SOLVENT EXTRACTION OF LEAD BY TRILAURYLAMMONIUM CHLORIDE DISSOLVED IN TOLUENE FROM DIFFERENT CHLORIDE MEDIA

The extraction of Pb(II) from chloride solutions by trilaurylammonium chloride (TLAHC1) dissolved in toluene has been studied by metal distribution measurements. The work has been performed at three different aqueous chloride concentrations (1.0, 2.0 and 3.0 mol.dm^?3NaCl). The treatment of the experimental data at each chloride concentration agrees with the stoichiometry of the extracted metal species in the organic phase while the values of their equilibrium constants are different for the various chloride concentrations. The extraction process is explained by the following extraction reactions

The corresponding logarithmic values of K₂and K₅at the different chloride concentrations, I, are: K₂K₅, I; 4.62, 8,51, 1.0; 4.54, 8.38, 2.0; 4.48, 8.32, 3.0. The values obtained have been correlated by using the Specific Interaction Theory (S.I.T.) and the interaction coefficient for the Pb²⁺,Cl^?ions as well as the thermodynamic constants, Kn⁰, have been determined.