Abstract

Adsorption behavior of Cadmium ions, in aqueous solution, at raw powder and activated carbon derived from Parthenium hysterophorussp weed plants, have been studied. The adsorbent materials were characterized using XRD and FTIR techniques. Effects of adsorbent dose, Cd(II) ions concentration, pH and adsorbate-adsorbent contact time for the removal of Cd(II) ions from aqueous solution have been investigated. The observed adsorption data was analyzed in the light of Langmuir and Freundlich adsorption isotherm models. The adsorption data better followed the pseudo second order kinetic model than the pseudo-first order model. It was found that the removal of Cd(II) ions by the adsorbents may concurrently involve both surface adsorption as well as intra-particle diffusion. Though the adsorption of Cd(II) ions at the studied adsorbents is endothermic, yet it becomes feasible due to the predominate entropy gain. With Cd(II) ions initial concentration 50mgL-1, their maximum percent removal by raw plant powder and the derivedactivated carbon, were 97% and 99.5%, respectively and their adsorption capacities for the Cd(II) ions, predicted byLangmuirmodel, were: 7.4 and 45.1mg g-1,respectively.

Keywords: Adsorption;Isotherm; Activated carbon; Parthenium hysterophorussp