Experimental Apparatus for Characterizing the Internal Diffusivity of Microporous Powders

The characterization of the micropore range in porous powders requires sophisticated apparatuses, which limits their thorough characterization to large laboratories. We describe a modification of a BET adsorption apparatus, in which the key instrument is a high precision differential pressure sensor, which even small laboratories can afford, that can be used to measure the internal diffusivity and micropore size distribution (mPSD) of microporous powders. The apparatus is based on the conventional gas uptake rate measurement and adsorption manometry for measuring diffusivity and mPSD, respectively. Numerical simulations of the measurement and uptake rate were used to analyze the apparatus.