Interactions of clay minerals and a layered double hydroxide with water stable, nano scale fullerene aggregates (nC 60)

Abstract

The research presented details on specific interactions of underivatized C 60 as an aggregate suspension in water (termed nC 60) with clay minerals (montmorillonite and kaolinite), and a synthetic layered double hydroxide LDH. Batch and 1-D flow-through column interactions were analyzed via UV/Vis spectroscopy, X-ray diffraction analysis, and transmission electron microscopy. Results indicate that nC 60 suspended in water interacted with all the solid materials (‘clays’) studied. The LDH, with a net positive surface charge, has the greatest capacity to associate with the negatively charged nC 60, capable of adsorbing 18% w/w. Column studies support sorption isotherm data, with LDH retarding nC 60 transport > 30 times more, in relative terms, than montmorillonite or kaolinite. Findings suggest that specific material interactions are primarily dominated by available surface area and electrostatic interaction at charged surfaces. Intercalation was not observed. These results have implications not only for understanding fullerene transport in the subsurface, but also towards engineering effective barriers for safe storage and disposal.