Kinetics and Thermodynamics Studies of Cobalt (II) Adsorption onto Alumina

Adsorption for alumina-cobalt (II) ions solution system was investigated as a function of adsorbent dose, contact time, temperature, pH of solution and initial concentration of adsorbate. The optimum conditions for removal of cobalt (II) ions were found as pH 7.5-8.5, adsorbent dose of solution 20 gl(-1), equilibrium time 90 minutes and initial concentration range 5-50 mgl(-1). Pseudo-second-order kinetics was observed for adsorption of cobalt while cobalt removal process does not seem to control the intra-particle diffusion. Langmuir, Freundlich and Dubnin-Radushkevich isotherm models were applied to analyze the equilibrium isotherms for adsorption of cobalt (II) ions onto alumina. The experimental results indicated that equilibrium data follows the Langmuir model within used concentration range.