Removal of Cd (II) ion from waste water by adsorption onto polyaniline coated on sawdust

The ability of Polyaniline coated on saw dust as synthetic adsorbent was investigated for adsorptive removal of Cd (II) ions from aqueous solutions by batch operation. It was found that polyaniline coated on saw dust (PANI/SD) is very easy and simple to prepare and can be used as an effective adsorbent for removal of Cd (II) ions from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied. The adsorption of Cd (II) ions increased with an increase in pH. The optimum solution pH for adsorption of Cd (II) from aqueous solutions was found to be 6. Adsorption was rapid and occurred within 20 min for a cadmium concentration range of 10:40 mg L-1. The kinetic process of Cd (II) adsorption onto PANI/SD was found to fit the pseudo-second-order rate equation. The equilibrium adsorption data for Cd (II) were better fitted to the Freundlich adsorption isotherm model. (C) 2011 Elsevier B.V. All rights reserved.