Síntese e caracterização de carbono polimérico para remoção de atrazina por adsorção

Abstract

This work describes the synthesis and characterization of polymeric carbon produced from the catalytic graphitization of phenolic resin and its use as adsorbent material to atrazine removal. Four different samples of carbon materials were obtained and synthesized with different levels of agitation in the step of mixing the graphitization catalyst (ferrocene) with prepolymer. The carbon samples were characterized by X-Ray Diffraction (XRD), Raman Spectroscopy and surface area, pore size and pore morphology by BET. The XRD and Raman Spectroscopy results showed that samples are formed by a mixture of graphitic and non-graphitic carbon and a mixture of Fe oxides. All samples have high surface area and average pore size compatible with ATZ molecule size. The preliminary results of ATZ adsorption showed that magnetic stirring interferes in the adsorptive potential of the samples due to their magnetic property, and therefore the use of this method of stirring is unfeasible. There wasn't significant difference in the adsorption capacity of ATZ when mechanical agitation was used or when the pH of system was varied. The ATZ adsorption kinetics followed the pseudo-second order model and the Weber and Morris model showed that adsorption occurs by external mass transfer and intraparticle diffusion, corroborating the adjusted kinetic model. With the increase in temperature, there was an increase in the adsorption capacity of ATZ, which reached 451.6 mg.g-1 at 50 ºC. The Langmuir isotherm model was the most adequate to represent the equilibrium experimental data and the thermodynamic study indicated that the adsorption of ATZ on CPAG4 was spontaneous, favorable, physical, endothermic and entropy controlled. The ferromagnetic property of the material is an attractive of great differential that can facilitate and enable the process of separation and its reuse, in addition, the material studied has excellent prospects for being used as an adsorbent in the removal of other contaminants, anions and cations, due to the high surface area and the predominance of different charges varying the pH of the system.