Kinetic studies on the adsorption of phenol from aqueous solution by coffee husk activated carbon

The kinetics of phenol adsorption from aqueous solution on activated carbons (ACs) obtained from coffee husk by potassium Hydroxide (KOH) activation at 650 and 750 o C have been studied in the range of     100-250 mg L -1 initial phenol concentrations and at the temperatures range of 10 – 40 o C. Kinetic models for phenol adsorption were evaluated using pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption mechanism was investigated using Reichenberg, Boyd, and Weber and Morris models. The adsorption on coffee husk activated carbon was found to be a fast or speedy process with the adsorption rate, k 2 q e , in the range of 0.130 to 0.977 min -1 . The adsorption process was mainly physical and promoted by chemical sorption and controlled not only by intra-particle diffusion but also by pore diffusion throughout the entire adsorption period.