ADSORPTION OF COBALT BY ACTIVATED CARBON FROM THE RICE HULLS

The removal of cobalt (II) ion from aqueous solutions, by adsorption o n activated carbon prepared from the rice hulls (ACRH), has been inves tigated depending on pH, activated carbon dosage, contact time, initia l metal concentration and solution temperature. The optimum values of pH, ACRH dosage and contact time have been determined as 6-7, 1.5 g AC RH/50 mt solution and 40 minutes respectively. Freundlich and Langmuir isotherm constants have been calculated at two different temperatures of 293 K and 313 K. Furthermore the other thermodynamic data for Delt a G degrees and Delta S degrees, have been also calculated at two temp eratures of 293 K and 313 K. The adsorption of Co (II) ion from aqueou s solutions has been found to be exothermic (Delta H degrees=-1.543 KJ /mol).