Selective transport of mercury as HgCl42− through a bulk liquid membrane using K+-dicyclohexyl-18-crown-6 as carrier

Potassium-dicyclohexyl-18-crown-6 cation complex was used as an excellent carrier for the selective and efficient transport of mercury as HgCl42− complex anion through a chloroform bulk liquid membrane. In the presence of thiocyanate ions as a suitable stripping agent in the receiving phase at optimum experimental conditions, the amount of mercury transported across the liquid membrane after 2 h was 95.4±1.5%. The selectivity of mercury transport from aqueous solutions containing other cations, such as Li+, Tl+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Fe3+ and Cr3+, was investigated. With the exception of Mg2+ and Ca2+ with some potential interference, in all other cases, the interfering effect of the cations was found to be negligible; most of the cations did not interfere with the mercury transport even at a Mn+/Hg2+ molar ratio of ≥100.