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Stability and transport of commercial metal oxide nanoparticles in aquatic systems
Citation:
Li, Z., G. A. Sorial, AND E. SAHLE-DEMESSIE. Stability and transport of commercial metal oxide nanoparticles in aquatic systems. Presented at The 238th ACS National Meeting, Washington, DC, August 16 - 20, 2009.
Impact/Purpose:
To inform the EPA
Description:
The use of nano-technology and the application of products containing nano-scale particles have been increasing. When nano-scale particles are released to the environment, their stability, transport properties and interaction with other pollutants and natural organic matter play a key role in the risk analysis. Although lab synthesized nanoparticles, for which the characteristics are easy to control, are the main source for most current studies on nanoparticle implications, the transport and fate of commercial available nanoparticles has greater practical importance. In this research, 15 types of nanoparticles were obtained from vendors and their potential risks were evaluated. The physical and chemical properties of the nanoparticles were characterized and the results differ from those reported by the vendor. Electrophorosis studies showed that isoelectric points of these nanoparticles vary over a wide range and impurities contained in these commercial nanoparticles. 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. Electrolyte concentration and the presence of natural organic matter have significant influence on zeta-potential of the particles. 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.