Complexation of cations Pb(II), Cd(II) and Hg(II) by a new copolymer based on Acrylic and Crotonic acids in aqueous media

The complexes formation of divalent metal ions M(II) {M= Pb, Cd and Hg} with a new copolymer based on acrylic and crotonic acids was investigated in aqueous media with NaNO₃ (0.1 M) as supporting electrolyte. pH titrations of coplymer alone and in presence of metal were realized through the batch method to determine the properties of acid base and complexe–forming of ligand copolymer. The results show that for Pb(II), the predominant complex specie is PbA₂ with a stability constant pK₂ = −8.82. On the contrary, with cadmium and mercury neither MA nor MA₂ becomes predominant and the stability increases as follows: Pb(II)> Cd(II)> Hg(II). The synthesized copolymer is a good fixation agent that can be used in the recovery of heavy metals, known for their high toxicity in hydric media.