(407c) Measurement of the Density of Microporous Materials Needed to Convert Net Adsorption to Absolute Adsorption

In high pressure adsorption measurements it is possible to convert net adsorption to absolute adsorption by determining the density of the solids which includes the volume of the micropores [1]. The most direct way to measure this density is by means of mercury intrusion porosimetry. In this contribution we develop an alternative methodology which allows to determine the same density using standard pycnometry.

Results for both helium and water pycnometry are presented for different hydrophilic and hydrophobic commercial pelletized materials which confirm that the density of microporous materials needed to convert net adsorption to absolute adsorption can be measured without the use of mercury.

The general conclusions that can be drawn are that helium pycnometry provides reliable results while water pycnometry requires careful pre-treatment of the samples in order to yield the correct densities.

EU IRSES Grant 295156 - Offshore Gas Separations (OFFGAS) is gratefully acknowledged.

[1] S. Brandani, E. Mangano, and L. Sarkisov. Net, excess and absolute adsorption and adsorption of helium. Adsorption, 22(2), 261-276.