TRANSPORT OF TC(VII) AND RE(VII) THROUGH A SUPPORTED LIQUID MEMBRANE

Tc(VII) and Re(VII) were transported from feed solutions, having a pH range between 0 and 1.36, to distilled water and 0.5 mol dm(-3) NaHCO3 solutions by means of a TBP-decalin membrane supported on a microporo us polytetrafluoroethylene sheet. The NaHCO3 solution was shown to be better than distilled water as a strip solution giving higher rates of transport. Only a slight difference in the initial transport rates of Tc(VII) was observed for the feed solutions at the pH range from 0 to 1.36. However, the transport of Tc(VII) from the feed solution at pH 0 showed signs of saturation soon after the start of permeation. There fore, a feed solution at around pH 1 is concluded to be suitable for t he transport of Tc(VII). The transport behavior of Re(VII) is similar to that of Tc(VII), but the transport rate of Re(VII) is smaller than that of Tc(VII) in the pH region studied. Permeability coefficients ar e determined to be 11 x 10(-4) and 8 x 10(-4) cm/s for Tc(VII) and Re( VII) transport from the feed solution at pH 0.74 to a NaHCO3 strip sol ution, respectively.