According to the Clausius-Clapeyron equation, the isosteric heat of adsorption (DH) can be calculated as:

DH / R = (d ln p)/(d 1/T)

Then, you need to make a plot of (ln p) as a function of (1/T) at the same loadings.

As you can see, this is easy to do when you obtain the full isotherm at different temperatures, which is very difficult to do with data obtained from a TGA.

You need the adsorption isotherm at (at least) one more temperature. See this discussion:

https://www.researchgate.net/post/How_can_I_calculate_the_heat_of_adsorption_using_CO2_adsorption_isotherms_collected_at_273_and_298_K_temperature

or, since some TGA allows through thermocouples installed in the sample and in the reference acting as a simple DSC, try to calculate the heat of adsorption directly as a first approximation.

1. Logic of the Second Law of Thermodynamics: Subjectivism, Logical Jump, Interdisciplinary Argumentation.

2. New thermodynamics pursues universality, two theoretical cornerstones:

2.1 Boltzmann formula: ro=A*exp(-Mgh/RT) - Isotope centrifugal separation experiments show that it is suitable for gases and liquids.

2.2. Hydrostatic equilibrium: applicable to gases and liquids.

3. The second and third sonic virial coefficients of R143a derived from the new thermodynamics are in agreement with the experimental results.

3.1. The third velocity Virial coefficient derived is in agreement with the experimental data, which shows that the theory is still correct when the critical density is reached.

4. See Appendix Pictures and Documents for details.

You need at least 3 temperatures to get reliable isosteric heat of adsorption data. So you need one temperature in between 0 and 25 say 15 degrees or higher than 25 say 35 degrees to get the true isosteric heat.