Separation of metal ions by ligand-accelerated transfer through liquid surfactant membranes

Abstract

The rate of extraction of heavy-metal ions is greatly accelerated by the presence of a ligand in the aqueous solution containing the metal ions. The ligand effect on interfacial mass-transfer rates has been defined by measuring the rate of extraction of cobalt by di-2-ethylhexyl phosphoric acid using sodium acetate as ligand in a modified Lewis cell. The effect of a surfactant such as polyamine on mass transfer at liquid/liquid interfaces has been investigated and is found to be quite significant. This interfacial resistance to metal extraction by surfactant-membrane processes must be taken into account when modelling such systems.