Facilitated transport of cobalt through bulk liquid membranes containing diethylhexyl phosphoric acid Original Research Article

The transport of cobalt (II) ions through bulk liquid membrane containing di(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene as mobile carrier and protons as counterions in the product phase (H2SO4 was studied. The transport kinetics was analysed by means of a kinetic model involving two consecutive irreversible first order reactions. The rate constants of the extraction and stripping reactions were experimentally determined. Model curves of tune dependence of Co (II) reduced concentrations in the feed, membrane and product phases show good agreement with the experimental data. The influence of the carrier concentration in the membrane phase and the counterion concentration in the product phase was analysed. The increase of both led to an increase in the recovery of cobalt (II), the optimal conditions in the range studied being 6% v/v of D2EHPA in the membrane phase and 1 M sulphuric acid in the product phase.