(17a) Reactivity, Fate and Transport of Metal Oxide Nano-Particles in Aquatic System

The use of nano-technology and the application of products containing nano-scle particles have been increasing. It is likely that with increased production of nanomaterials that there will be a net flux into the environment. Assessment of the potential risk of these releases and the extent of required restoration efforts will require understanding of the reactivity and mobility of nanomaterials in the environmental setting. Although, lab synthesized nanoparticles, for which the characteristics are easy to control, are the main source for most current studies on nanoparticles implications, the transport and fate of commercial available nanoparticles has greater practical importance. Electrophorosis studies showed that isoelectric points of these nano-particles vary over a wide range and impurities contained in these commercial nano-particles. Inductively coupled plasma emission spectroscopy (ICP) was employed to trace the impurities in the commercial nanoparticles, which might impact the point of zero charge of the particles. Sorption phenomena significantly affected the transport, retention and ultimately fate of nano particles in soils and subsurface systems. Particles transport through the column was experimentally measured and mathematically modeled. Electrolyte concentration and the presence of natural organic matter have significant influence on zeta potential, and transport of the particles has been studied. The results were correlated with the stability of nanoparticle in suspension the experimental data on their transport through sand-packed columns. Theoretical relationships are derived to link experimentally measured zeta-potential quantities of nanoparticles with classical DLVO theory.