Real Density of Activated Carbon

Real density is also known as absolute and helium density and is defined as the mass of a unit volume of the solid carbon skeleton, inaccessible to helium. In this method, it is assumed that helium enters the smallest pores present, without being adsorbed. However, it is well documented that helium may be adsorbed in microporous carbons and, consequently, this possibility has to be checked and taken into consideration to give a realistic value. This is not a routine test. The main problem is that commercially available equipment shows a poor reproducibility.