A Kinetic Study of Copper Ion Extraction by Kelex 100 at a Heptane–Water Interface

Abstract

A study of the kinetics of Cu2+extraction by 7-(4-ethyl-1-methyloctyl)8-hydroxyquinoline (Kelex 100) has been undertaken in a static transfer cell, where the total concentration of the Cu2+–Kelex 100 complex in the organic phase is monitored in situ as the reaction proceeds using attenuated total internal reflectance spectroscopy. The temporal characteristics of the extraction of Cu2+from water into heptane could be accounted for using a simple one-dimensional diffusion model coupled with a reaction-limited interaction between Cu2+and Kelex 100. Rate constants for the reaction of Kelex 100 and Cu2+at a model interface were obtained from stopped flow experiments using a neutral micelle (C12E8) system. These rate constants were used to model the reaction between Cu2+and Kelex 100 at the heptane–water interface.