FORMATION-CONSTANTS OF TERNARY COMPLEXES OF SOME HEAVY-METAL IONS WITH N-(2-ACETAMIDO)IMINODIACETIC ACID AND ALIPHATIC OR AROMATIC-ACIDS

Solution equilibria of the ternary systems involving La(III), Y(III), Ce(III) and UO2(II), N-(2-acetamido)iminodiacetic acid H2NCOCH2N(CH2CO2H)(2) and some aliphatic of aromatic acids have been investigated potentiometrically. The formation of 1 : 1 : 1 mixed ligand complexes is inferred from the potentiometric titration curves, Formation constants of the different binary and ternary complexes formed in such system were determined at 25 +/- 0.1 degrees C and mu = 0.1 Mdm(-3) (KNO3). It is deduced that the mixed ligand complexes are more stable than the corresponding binary ones containing the aliphatic or aromatic acidate moiety. The order of stability of the binary and ternary complexes is investigated and discussed in terms of the nature of both the metal ion and the secondary ligand (aliphatic or aromatic acid).