BIOSORPTION OF CADMIUM FROM AQUEOUS SOLUTONS USING ORANGE PEEL, WALNUT AND HAZELNUT SHELL

Biosorption of Cd(II) ions from aqueous solutions has been studied and determined to adsorption capacity. The experimental data obtained from batch equilibrium tests have been analyzed by three two-parameter (Freundlich, Langmuir and Temkin) isotherm models, four three-parameter (Redlich-Peterson, Sips, Toth and Khan) isotherm models and kinetic models including the pseudo-first order and pseudo-second order. The adsorption data fit well with Temkin isotherm for orange peel and Freundlich isotherm for walnut and hazelnut shell. Maximum experimental adsorption capacity was found to be 13.947, 8.57 and 8.847 mg/g for orange peel, walnut shell and hazelnut shell, respectively. Experimental kinetics data was well-fitted for pseudo-second order for all adsorbents and correlation coefficient for kinetics was above 90%.