Das Projekt "Laboratory Experiments for the Development of Improved Methods for Heavy Metal Immobilization: A Contribution to the Gentle Remediation of Soils Polluted by Heavy Metals" wird/wurde gefördert durch: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Es wird/wurde ausgeführt durch: Eidgenössische Technische Hochschule Zürich (ETH), Institut für Terrestrische Ökologie, Arbeitsgruppe Bodenschutz.The main purpose of this project is the development of new fixation methodes for heavy metals in the laboratory. These methods should be used then in soils to improve the immobilization capacity for easily soluble heavy metals such that they become dissolved only to a minor extent during a possible acidification process. The investigations in the laboratory include three methods: a) addition of polynuclear aluminium complexes to heavy metal solutions in order to co-precipitate the metals, b) addition of polynuclear aluminium complexes to montmorillonite (betonite) in order to form coatings on the plane surface of the clay mineral, which, compared to the bare montmorillonite, exhibit improved adsorption capacities for heavy metals, and c) synthesis of immogolite and amorphous aluminium silicates from dissolved Si polynuclear Al complexes to improve the cation exchange capacity in soils.