Navegando por Assunto "Surface modification"

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Modificação da superfície de carvão ativado comercial (CAG) para a aplicação na adsorção de benzeno e tolueno
(Universidade Federal do Pará, 2012-09-28) LOPES, Anna Sylmara da Costa; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219
In this work they were studied the characteristics of surface of CAG commercial in natura (CA-1) and treated for (HNO3) (CA-2) and their applications in the adsorption of benzene and tolueno. Characterization of the adsorventes: specific superficial area - SBET and distribution of pores (adsorption of N2/77 K), pH (norm ASTM D3838-05), functional groups of surface (FTIR and method of Boehm). Adsorption tests were performed in batch system and fixed bed column (25 ° C/140 rpm/25 minutes), where the samples were quantified by gas chromatography with headspace extraction by EPA method 0010. The SBET and the average volume of the pores of the adsorbent CA-2 decreased with relation to the values of CA1 as well as the pH. There was an increase of acidic functional groups determined by the method Boehm of the adsorbent CA-2 in relation to CA-1, which was confirmed by determining FTIR, in which the intensity of the absorption bands were more intense for CA-2. Test data were fitted satisfactorily by kinetic mathematical model of pseudo-second order, based on statistical tests applied, with statistically significant differences between the treated adsorbent (CA-2) and in natura (CA-1). Assays were performed equilibrium adsorption, and the results correlated by the Langmuir isotherm, with satisfactory response for that model. From the adsorption system in a fixed bed column and considering the highest volumetric flow (Q = 100 mL / min) used in this system yielded the most important results of adsorption of benzene and toluene using (CA-2) as adsorbent.