Potencialidade analítica de um silsesquioxano e uma sílica organofuncionalizados com imidazol
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Data
2012-08-03
Autores
Silveira, Tayla Fernanda Serantoni da [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
No presente trabalho, a 3-cloropropil sílica gel (SG) e o octa-(3-cloropropil)silsesquioxano (SS) foram preparados e organofuncionalizados com grupos imidazol e os materiais obtidos da funcionalização foram descritos como SGI e SSI, respectivamente. Os materiais funcionalizados foram preliminarmente caracterizados por técnicas tais como: espectroscopia na região do infravermelho (FTIR), difração de raios-X (DRX), microscopia eletrônica de varredura (MEV), além de análise de área superficial e porosidade para o precursor SG e o produto SGI. Foram realizados estudos de adsorção de íons metálicos (Cu2+ e Cd2+) para o SGI e SSI em diferentes meios, tais como: aquoso, etanol 42% e etanol 99%. Determinou-se o tempo de equilíbrio de adsorção para todos os meios e posteriormente, determinou-se a capacidade de adsorção (Nf) através de isotermas com diferentes concentrações molares dos íons metálicos, onde se observou que o SSI possui uma capacidade adsorvente maior que o SGI e ambos os adsorventes tem uma capacidade de adsorção maior para íons Cu2+ do que para os íons Cd2+. Os valores de Nf aumentaram de acordo com a seguinte ordem de solventes: água < etanol 42% < etanol 99%. Em uma segunda etapa do trabalho, após a adsorção dos íons metálicos (Cd2+ e Cu2+) pelo SGI e pelo SSI, reagiu-se os mesmos com ferricianeto de potássio (hexacianoferrato de potássio - HCF) formando-se assim os materiais CdHSGI, CuHSGI, CdHSSI e CuHSSI, respectivamente. Estes materiais foram caracterizados por espectroscopia na região do infravermelho (FTIR), difração de raios-X (DRX), espectroscopia na região do UV-visível (Reflectância difusa) e voltametria cíclica, além de serem testados na determinação eletrocatalítica de substâncias de interesse biológico. Foram realizados estudos voltamétricos da oxidação...
In the present work, 3-chloropropyl silica gel (SG) and octa-(3-chloropropyl)silsesquioxane (SS) were organofunctionalized with imidazole groups and the materials obtained of the functionalization were described as SGI and SSI, respectively. The functionalized materials were preliminarily characterized by very techniques such as: infrared spectroscopy (FTIR), X- ray diffraction (XRD), scanning electron microscopy (SEM), and also analysis of surface area and porosity for the precursor SG and the product SGI. Studies of adsorption were carried for metal ions (Cu2+ and Cd2+) for SGI and SSI in different media, such as: aqueous, ethanol 42% and ethanol 99%. It was determined the adsorption equilibrium time for all media and posteriorly, it was determined adsorption capacity (Nf) through isotherms with different molar concentrations of metal ions, where it was observed that SSI has an adsorption capacity greater than the SGI and both adsorbents have a superior adsorption capacity for ions Cu 2+ than ions Cd2+. The values of Nf increased according the following order of solvents: water < ethanol 42% < ethanol 99 %. After adsorption of metal ions (Cd2+ and Cu2+) by SGI and SSI, it was reacted with potassium ferricyanide (potassium hexacyanoferrate – HCF) thus forming the materials CdHSGI, CuHSGI, CdHSSI and CuHSSI, respectively. These materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), spectroscopy in the UV-visible (diffuse reflectance) and cyclic voltammetry and tested in the electrocatalytic determination of biologically important substances. Voltammetric studies of the electrocatalytic oxidation of ascorbic acid were carried out using CdHSGI and CdHSSI modified carbon paste electrodes, respectively. The CdHSGI modified electrode was sensitive to... (Complete abstract click electronic access below)
In the present work, 3-chloropropyl silica gel (SG) and octa-(3-chloropropyl)silsesquioxane (SS) were organofunctionalized with imidazole groups and the materials obtained of the functionalization were described as SGI and SSI, respectively. The functionalized materials were preliminarily characterized by very techniques such as: infrared spectroscopy (FTIR), X- ray diffraction (XRD), scanning electron microscopy (SEM), and also analysis of surface area and porosity for the precursor SG and the product SGI. Studies of adsorption were carried for metal ions (Cu2+ and Cd2+) for SGI and SSI in different media, such as: aqueous, ethanol 42% and ethanol 99%. It was determined the adsorption equilibrium time for all media and posteriorly, it was determined adsorption capacity (Nf) through isotherms with different molar concentrations of metal ions, where it was observed that SSI has an adsorption capacity greater than the SGI and both adsorbents have a superior adsorption capacity for ions Cu 2+ than ions Cd2+. The values of Nf increased according the following order of solvents: water < ethanol 42% < ethanol 99 %. After adsorption of metal ions (Cd2+ and Cu2+) by SGI and SSI, it was reacted with potassium ferricyanide (potassium hexacyanoferrate – HCF) thus forming the materials CdHSGI, CuHSGI, CdHSSI and CuHSSI, respectively. These materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), spectroscopy in the UV-visible (diffuse reflectance) and cyclic voltammetry and tested in the electrocatalytic determination of biologically important substances. Voltammetric studies of the electrocatalytic oxidation of ascorbic acid were carried out using CdHSGI and CdHSSI modified carbon paste electrodes, respectively. The CdHSGI modified electrode was sensitive to... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Silica gel, Adsorção
Como citar
SILVEIRA, Tayla Fernanda Serantoni da. Potencialidade analítica de um silsesquioxano e uma sílica organofuncionalizados com imidazol. 2012. 111 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Engenharia de Ilha Solteira, 2012.