Ambiguity in determining H2 adsorption capacity of carbon fiber by pressure technique

Carbon fibers obtained by pyrolysis of cotton fibers gives 8.75 wt% hydrogen adsorption if tapping method is used to calculate specific density of carbon fibers while specific density by water displacement methods give a very low value of hydrogen adsorption 0.09 wwt% for the same carbon fibers. It is suggested that either we should establish which method should be used for calculate the specific density of carbon fibers or we should develop a technique to measure hydrogen adsorption which does not need the specific density of carbon.212