Subsurface transport of engineered nanoparticles

Nanomaterials possess unique physical, electrical and chemical properties which make them attractive for use in a wide range of applications. Given the increased production and utilization of nanomaterials, there is heightened potential for their release into the environment where subsequent impacts on ecosystems are of significant concern.

Contact: Fritjof Fagerlund

Understanding the subsurface transport of these nanoparticles is a key step in determining the overall level of interaction of nanoparticles with their surroundings. Due to the relatively small sizes of nanoparticles, they are much more sensitive to physical and chemical heterogeneities present in the subsurface. The presence of a gaseous phase creates further heterogeneity and complications for the flow and transport behavior of nanoparticles in subsurface systems. Additionally, the understanding of nanoparticle transport processes is a key for other engineering applications such as destruction of contaminants and delivery of pesticides to plants. The retention and mobilization mechanisms of different types of engineered nanomaterials are of particular importance both for the potential risks associated with these materials and their successful utilization in engineering applications. The following illustrations show: an example of nanoparticles (Figure 1) the different possible locations of nanoparticle deposition in a partially saturated system (Figure 2), and destruction of contamination in the groundwater using zero-valent iron nanoparticles (Figure 3).

Nanoparticles. Photo.

Figure 1. Nanoparticles.

Model of deposition locations of nanoparticles. Illustration.

Figure 2. Possible deposition locations of nanoparticles in unsaturated porous media.

Oxidized iron particle. Photo.

Figure 3. Experimental study of treatment of percholoroethylene (PCE) contamination (red color) in a dense non-aqueous phase liquid (DNAPL) source zone using nanoscale zero-valent iron (NZVI) particles (black color). Acting as a electron donor, the NZVI degrades the PCE to harmless endproducts (ethene, ethane, acetylene). Oxidized particles (yellow color - rust) are transported away from the treatment zone with the flowing groundwater.