Tetraaza-14-crown-4 has been used as a highly selective and efficient carrier for the uphill transport of Pb2+ ion through a chloroform bulk liquid membrane. By using pyrophosphate as a metal ion acceptor in the receiving phase, the amount of Pb2+ transported across the liquid membrane after 90 min is found to be 95 ± 2.6 %. The selectivity and efficiency of lead ion transported from aqueous solution containing equimolar mixtures of Cu2+, Hg2+, Ca2+, Mg2+, K+, Na+, Ni2+, Zn2+, Fe3+, Ag+ and Cd2+are also investigated. The proposed system reveals not only an improved selectivity for Pb2+ ion transport, but also a much lower transport time
