Potentiometric studies on ternary complexes of some heavy metal ions containing N-(2-acetamido)-iminodiacetic and amino acids

Abstract

Solution equilibria of the ternary systems UO2(II), La(III), Ce(III)-N-(2-acetamido)-iminodiacetic acid and dicarboxylic amino acids are studied potentiometrically. The formation of 1∶1∶1 mixed ligand complexes are inferred from the potentiometric titration curves. The formation constants of the different binary and ternary complexes in such system are evaluated at t=24±0.1°C and μ=0.1 mol dm−3 (KNO3). It is deduced that the ternary complex is more stable than the corresponding binary amino acid anion complex. Moreover, the order of stability of the binary or ternary complexes in termes of nature of amino acid and metal ion is investigated and discussed.