Surface species reaction is not charge balanced

[CShort]

I'm working on adding ferrihydrite sorption parameters to the existing FeOH sorption database, but for some reason my reaction, which I believe is charge balanced, throws an error saying that it is not.

 

I'm attempting to add parameter >(s)FeOHRa++, charge = 2, mole weight = 298.8543, log k = -6.66, dlogk/dt = 0, with >(s)FeOH = 1 and Ra++ = 1.

 

Do you have any suggestions here on where I've gone astray? If I run a React sorption model with the equation as written, does GWB still consider it?

 

Edit: I've added Ra++ to the existing Minteq database, and it's charge is set at +2, molar mass 226, element Ra.

 

Thanks,

Clark

[Brian Farrell]

Hi Clark,

 

The Ra++ in your reaction doesn't look like it's being recognized as an actual species, so I'm guessing it's +2 charge isn't being considered in the reaction. Did you originally use TEdit or a text editor to add this surface reaction? The thermo_minteq.tdat dataset doesn't include any Radium species, but you can certainly add them then make sure that modified dataset is being used to provide all the dissolved and mineral species necessary for your custom surface dataset. You can check the thermo dataset that's being read with your surface dataset by going to the Header pane of TEdit and looking at the "Thermo data" entry. If necessary, you can load a different dataset, such as your modified minteq dataset with Ra, by clicking the Browse button.

 

Hope this helps,

 

Brian Farrell

Aqueous Solutions LLC

[CShort]

Nailed it - just needed to change the thermo dataset path in the header. Thanks!

[Brian Farrell]

Glad to hear that took care of the problem.

 

Cheers,

Brian