Kinetics and equilibrium studies of heavy metal ions removal by use of natural zeolite

Abstract

In this study, the removal of heavy metal ions from aqueous solution using; natural clinoptilolite, obtained from the Biga-Canakkale region of Turkey, under different experimental conditions was investigated. The efficiency of zeolite as an adsorbent for the removal of heavy metals such as Cd (11), Cu (11), Ni (11) from aqueous solutions has been determined at the different initial concentration, zeolite amount, agitation speed and pH. Adsorption data have been interpreted in terms of Langmuir and Freundlich equations. The results were provided strong support for the adsorption of heavy metals into clinoptilolite and which were found to fit sufficient by the Langmuir isotherm in the most of case. The selectivity of the studied metals was determined as Cd (11)>Ni (11)>Cu (11). The sorption kinetics was tested for the first order reaction, intra-particle diffusion, pseudo-first order, and pseudo-second order reaction at different experimental conditions. The rate constants of sorption for all these kinetic models were calculated. Good correlation coefficients were obtained for the pseudo-second order kinetic model showing that cadmium, copper and nickel metal ions uptake processes followed the pseudo-second order rate expression.