SURFACE-DIFFUSION KINETICS IN THE ADSORPTION OF ACETIC-ACID ON ACTIVATED CARBON

The recovery of acetic acid from industrial wastewaters is an importan t separation problem, and one of the routes suggested for this applica tion is liquid phase adsorption on activated carbon adsorbents. Design ing an adsorber for such applications requires knowledge of equilibriu m isotherm as well as adsorption rate data. In the present work the ki netics of adsorption of acetic acid on activated carbon has been studi ed. A three-parameter isotherm model has been used to correlate the eq uilibrium data, and a combined external film transfer-surface diffusio n model has been used to simulate the experimental adsorption rate dat a. 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 breakthr ough behavior for this system.