STUDY ON SEPARATION OF HEAVY-METAL IONS IN A NEUTRAL MACROCYCLE-MEDIATED EMULSION LIQUID MEMBRANE SYSTEM

The preferential transport phenomena of neutral cation-anion moieties in neutral macrocycle-facilitated emulsion liquid membrane were described in this study. Emulsion membrane systems consisting of (1) aqueous source phase containing 0.001 M M(NO3)2 (M = Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Sr2+, Cd2+, and Pb2+) (2) a toluene membrane containing 0.01 M ligand (DBN3O2, DA18C6, DT18C6, TT18C6, HT18C6) and the surfactant span 80 (sorbitan monooleate) (3% v/v) and (3) an aqueous receiving phase containing Na2S2O3 or NaNO3 were studied with respect to the disappearence of transition metal ions from the source phase as a function of time. Cation transports for various two component or three component equimolar mixture of transition metal and Cu2+ in a emulsion membrane system incorporating macrocyclic ligand (HT18C6) as carrier were determined. Cu2+ was transported higher rates than the other M2+ in the mixture solution. Equilibrium constants for cation-source phase co-anion, cation macrocycle and cation-receiving phase reagent interaction are examined as parameters for the prediction of cation transport selectivities.