HIGHLY SELECTIVE TRANSPORT OF LEAD CATION THROUGH BULK LIQUID MEMBRANE BY MACROCYCLIC LIGAND OF DECYL-18-CROWN-6 AS CARRIER

摘要

The liquid membrane transport of Pb~(2+) cation using decyl-18-crown-6 as selective ion carrier was studied. The transport of lead ion across the liquid membrane in the presence of S2O_3~(2-), P2O_7~(4-), CN~-, SCN~- and DDC~- as stripping agents in the receiving phase shows that the nature and the concentration of the stripping agents affect on Pb~(2+) cation transport and the maximum transport occurs when the sodium thiosulfate (Na2S2O3) was used. The effects of various parameters influencing the transport efficiency such as the pH of the source and receiving phases, the concentration of picrate ion as counter ion in the source phase were also studied. Five replicated experiments show that a value 82.12 ± 2.09% of the initial concentration of the Pb~(2+) cation in the source phase is extracted into the receiving phase after 4 hours. Also the selectivity and efficiency of lead ion transport from the source phase containing equimolar mixtures of Na~+, K~+, Ca~(2+), Ni~(2+), Cu~(2+), Cd~(2+) and Ag~+ metal cations were investigated.