DISTRIBUTION COEFFICIENT OF A METAL IN THE PRESENCE OF A CHELATING AGENT

Abstract

A linear adsorption model has been developed to investigate the effect of chelating agents on the adsorption of metal ions by introducing an extended concept of the distribution coefficient. In addition, batch adsorption experiments were performed on the cobalt/EDTA/bentonite adsorption system in order to analyze the effect of chelating agent and to validate the developed adsorption model. The experimental results showed a linear adsorption isotherm, thus validating the assumption of a constant distribution coefficient. Also, the concentrations of all species participating in the adsorption/chelation reaction could be determined by the developed model. The results of this study showed that adsorption of a metal solute was greatly affected by the presence of chelating agents, even in a small amount, by increasing the total solubility of the metal and reducing the distribution coefficient up to more than two orders of magnitude.