Low cost natural adsorbent for removal of Pb(II) ions from waste solutions

Document Type : Original Article

Authors

Atomic Energy Authority, Hot Labs. Centre

Abstract

In this paper, the adsorption behavior of Pb2+ ions from aqueous solution onto castor stem as a natural adsorbent was investigated under various experimental conditions. Characterization of castor sorbent was evaluated by SEM, XRD, FTIR, DT and TGA, BET surface area analysis, and CHNS elemental analyses. Operational parameters such as pH, contact time, initial ion concentration, sorbent dose, particle size, competing ions, and temperature were also studied. Adsorption data fitted well with the Langmuir and Freundlich models. However, Freundlich isotherm displayed a better fitting model than Langmuir isotherm because of the higher correlation coefficient that the former exhibited, thus, indicating to the applicability of multilayer coverage of the Pb (II) on the surface of adsorbent. On the basis of distribution studies, the distribution coefficient (Kd) increases with increasing the reaction temperatures of the solution. Thermodynamic parameters, ∆Ho, ∆Go, and ∆So were calculated and indicated an endothermic and spontaneous process. Castor is a good adsorbent for the removal of Pb(II) from heavy metals wastewater and confirmed the validity of the proposed method for real samples.

Keywords