A kinetic study of nickel ion extraction by Kelex 100 at the liquid-liquid interface

Abstract

A study of the kinetics of nickel ion extraction by Kelex 100 (7-(4-ethyl-1-methyloctyl)8-hydroxyquinoline) is presented. A reaction scheme is proposed and the kinetics are shown to be controlled by the two parallel initial addition steps. The forward reaction rate constants are determined for these cases. The techniques used to measure the kinetics are, stopped flow where the organic ligand is solubilised in micelles and attenuated total internal reflection spectroscopy (ATR). The first is based on the kinetics at a non-ionic micelle interface and the second at a free aqueous-organic interface. Identical results for the kinetics were obtained from the two techniques when variations in the i..