TRANSPORT OF TITANIUM DIOXIDE NANOPARTICLES IN SAND

Nanoparticle contaminants are becoming more prevalent as their use by industry increases. These emerging contaminants are defined as particles with a diameter of 1 - 100nm, and come from a variety of sources, both commercial and industrial. Concern about nanoparticles has grown as early studies have indicated that, aside from their own toxicity, nanoparticles also have the ability to increase the mobility of other contaminants in the environment. Nanoparticles enter the environment through various waste streams, including land-applied biosolids. A series of miscible-displacement experiments was performed to examine the retention and transport of titanium dioxide in natural porous media. The experiments were conducted in a manner to characterize longer-term behavior. In addition, the impacts of residence time (e.g., mean pore-water velocity) and water chemistry (e.g., pH and ionic strength) on transport were assessed.