Prediction of chlorophenols adsorption on activated carbons by representative pores method
José Carlos Alexandre de Oliveira1, Paulo Ricardo Moura Rodrigues1, Sebastião Mardônio Pereira de Lucena2
1Laboratory of Modeling and 3D Visualization, GPSA, Department of Chemical Engineering, Universidade Federal do Ceará, Campus do Pici, bl 709, Fortaleza, CE, 60455-760, Brazil.
Abstract:
The specification of a particular activated carbon adsorbents for removal of phenol and related derivatives, from dilute aqueous solutions, is still based on lengthy trial and error experimental tests. A predictive model of adsorption of these compounds would considerably reduce the carbon selection time and could also bring new information to support more efficient carbon synthesis. The use of molecular simulation and the methodology of representative pores proved to be adequate for quantitative prediction of phenol adsorption. Here the methodology is being extended to chlorophenols, an important class of phenol-derived pollutants. A set of ortho- and para-chlorophenol isotherms were simulated for different representative pores in order to predict carbon adsorption and determine the most significative pore size. At low concentrations (1 × 10-4 mol/L), the pores of 8.9 and 18.5 Å are the most effective. For concentrations above 3 × 10-4 mol/L, pores in the range of 27.9 Å must be present in the activated carbon. The simulation predicts a step for the 27.9 Å pore that can be correlated with experimental steps in literature. Finally, the adsorption isotherms of chlorophenols for other activated carbons were predicted with the help of the model.
