Acid on exchanger in T&H database

[peterwadeuk]

Greetings good people,

I am attempting to model ion exchange between clay sites and interstitial soil pore waters, and between organic material and soil pore waters.

Which is why I am using the T&H.dat database.

Can anyone tell me why the contribution of H-X has been commented out of the database?

All the best,
Peter

[dlparkhurst]

If you are talking about the exchange reaction with H+, I think there is a lot of uncertainty in the experiments as to whether H+ is exchanged, or H+ is dissolving the exchange material.  I would look in Appelo and Postma (Geochemistry, Groundwater and Pollution) to see to whether they present a log K for the reaction. The log Ks in the databases are likely similar to their numbers.

[Pak]

I do not know much about mineralogy but if your clay has Illite, Montmorillonite. You will find exchange and sorption constants in papers of Bradbury, M. H.& Baeyens, B.  (2009a,b, 2005)