Tuesday, November 3, 2009
Convention Center, Exhibit Hall BC, Second Floor
In the environment, nanoparticles (diameter = 1 – 100 nm) and colloids are present naturally as the smallest fraction of particulate matter in the soil. These particles act as dispersed particulate matter in aqueous systems such as surface- and ground- water. This study will investigate the importance of nano-sized particles as nutrient/contaminant carriers, focusing on the essential plant nutrient phosphorus (P), through soil-water environment. These small particles will behave differently than larger clay particles, which are a few microns in diameter, due to their extremely high surface area to volume ratio. This may have an effect on the ability and rate of P adsorption and desorption from the colloidal surfaces. Additionally, the small size of these particles may provide for easier transport through complex surface- and subsurface-matrices. The objective of this study is to determine the reactivity of environmental nanoparticles in P-rich agricultural surface soils in South Carolina, as well as the role of these nanoparticles in nutrient/contaminant transport. Agricultural surface soils are often treated with animal based or synthetic fertilizers high in P. Transport of P into surface- and ground-water has adverse effects on water quality. This transport is relatively well understood at the scale of larger clay particles, however, the transport of P with environmental nanoparticles has not been well studied. To understand the reactivity of P in environmental nanoparticles, we will use bench-scale desorption studies, coupled with a series of colloidal separations. Colloids will be characterized using chemical digestion and electron microscopy, both SEM and TEM. External structure of these particles, as well as chemical make-up will be analyzed.