A highly improved method for purification of fullerenes applicable to large-scale production Original Research Article

Purification of fullerenes was accomplished by filtration of fullerene extract through a thin layer of activated carbon. Under the optimum conditions, chlorobenzene was used as eluent to diminish the volume of solvent remarkably. The thickness of the carbon layer was only 3–17 mm (activated carbon/fullerene mixture (w/w)=1/3–1/10) enough to obtain pure C60 in good yield. The method presented here is much more convenient than column chromatography commonly used so far and can be applicable to large-scale production of pure C60 and C70. From a mechanistic point of view, fullerenes are considered to be discriminated in the activated carbon pores which have a little larger diameter than the size of fullerenes (1.0–2.0 nm) by π–π interaction between fullerene surface and fused aromatic rings composing the pores.