Separation of a given species from a complex mixture of other species is of special importance in industrial and analytical chemistry and separation sciences. Often, various interfering compounds must be removed and/or the compounds of interest must be enriched before detection is possible. Liquid membranes(organic liquids contact with two separated aqueousphases) are well known as one of the most powerful tools for such separation and enrichment purposes [1–3]. Recently, we have reported a highly selective membrane transport of silver(I) by 5, 12-Di(phenoxymethyl)-1,4-dioxa-7,10-dithiacyclododecane-2,3-dione as carrier [4]. In this investigation we employed this synthesized crown ether as an excellent specific ion carrier for the highly efficient and selective transport of Ag+ ions through a bulk dichloromethane membrane. The effect of parameters influencing the transport efficiency such as the pH of the source and receive phase, type and concentration of stripping agent in the receive phase, the concentration of ionophore and the organic diluent used in the membrane, type and concentration of the fatty acid used as surfactant in the organic phase and time has been investigated and discussed. A bulk liquid membrane at optimum experimental conditions consisted of 2.5×10−3 M ionophore and 5×10−3 M palmetice acid as surfactant in dichloromethane that placed between an aqueous source phase containing 5×10−4 M silver cation at pH 5 and an aqueous receiving phase with 5×10−3 M thiosulfate as stripping agent at pH 4 results in an efficient transport of copper from the source phase to the receiving phase. The amount of copper transport through the liquid membrane after 5 hours was 80.86± 1%.

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