Influence of carbonate and calcium ions on the phosphonate complexation with cu, zn, cd and ni in fresh waters: an evaluation of thermodynamic constants and a chemical model

摘要

The impact assessment of two phosphonate ligands: HEDP [1-hydroxyethane-1, 1'-diphosphonic acid] and ATMP [aminotris(methylenephosphonic acid)], on th speciation of various divalent cations (Cu, Zn, Cd and Ni), was undertaken taking into account both water alkalinity and hardness. In order to model the phosphonate/carbonate/calcium/metallic cation systems, a critical study of the literature concerning stability constant of soluble and insoluble species was carried out. The model systems show that speciation of metallic phosphoate complexes depends on the alkalinity and with more particularly, the hardness of water.