Einfluß des Komplexbildungsgrades auf die Migrationsgeschwindigkeit von Eisen(II, III)‐Verbindungen

Abstract

AbstractThis paper describes relations between the degree of complexation calculated with a mathematical model (FISCHER and REISSIG, 1984) and the ion‐exchange and migration behaviour of iron(II, III)‐compounds in a simulated aquifer. In general, the bonding of the complexes to the soil matrix becomes stronger with increasing positive charge. Negatively charged or neutral complex compounds do not show any, or show only slight interactions with the soil matrix. By complexation it is possible to achieve great differences in the migration behaviour of a particular metal. In the course of migration in the deposit there was found a separation of the complex mixture in accordance with charge. The break‐through curves are characterized by a stepped shape, for this case. If weak acids or weak bases act as complex‐forming ligands, the pH‐dependent dissociation of the complexing species has to be taken into account in the complex calculation; this is represented by the example of the iron(III)‐citrate system in this paper. Moreover, experimental results concerning the migration behaviour of iron(II, III)‐fulvic acid complexes are given