Selective transport of zinc as Zn(SCN)42− ion through a supported liquid membrane using K+-dicyclohexyl-18-crown-6 as carrier

A new supported liquid membrane (SLM) system for the selective transport of zinc ion is described. The SLM used is a thin porous polyvinyldifluride membrane impregnated with dicyclohexyl-18-crown-6 dissolved in nitrophenyloctyl ether. Potassium-dicyclohexyl-18-crown-6 acts as a highly efficient carrier for the uphill transport of zinc as Zn(SCN)42− through the SLM. In the presence of l-Cysteine as a metal ion acceptor in the strip solution, transport of zinc occurs almost quantitatively after 5 h. The selectivity and efficiency of zinc transport from aqueous solution containing different mixtures of Co2+, Ni2+, Cu2+, Pb2+, Cd2+, Hg2+, Fe3+ and Cr3+ ions were investigated. In the presence of citrate ion and thiourea as suitable masking agents in the feed solution, the interfering effects of Pb2+ and Cu2+ ions were completely eliminated