Development of Kinetic and Equilibrium Models for Removal of Cd~(2+) and Zn~(2+) Ions from Aqueous Solutions by Clinoptilolite

摘要

The ability of clinoptilolite to remove Cd~(2+) and Zn~(2+) from aqueous solution was studied. In this regard, the effects of important parameters such as initial concentration, initial pH, chemical conditioning, environmental temperature, and contact time on the Zn~2 and Cd~(2+) sorption were investigated. The results showed that the Zn~(2+) and Cd~(2+) sorption behavior was highly dependent on the pH. Sorption data were interpreted in terms of Langmuir and Freundlich equations. As a result, sorption isotherms of Zn~(2+) and Cd~(2+) ions could be best modeled by the Langmuir equation. The maximum capacity of Zn~(2+) and Cd~(2+) using modified clinoptilolite was found to be 229 and 7230 mg/g. Furthermore, kinetic investigations showed that the adsorption rate was best described by a pseudo-second-order kinetic model. With respect to the results, clinoptilolite has a particularly high potential for Cd~(2+) and Zn~(2+) removal.