Soil contamination is a major threat to land use and constitutes a priority under the 6th EU Environmental Action Program (6th EAP). Farmlands near urban and industrialized areas are particularly in danger of contamination by PCBs (polychlorinated biphenyls), which have been used worldwide between the 1930s and the 1980s as pesticide extenders, sealants, industrial oils, paints adhesives, plastics and flame retardants. PCBs are extremely toxic. Their use has been severely restricted in the EU since 1985 but due to their high persistency they are still widespread in the environment, posing serious health risks due to bioaccumulation. Soils constitute a sink for PCB: the only way to improve the quality of contaminated soil is by actively remediating it.
Iron nanoparticles can be used to degrade PCB molecules (in a chemical reaction called reductive dehalogenation). However, transport of iron nanoparticles is difficult in the subsurface due to agglomeration of nanoparticles, and this strongly limits the application of iron nanoparticles for soil remediation.
The NanoDC project combines nanotechnology and electrokinetics to create a new, in-situ remediation process to recover PCB contaminated sites in which the transport of iron nanoparticles in the subsurface is enhanced by electrokinetic processes.
In this way iron nanoparticles can reach inaccessible contaminated spots in the subsurface, even in low permeability soils, allowing in situ degradation of pollutants without the need for further treatments.
The NanoDC project comprises the following stages:
(1) Experimental studies on the transport of nanoparticles in soil under the influence of electric fields.
(2) Experimental studies on the kinetics of PCBs degradation by nanoparticles.
(3) Development of a numerical model which calculates concentration of pollutants and nanoparticles.