sorption of neutral species- Kd surface datasets in Minteq

[Tom Meuzelaar]

Hi Brian:

I'm modeling simple linear selenium sorption in X1T using v. 11.0.4, and the Minteq database. I've created a surface dataset (attached 'Kd_modified...' with Kd values for several selenium species. It works fine until I add a neutral species with '(aq)' suffix. Then I get the attached error- this occurs in both React and X1T.

I haven't tried replicating with thermo.dat, but I'm wondering if the extra space between species and '(aq)' in Minteq is causing the problem. Perhaps it's something else I've overlooked.

Thanks in advance,

Tom

Kd_modified_Se_w_neutral_species.sdat

[Brian Farrell]

Hi Tom,

 

Yeah it looks like the space before the "(aq)" in CaSeO4 (aq) in the reaction to form the surface species is problematic. I'll talk with the team and see what can be done about it. In the meantime, you can remove the space from CaSeO4 (aq) in thermo_minteq.tdat, then remove it from the reaction for the surface species. Luckily you're dealing with an aqueous species, not a basis species, otherwise there would be more places to make the change. I think the space in the name of the surface species itself is okay, though. After these quick edits to the thermo and surface datasets I can type a command (with quotes) like explain ">CaSeO4 (aq)" and get the expected results.

 

Thanks for bringing this to our attention.

 

Best,

Brian

[Tom Meuzelaar]

Thanks Brian- I think we'll wait for the patch. We've got neutral species for numerous metals; I tried a quick global search and replace in the Minteq thermo dataset- X1T does indeed accept the revised thermo database and the surface dataset with neutral species, but renaming the revised minteq thermo database causes errors with how the alkalinity constraint is applied. I could leave the database name untouched, but then we have problems that will cascade through a number of our other models.

 

Tom

[Brian Farrell]

Hi Tom,

With the release of GWB 2023, spaces are allowed in the name of any species in the dataset, basis or secondary. When such a species appears in a reaction, or in a virial pair or triplet, it should appear within quotes in that part of the thermo dataset.

For example, the entry for the reaction

>CaSeO4 (aq) = CaSeO4 (aq)

should appear as:

>CaSeO4 (aq)
    charge=    0     mole wt.=   183.0376 g
     1 species in reaction
        1.000 "CaSeO4 (aq)"
     Kd= .01471

Regards,
Brian