HR: 17:15h
AN: H54C-05    [Abstracts]
TI: Investigation of n-C60 Nanoparticle Transport and Retention in Saturated Porous Media
AU: * Li, Y
EM: yusong.li@tufts.edu
AF: Tufts University, 200 College ave., Medford, MA 02155,
AU: Wang, Y
EM: ywang32@mail.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332,
AU: Pennell, K
EM: kpennell@ce.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332,
AU: Pennell, K
EM: kpennell@ce.gatech.edu
AF: Emory University, Department of Neurology, Atlanta, GA 30332,
AU: Abriola, L
EM: linda.abriola@tufts.edu
AF: Tufts University, 200 College ave., Medford, MA 02155,
AB: Buckminster fullerene (C60), a molecule composed of 60 carbon atoms arranged as a spherical cage, has recently gained wide application in many commercial products. Based on its widespread use, it is likely that C60 will be released into the environment during manufacture, transportation, and/or application. Possessing negligible solubility in water, C60 is capable of acquiring charge and form highly stable nano-scale aggregates (n-C60) in aqueous systems. While the toxicity of C60 nanoparticles has recently been explored, our current understanding of n-C60 fate and transport in subsurface environments is still quite limited. In this study, experimental and mathematical modeling studies were performed to investigate the transport and retention of n-C60 nanoparticles in water-saturated porous media. A series of transport experiments was conducted at several pore-water velocities in glass columns packed with various size fractions of Ottawa sand. A mathematical model that incorporates non-equilibrium attachment kinetics and a maximum retention capacity was developed to simulate n-C60 transport and retention in porous media. The numerical model is able to simulate both the effluent concentration and particle retention profiles. Experimental and simulation results suggest that the retention of n-C60 aggregates is strongly dependent on porous media surface area and flow rate. The extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which includes van der Waals, electro- static repulsion, and hydrophobic interaction forces, was used to evaluate potential mechanisms governing n- C60 attachment. This analysis suggests that a sizable energy barrier exists between n-C60 aggregates and the Ottawa sand surface, with a small secondary minimum attraction region. Attachment rate coefficients derived from secondary energy minimum theory were found to be in close agreement with those fit to retention data. . Maximum retention capacity was found to be correlated with system Peclet number and porous medium grain size.
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1847 Modeling
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting