title: The acidobasic and complexation properties of humic acids Study of complexation of Czech humic acids with metal ions.
abstract: The acid-base and complexation properties of humic acids (HAs) extracted from bohemian brown coals were studied. The acid-base behavior corresponds with the model of HA as a mixture of mono- and diprotic acids. This model was also verified on commercial HA substances (Aldrich and Fluka). HA binds strongly with heavy metal ions and the highest stability constant of HA-metal ion complexes was observed for copper(II). Stability constant values were found to decrease in the order: Cu(2+)>Ba(2+)>Pb(2+)>Cd(2+)>Ca(2+). Both acidobasic models for HA alone and those for HA-metal ion interactions were proposed and the computational methodology for polyelectrolyte equilibria studies demonstrated.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlárská 2, 611 37 Brno, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Lubal
authors.forename: D
authors.initials: D
authors.lastname: Siroký
authors.forename: D
authors.initials: D
authors.lastname: Fetsch
authors.forename: J
authors.initials: J
authors.lastname: Havel