a low - cost and facile method of purifying fullerenes to obtain a preparation enriched in a fullerene of selected molecular weight using activated carbon involves adding a fullerene mixture to the top end of a column comprising activated carbon , passing a solvent in which the selected molecular weight fullerene is soluble through the column , and recovering a fraction enriched in the selected molecular weight fullerene from the bottom end of the column . in addition to activated carbon , the column may further comprise silica gel , diatomaceous earth , or other materials which aid in column packing and eluent flow .