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Characterizing Aqueous Fullerene Suspensions
Citation:
BOUCHARD, D., X. MA, AND C. Isaacson. Characterizing Aqueous Fullerene Suspensions. Presented at National Environmental Monitoring Conference, Washington, DC, August 11 - 15, 2008.
Impact/Purpose:
The goal of this work is to develop analytical methodologies for characterizing fullerenes and fullerene derivatives in aqueous colloidal suspensions.
Description:
Over 500 products purporting to contain nanoscale materials were on the market in 2007 and projections have suggested that the market for nanomaterial-containing products could reach over $2 trillion by the year 2014. With the expected development, production, and use of nanomaterials, the need for further research on the transport and fate of nanomaterials in the environment has been recognized. Federal agencies and industry liaison groups have identified the key environmental, health, and safety research needs for engineered nanomaterials. One of the key research needs identified was the development of analytical methodology for characterizing nanomaterials in environmental matrices. In this study, aqueous fullerene suspensions were formed at pH's of 4, 7, and 10 in 10mM NaCl equivalent using the extended stirring technique, which does not employ organic solvents, as this technique is more representative of actual environmental conditions. Suspensions were also formed using ground and surface waters. The suspensions were then characterized for fullerene mass concentration, particle size, morphology, and surface potential (zeta potential). Fullerene mass concentration was determined by extracting the fullerenes from the aqueous phase using a liquid-liquid extraction procedure. Fullerenes in the extract were then separated and quantitated by HPLC-UV and HPLC-MS. Fullerene particle size analysis was achieved using dynamic light scattering, electrophoretic mobilities of fullerene aggregates were measured using laser Doppler velocimetry, and particle size and morphology were evaluated using atomic force microscopy (AFM) and transmission electron microscopy (TEM).