Abstract: A BET adsorption apparatus with a high precision differential pressure sensor, which small laboratories can afford, for the use of measurement of internal diffusivity and micropore size distribution (mPSD) of microp orous powders is described. The apparatus is based on gas uptake rate measurem ents and adsorption manometry for measuring internal diffusivity and mPSD.

Key words: microporous powder, diffusivity, micropore size distribution