Theoretical and experimental studies of benzoic acid batch adsorption dynamics using vermiculite-based adsorbent

In this article, the batch adsorption of benzoic acid from aqueous solution onto modified vermiculite was both experimentally and theoretically investigated. Mechanical modification of raw vermiculite was carried out by means of a laboratory vibratory disk mill. In addition, an organic modification was performed by cetyltrimethylammonium bromide. A set of experiments were conducted in order to optimize the adsorbent dosage, initial pH value and contact time and to evaluate the batch kinetics and the equilibrium isotherm. The Freundlich and the Toth isotherms best fitted our experimental data. A mathematical model was developed for the investigation of the adsorptive dynamic characteristics, thereby estimating the pore diffusivity based on the experimental results. The model showed a good agreement with the experiments and the effective diffusivity, the model adjustment parameter, was estimated as 0.33 x 10(-9) m(2) s(-1). (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.