[Residuals too large]

I have a similar problem, please see the attachment.

Thanks

As_pH=6.rea

[arsenic speciation]

Hi Brian,

 

Then, How do we input the concentration in Gss ? Now we have the total concentration of Se, but the species can be selected in the basis species were SeO3--, SeO4-- and Se-- .

 

 

Regards

 

Tianwei

[About kinetic pyrite oxidation]

Hi Brian,

 

Thanks, I will contact with the sales department. In addition, I am a little confusing with this example discussed here. As we knew, when Logk>0, the reactions will occurs spontaneously, however, when Logk < 0, the reactions will not occurs at normal conditions. As for Eq.1 above, its logk <0 which can be directlly got using Rxn, then it seems that it doesn't make sense to use it here. Also, I think that Rxn is a very convenient tool by which we can get the Log k of a reactionand easily to determine if the reaction will be happened . Am I right ?

 

I will be very grateful if you could give me some advice on my above qustions.

 

Many thanks and best regards

 

Tianwei

[simple question]

Hi Brian,

 

I got it, Thanks a lot.

 

 

Tianwei

[About kinetic pyrite oxidation]

Hi Brian,

 

Also, I need to update the GWB from 9 version to 10, What should I do next ?

 

Thanks

 

Tianwei

[simple question]

Hi Brian,

 

I attached the script file for tracing the reaction path. As I said before, I could not get the same results like Fig.15.8 in book 'Geochemical and Biogeochemical Reaction Modeling' written by Craig M. Bethke. I am confused, could you tell me why?

 

 

Best regards

 

 

Tianwei

Ch15_pyrite-modified.rea

[arsenic speciation]

Hi Brian,

 

I am a little confused about definition on 'component' and 'basis species' in GWB. What's the differences between them?

 

 

Regards

 

Tianwei

[arsenic speciation]

Hi Tom,

 

How to convert the total As concentration to the arsenic basis species? Since, usually ,the data we get from labaoratory is the total concentration.

 

 

Thanks

 

Tianwei

[simple question]

Hi Brian,

 

Thanks for your quickly reply.

 

For your replying to question 1, I need to think it over, it was really complicated.

For your replying to question 2, I know this and i run the model successfully, but the result (the graph) I got was different from that in tutorial(in "using GWB"), i wonder if my input script file is the same as yours, could you send me the input script file you used in tutorial (part "How do I add a reaction trace "in "Using GWB")? or tell me which file was that you used in install directory.

 

Regards

 

Tianwei

[About kinetic pyrite oxidation]

Hi Brian,

 

It seems the reaction described by the eq.1 was not spontaneous, because of its logk<0 which could be directly got by Using Rxn, Thus, is there any sense using eq.1 to calculate pyrite oxidation?

 

 

Regards

 

Tianwei

[simple question]

Hi,

 

I have three simple questions as follows:

 

1. How can I model Zero Valent Iron in REACT?(Since there only Fe²⁺ Or Fe³⁺ that could be selected in basis species)

 

2. How do I add reaction trace? I cannot get the results like that from the tutorial(in "Using GWB"), I did not know which input file was that you used in REACT.

 

3 What does "Fe(OH)3(ppd)" mean?

 

Thanks a lot

 

Tianwei