KINETIC AND THERMODYNAMIC STUDY OF CHLOROBENZENE ADSORPTION FROM AQUEOUS SOLUTIONS ONTO GRANULAR ACTIVATED CARBON

Abstract

The adsorption of chlorobenzene (CB) from aqueous solutions using granular activated carbon (GAC) of different particle sizes was studied at temperatures from 283 to 303 K. Experimental kinetic values were fitted to a hyperbolic expression, which corresponds to the pseudo-second-order kinetic model. The model predictions are satisfactory in the whole range of particle sizes. Adsorption was found to be governed by intraparticle diffusion. For the adsorption system studied, mass transfer resistance becomes low enough at particle sizes below 1.68 mm to allow an adequate intraparticle transport of solute to the adsorption sites on sorbent surface. Isotherm data were fitted to Langmuir, Freundlich and Redlich-Peterson models. The equilibrium uptake capacity increased with temperature, indicating the endothermic nature of the process. The apparent isosteric heat of adsorption was determined by means of the Clausius–Clapeyron equation being in the 88-288 kJ/mol range.