A supported liquid membrane system for simultaneous separation of silver(I) and mercury(II) from dilute feed solutions

An innovative application of supported liquid membranes (SLMs) to the selective simultaneous separation of Ag+ and Hg2+ ions from a dilute feed by employing a two-membrane–three-compartment cell is introduced. Two micro-porous PP supported membrane loaded with a mixed N/O/S-donor macrocycle aza-thioether crown containing the 1,10-phenanthroline sub-unit (PhenS2O) and tetrathia-12-crown-4 (TT12C4) were used for selective transport of silver and mercury ions, respectively. The PhenS2O-loaded membrane was placed between the first and the second compartments, whereas the TT12C4-loaded membrane was placed between the second and the third compartments of the transport cell. The use of this cell assembly, under optimized experimental conditions, made it possible to transport Ag+ and Hg2+ ions simultaneously from a 1.0 × 10−3 M picric acid feed solution containing these two species and several other interfering ions into the two corresponding strip compartments of the transport cell. Sodium thiosulfate (0.04 M) and EDTA disodium salt (0.025 M) were used as stripping agents for Ag+ and Hg2+ ions, respectively.