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Keywords:

  • Fullerene nanoparticles;
  • nC60;
  • Contaminant mobilization;
  • Enhanced transport;
  • Porous media

Abstract

Fullerene nanoparticles (nC60) in aqueous environments can significantly enhance the transport of hydrophobic organic contaminants by serving as a contaminant carrier. In the present study, the authors examine the effect of the solvent-exchange process on nC60 aggregate formation and, subsequently, on nC60's contaminant-mobilizing capability. A series of nC60 samples were prepared using a modified toluenewater solvent-exchange method through the inclusion of a secondary organic solvent in the phase transfer of molecular C60 in toluene to nC60 in water. Two groups of solvents—a water-miscible group and a non–water-miscible group—of varied polarity were selected as secondary solvents. The involvement of a secondary solvent in the phase transfer process had only small effects on the particle size and distribution, ζ potential, and mobility of the nC60 products but significantly influenced the capability of nC60 to enhance the transport of 2,2′,5,5′-polychlorinated biphenyl (PCB) in a saturated sandy soil column, regardless of whether the secondary solvent was water-miscible or non–water-miscible. The two groups of secondary solvents appear to affect the aggregation properties of nC60 in water via different mechanisms. In general, nC60 products made with a secondary water-miscible solvent have stronger capabilities to enhance PCB transport. Taken together, the results indicate that according to formation conditions and solvent constituents, nC60 will vary significantly in its interactions with organic contaminants, specifically as related to adsorption or desorption as well as transport in porous media. Environ. Toxicol. Chem. 2013;32:329–336. © 2012 SETAC