Areas polluted with heavy metals pose a great threat to the environment. The Old Zinc-works in Celje is the most prominent case of such environmental degradation in Slovenia. Different industrial activities have left behind 17 hectares wide area, where soil contains increased concentrations of zinc, cadmium, lead and other heavy metals. In-situ immobilization of heavy metals is appropriate approach for remediation of such old burdens in terms of long term stability, environmental acceptance and economic point of view. In the world a solidification/stabilization method is the most popular method for the immobilization of heavy metals. The later consists of mixing the conventional amendments (bentonite clays, zeolites, fly ashes, cements, lime) with soil for the purpose of limiting the mobility of heavy metals. The newly developed method of solidification/stabilization has improved efficiency of soil remediation due to the use of optimal combination of iron nanoparticles with conventional amendments and geotechnical procedures for in-situ treatment of soil. Used iron nanoparticles are in a form of maghemite or zero-valent iron (nZVI). The nanosized particles can be effectively dispersed in soil, while their large specific surface area corresponds to their enhanced reactivity. The structure of nZVI is represented by Fe0 core, which is ensuring reducing power and iron oxide shell that fosters free sorption sites. The immobilization process of heavy metals in soil with nZVI is governed by redox reactions, precipitation reactions, and adsorption of heavy metals. Iron oxide nanoparticles employ similar surface processes of chemisorption that immobilize heavy metals. In the case study of remediation of the contaminated soil from Old Zinc-works the conventional amendments clays, fly ashes, zeolites are in combination with iron nanoparticles mixed with the soil. Then the mixture is with appropriate geotechnical procedures built-in in-situ to minimize the environmental impact and to achieve complete immobilization of heavy metals.
COBISS.SI-ID: 2070375