Kinetics and equilibrium studies of heavy metal ions removalby use of natural zeolite

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