Adsorption and desorption studies in the aqueous phase for the toluene/activated carbon system

Abstract

AbstractThe activated carbon adsorption and desorption of toluene in single‐component aqueous solutions were investigated. Adsorption equilibrium and batch rate studies were conducted to measure the capacity of Filtasorb‐300 (F‐300) for toluene and to determine the effects of the initial toluene concentration, the F‐300 particle size, and the hydrodynamic conditions in the liquid phase on the rate of toluene adsorption on F‐300. The results of the adsorption rate experiments were successfully fitted with the homogeneous surface diffusion (HSD) model and a surface diffusion coefficient which varies exponentially with surface coverage. The model also accounted for the dependence of the external toluene mass transfer coefficient on the hydrodynamic conditions in the liquid phase. The reversibility of toluene adsorption on F‐300 was addressed in desorption equilibrium experiments which indicated that only about five percent of the toluene molecules adsorb irreversibly on the surface of F‐300. Batch desorption rate studies were conducted for different initial toluene surface concentrations, F‐300 particle sizes, and liquid/solid ratios. Use of the previously determined toluene transport parameters in the HSD model allowed for successful prediction of the experimental desorption rates.