Surface diffusion kinetics in the adsorption of acetic acid on activated carbon

The recovery of acetic acid from industrial wastewaters is an important separation problem, and one of the routes suggested for this application is liquid phase adsorption on activated carbon adsorbents. Designing an adsorber for such applications requires knowledge of equilibrium isotherm as well as adsorption rate data. In the present work the kinetics of adsorption of acetic acid on activated carbon has been studied. A three-parameter isotherm model has been used to correlate the equilibrium data, and a combined external film transfer-surface diffusion model has been used to simulate the experimental adsorption rate data. The surface diffusivity values obtained range from 6 to 8.5 x 10(-7) cm(2)/s, and the values show a dependence on surface loading. These surface diffusivity values can be used in modeling the column breakthrough behavior for this system.