Kinetic study of the effect of carrier and stripping agent concentrations on the facilitated transport of cobalt through bulk liquid membranes

Heavy metal contamination of industrial effluents and waste waters is a very important environmental problem. Heavy metals tend to accumulate in living organisms causing various diseases and disorders. So the search for extraction techniques to remove those heavy metals are of increasing interest. Liquid membranes have shown great potential in this way, especially in cases where solute concentrations are relatively low and other techniques cannot be applied efficiently. A kinetic study of the effect of carrier and counter ion concentrations on the transport of cobalt(II) through bulk liquid membrane containing di-2-ethylhexyl phosphoric acid (D2EHPA), as mobile carrier, in kerosene and protons (H2SO4), as counter ions, in the product phase is carried out is this paper. The transport kinetic 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 determined for all experimental conditions studied. Maximum transport fluxes of cobalt(II) through the bulk liquid membrane were also calculated.