Madi

[Madi]

Hi,

I wanted to plot the pH-eH diagram using arsenic. I know the GWB2023 has only As(OH)4- in the database. I have the followings arsenicals: As(3) , H3AsO3 , H2AsO3- , H4AsO3+ , HAsO3-2 , AsO3-3 , AsS(OH)(HS), As3S4(HS)2-, As(5) , H2AsO4- , HAsO4-2 , H3AsO4 , AsO4-3. Which one of them am I going to input into GWB since they are not in the database? I look forward to reading you soon.

Regards,

Madi

[Jia Wang]

Hello Madi,

Could you provide some more detail as to what you are having issues with and also what you have tried so far? Are you trying to add species to the dataset? Or, are you have trouble setting up an Eh-pH diagram in a specific application?

If this is the first time you're working with the software, I would recommend that you review the GWB Essentials guide. In particular, if you are looking to create Eh-pH diagrams in Act2, you can review chapter 5. Act 2. Species available in the calculation will depend on the database loaded. The software by default uses thermo.tdat, which As(OH)4- is entered as a basis species along with AsH3(aq) and AsO4--- as redox species. Other aqueous reactions involving arsenic species are considered secondary species in this dataset. You can easily view the reactions in any GWB dataset using the TEdit application. For detailed information and examples, please see chapter 9 Using TEdit in the same guide.

Best regards,
Jia Wang
Aqueous Solutions LLC

[Madi]

Hi Jia,

Thank you so much for the information you provided, it was beneficial. Now I want to know how to plot data on the Eh-pH diagram (e.g., stars on the Eh-pH diagram in the attached document).

Pourbaix diagram.docx