Apparent desorption kinetics of phenol in organic solvents from spent activated carbon saturated with phenol

This paper presents the result of an experimental work designed to develop a desorption kinetic model of phenol from activated carbon (AC) by acetone, NN-dimethylformamide (DMF), and methanol. The kinetic model assumed that a driving force for desorption might be accounted for by the difference between the equilibrium concentration of phenol in solvents corresponding to its adsorbed amount on AC and the bulk phenol concentration in solvents at a time. The equilibrium concentration of phenol in solvents was estimated from a non-linear relationship with its adsorbed amount on AC at a time. Apparent desorption rate constants were described as a function of temperature by Arrhenius relationship. Desorption rate of phenol increased with desorption temperature of solvents. The desorption rates attained by acetone and DMF were close each other but greater than those by methanol. Theoretical kinetic results duplicated experimental data quite well, supporting the practicality of the proposed kinetic model. Acetone and DMF were found to be more efficient for desorbing phenol from AC than methanol. (C) 2004 Elsevier B.V. All rights reserved.