Ni2+ Removal From Aqueous Solutions Using Conditioned Clinoptilolites: Kinetic and Isotherm Studies

Abstract

The aim of this study is to investigate the effects of conditioning with NaCl and HCl solutions on removal of Ni ions from aqueous solutions using natural clinoptilolite. Batch studies were performed to evaluate the effects of various parameters such as chemically conditioning, adsorbent amount, contact time, initial pH of the solution, mixing temperature, and initial metal ions. The results clearly showed that the conditioning improved both the exchange capacity and the removal efficiency. Langmuir, Freundlich, Temkin, and Duhinin-Kaganer-Radushkevich (DKR) isotherm models were adopted to describe the adsorption isotherms. Adsorftiion isotherms of Nt'+ ions could be best modeled by Langmuir equation. Three simplified models including pseudo-second-order, intraparticle diffusion and EIovich were used to test the adsorption kinetics, These results indicate a significant potential for the natural and conditioned clinoptilolites as an adsorbent/ionexchange material for heavy metal removal. © 2008 American Institute of Chemical Engineers.