Kinetic, equilibrium and thermodynamic study of 2-chlorophenol adsorption onto Ricinus communis pericarp activated carbon from aqueous solutions

This study reports on the adsorption of 2-chlorophenol from an aqueous solution using activated carbon prepared by H2SO4 activation of the pericarp of Ricinus communis (RCAC). The pericarp was carbonized and activated by treating with H2SO4 solution followed by heating in an oven at 105 degrees C for 12 hrs. Batch adsorption experiments were carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage and temperature of the solution. Kinetic data were best fit to a pseudo-first-order rate equation for the adsorption of 2-chlorophenol on RCAC. Thermodynamic parameters H-o, S-o and G(o) for the adsorption were also determined which shows that adsorption on the surface of RCAC was spontaneous in nature, and exothermic between temperatures of 20 degrees C and 80 degrees C. The equilibrium data better fit the Langmuir isotherm model for 2-chlorophenol adsorption on RCAC. IR spectrum for loaded and unloaded RCAC was obtained and found to be in good agreement.