Thermodynamic Study of Fe+3, Cr+3 and Cd+2 Ions Adsorption on Charcoal Derived from Walnut Shell

In this study a commercial charcoal derived walnut shell was used for the adsorption of ions by U.V-Visible absorption spectroscopy technique. Various operating parameters studied were adsorbent dosage, pH, contact time and temperature The effect of contact time was investigated and found that the adsorption process of Fe+3, Cr+3 ions on charcoal derived from walnut shell surface was reached at completed equilibrium within 60 min while the adsorption of Cd+2 was reached equilibrium within 30 min .The effect of the weight of the charcoal derived on the adsorption process was studied a group weight in the range (0.05- 0.2 g).The extent of the adsorption found to decreased the temperature increased i.e, exothermic adsorption .The thermodynamic parameters ΔG, ΔH, ΔS were calculated and explained in the mean of the chemical structure of the adsorbate which the values of removal percentage% and Distribution ratio (Kd).The Freundlich and Langmuir isotherm equations were applied to the data and values of parameter of these isotherms equations were evaluated the adsorption.