Conductimetric behaviour of humic acids with Cu(II) ions

Humic substances play an important role in the behaviour of Cu(II) in natural environments, due to the formation of complexes which can modify the mobility of these ion. A study of the interaction between Cu(II) ions and a lignite humic acids in different metal - ligand ratios has been made by conductimetric techniques. The results are interpreted using an excess function which relates the conductivity of the mixture and of the separated components. Its variation with concentration and with pH in absence of heavy metal cations is discussed. The capacity of complexation of the lignite humic acids enables them to be used in environmental sites polluted by heavy metals such as copper.