Dual gas analysis method

In the dual gas analysis method, two isotherms measured on the same sample and two corresponding kernels are used6, 8, 11. With this advanced capability, the two kernels are simultaneously fitted to two independently measured isotherms differing in adsorptive and/or temperature.

Example of the PSD analysis using the simultaneous fit of N2 and CO2 kernels to experimental isotherms

N2 isotherm including the low-pressure range
N2 isotherm measured only in the mesopore pressure range

The dual gas analysis method with O2 and H2 is advantageous over the earlier presented method with N2 and CO2 due to the lower quadrupole moments of O2 and H2. It is also more practically convenient because the same cryogen, liquid N2, is used for both analyses.

Example of the PSD analysis using the simultaneous fit of O2 and H2 kernels to experimental isotherms

O2 isotherm including the low-pressure range
Isotherm pressure of H2 is in atm.
O2 isotherm measured only in the mesopore pressure range