HIGHLY EFFICIENT COOPERATIVE MEMBRANE-TRANSPORT OF LEAD(II) IONS BY AZA-18-CROWN-6 AND PALMITIC ACID

A chloroform membrane system containing a given mixture of aza-18-crow n-6 and palmitic acid was applied for the uphill transport of Pb2+ ion s. In the presence of P2O74- ion as a suitable metal ion acceptor in t he receiving phase, the amount of lead ion transported across the liqu id membrane after 100 minutes is 89.1 +/- 1.3%. The selectivity and ef ficiency of lead transport from aqueous solutions containing other cat ions such as Zn2+, Cu2+, Ni2+, Co2+, Fe2+, Pd2+, and Ag+ ions were inv estigated. In the presence of S2O32- ion as a proper masking agent in the source phase, the interfering effects of Cu2+ ion were diminished drastically.