisorption, through t he formation of a monolayer on the surface of the particle. Tests were compared with t he data obtained with the other materials (synthetic and theoretical) and it is pos sible to prove its good functioning as an adsorbent. Finally, it has been validated a few times that they interfere with the application of the material, such as the influence of flow, eluent concentration, eluent volume and reusability of the material. The results obtained, in comparison to the Terminalia catappa , present great adsorption potential, as well as ot her materials available in the literature as biosorbents. The mat erial studied here has become efficient in preconcentration applications of metal lic species in aqueous solutions.
The metals studied here, Cd (II), Pb (II), Ni (II) and Cu (II) can undergo environmental accumulation through their ability to complex with organisms and adsorbed on particulates and sediments. In the environment, alt hough the low voltage, these waves can undergo bioaccumulation and biomagnification al ong the trophic chain, manifesting toxicity to the animals and plants. (IC POES) and inductively coupled plasma mass spectrometry (ICPPE) and inductively co upled plasma mass spectrometry (GPOAS) and spectrometry of inductivel y coupled plasma (ICPOES) and inductively coupled plasma mass spectrometry (ICPMS ). In this way, the present project had to present a material capable of being used in systems of preconcentration of leaves of Terminalia catappa , popularly known as beach hat. The powder obtained from the treatment of the leaves was characterized by infrared spectroscopy (FTIR), 13C nuclear magnetic resonance (NMR), with measurem ents of surface determination by BET method and elemental nitrogen analysis with the aim of shaping groups of adsorb the metal species under investigation. After characterization, the material was applied in adsorption studies to determine its maxi mum capacity, kinetics and pH influence of the solution. The data of the experime nts were applied to different theoretical mathematical models that infer that the mechanism of removal of the metallic species occurs by chemisorption, through t he formation of a monolayer on the surface of the particle. Tests were compared with t he data obtained with the other materials (synthetic and theoretical) and it is pos sible to prove its good functioning as an adsorbent. Finally, it has been validated a few times that they interfere with the application of the material, such as the influence of flow, eluent concentration, eluent volume and reusability of the material. The results obtained, in comparison to the Terminalia catappa , present great adsorption potential, as well as ot her materials available in the literature as biosorbents. The mat erial studied here has become efficient in preconcentration applications of metal lic species in aqueous solutions.
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Palavras-chave
Adsorção, Dessorção, Biossorção