Krypton for Low Surface Area Determination

The use of krypton or argon rather than nitrogen for adsorbate improves the accuracy of low specific surface area measurements.

Assume the sample has a total surface area of 1 m2 and the volume of the sample tube is 20 cm3. The saturation pressure for nitrogen is about P0(N2) = 760 torr and for krypton it is P0(Kr)= 2.5 torr at liquid nitrogen temperature (assuming a super-cooled liquid state for the krypton).

The single-point BET equation for those gases yields:

0 0

Post a comment