Study of the Faradaic transfer of ions in a 1,2-dichloroethane extraction system. Similarities and differences in character between cobalt(II) and nickel(II) with 1,10-phenanthroline as the complexing agent

Abstract

The character of the Faradaic transfer of Co²⁺ and Ni²⁺ ions across a dichloroethane (DCE)/aqueous interface in the presence of 1,10-phenanthroline (phen) as the complexing agent was observed by current scan polarography at an electrolyte dropping electrode (EDE) and by chronopotentiometry at a stationary water electrode (SWE). The observed behaviour was similar for both, when the complexing agent was originally added to the aqueous phase; however, very different behaviour was observed when the complexing agent was originally added to the organic phase (DCE). Thus, it follows from the difference in the behaviour, resulting from their different kinetic rates of association with phen, that Co²⁺ and Ni²⁺ can be easily separated from each other by ‘extraction’ using an electric field.