Application of ligno-cellulosic waste material for heavy metal ions removal from aqueous solution

This paper reports the feasibility of using ligno-cellulosic agricultural waste material to remove Ni(II) and Cd(II) from model waste water. For this, Arachis hypogea shells (AHS) has been used in natural (AHSN) as well as in immobilized form of beads (AHSB). Effect of various process parameters, namely, pH, adsorbent dose, initial metal ion concentration, stirring speed and contact time has been studied in batch mode. Maximum removal efficiency was observed at pH 6.0 for Ni(II) and Cd(II). Adsorption equilibrium studies were analyzed using Freundlich, Langmuir and Temkin's isotherm models. Adsorption kinetic studies have been carried out using Pseudo 1st order equation of legergren, Pseudo second order, intraparticles diffusion and liquid films diffusion. It was found that pseudo second order kinetic model, Freundlich and Temkin's isotherm fitted well. (C) 2013 Elsevier Ltd. All rights reserved.