Selective lead(II) transport in a liquid membrane system with octylsulfanylacetic acid ionophore

The properties of octylsulfanylacetic acid in pertraction of cations, especially lead(II), were investigated. Basic physico-chemical characteristics of the carrier, i.e., the dissociation constant Ka and surface tension σ of its solution in 1,2-dichloroethane, were determined. A multimembrane hybrid system composed of a liquid membrane and two polymer cation-exchange membranes (Nafion-117) was used as the transport cell. The following order of selectivity was observed: Pb(II) ≫ Ca(II) ≈ K(I), with the separation factors αCaPb and αKPb in the range of 4–45 and 6–47, respectively. The maximum output fluxes of lead(II) varied from 1.7 to 6.87 · 10− 12 mol cm2 s− 1 depending on the carrier concentration (0.05–0.1 mol dm− 3) in a liquid membrane.