Sorption characteristics of heavy metal ions by a natural zeolite

Abstract

Abstract Zeolites have been shown to be effective adsorbents for the removal of heavy metals from aqueous solutions. A natural material from Cuba, containing zeolite, has been used for the removal of several metal ions, namely Cu 2+ , Zn 2+ , and Ni 2+ , to evaluate its potential use as a low‐cost adsorbent. Batch experiments have been conducted to evaluate the process kinetics and the removal equilibrium at different pH values, metal and zeolite concentrations. Pseudo‐second order kinetics and Freundlich equilibrium parameters have been obtained. Results suggested that this natural zeolite has a high potential for heavy metal retention. The selectivity of the studied metals was determined as Cu 2+ ≫ Zn 2+ > Ni 2+ , related to the first hydrolysis equilibrium constant. The metal removal efficacy was strongly dependent on pH, and to a lesser extent on metal/zeolite ratio. Copyright © 2005 Society of Chemical Industry