Adsorption Enthalpy from Thermochromatographic Experiments

Now we can use the formulae for entropy to estimate the adsorption enthalpy on the basis of the experimental constant and the Third Law-like procedure. 

In the case of IC experiments, assuming mobile adsorption, from Eqs. 5.2, 5.9 and 5.33 we obtain 

the result does not depend on the accepted ratio V/A. 

Analogous expressions for the localized adsorption, which follow from Eqs. 5.42 and 5.12, are  

It can be checked that the difference in the values provided by Eqs. 5.48 and 5.49 is the same as between the reduced entropy values, except for the sign. 

---

Bachmann and co-workers interpreted their data for molecules halides in columns loaded with alkaline halides as evidence for the formation of complexes between the adsorbate and the crystalline halide. Such complexes were considered for application in radiochemical separations earlier by Zvara and co-workers in [3,13,14], who estimated the adsorption enthalpies from the rough adsorption isobar obtained in thermochromatographic experiments using Eq. 5.14. The adsorption enthalpy for NbCls on KC1 [14] is intermediate between the data of Table 5.1 for the adsorbents NaCl and CsCl, so that the results of the two groups are consistent. 

---