The invention generally relates to purification of carbon nanomaterials, particularly
fullerenes, by removal of PAHs and other hydrocarbon impurities. The inventive
process involves extracting a sample containing carbon nanomaterials with a solvent
in which the PAHs are substantially soluble but in which the carbon nanomaterials
are not substantially soluble. The sample can be repeatedly or continuously extracted
with one or more solvents to remove a greater amount of impurities. Preferred solvents
include ethanol, diethyl ether, and acetone. The invention also provides a process
for efficiently separating solvent extractable fullerenes from samples containing
fullerenes and PAHs wherein the sample is extracted with a solvent in which both
fullerenes and PAHs are substantially soluble and the sample extract then undergoes
selective extraction to remove PAHs. Suitable solvents in which both fullerenes
and PAHs are soluble include o-xylene, toluene, and o-dichlorobenzene. The purification
process is capable of treating quantities of combustion soot in excess of one kilogram
and can produce fullerenes or fullerenic soot of suitable purity for many applications.
