Kinetics and thermodynamics of adsorption for Cd on green manufactured nano-particles

Magnetic nano-particles CuFe2O4 were successful manufactured from industrial sludge by combination of acid leaching, chemical exchange, and ferrite process. For the first time these recycled nano-particles were used as adsorbent to investigate the kinetics and thermodynamics for adsorption of Cd in aqueous solutions. These experimental results showed that Cd2+ adsorption efficiency increased from 0.85 to 99.9% when pH increased from 2 to 6. The maximum adsorption capacity of Cd2+ was found to be 17.54 mg g(-1) under the conditions at pH 6.0, contact time 30 min, and temperature 318K. The pseudosecond-order kinetic model provides the best correlation with the experimental data compared to the pseudo-first-order model. The Langmuir model yields a better fitting than the Freundlich model for Cd2+ adsorption on CuFe2O4 nano-particles under investigated temperatures. The thermodynamic constants of the adsorption process were evaluated, Delta G degrees, Delta H degrees and Delta S degrees is -6.05 kJ mol(-1) (at 318K). 0.71 kJ mol(-1). and 4.53 J mol(-1) K-1, respectively. These results imply that Cd2+ adsorption onto CuFe2O4 is feasible. spontaneous and endothermic in nature. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.