[Pourbaix diagram for Carbon Redox]

Hi,

I followed the guide and I know how to make an Eh/pH diagram for metal ions, but I'm at a loss for how to do it for carbon. I would like to have it plot for the different redox species of carbon, like methane, carbon monoxide, and CO2. Is that possible?

Thanks,

Ellie H. 

[Trying to calculate pH of solution at temp with gas addition]

Hi Brian, So I got the thing mostly working, and was wondering what the difference is for the iterations in the react output file. I've noticed that the calculated pH from the first iteration and the final iteration can be drastically different. Is the last iteration the most accurate? Or do I average the hundred iterations? Thanks

[Trying to calculate pH of solution at temp with gas addition]

Hi Brian,

 

Sorry to bother again. One thing I'm running into is not seeing all of my components that I need for the system listed when I try to input them into Spec8. I'm missing a sulfur species, specifically sulfide. Is there a way to add this? Or am I not supposed to add it if it's not available? 

Edit: I decoupled the sulfate/sulfide. That let me add it back in, sorry for the spam!

[Trying to calculate pH of solution at temp with gas addition]

Thanks! The relevant sections in the guide is extremely helpful!

Ellie H.

[Trying to calculate pH of solution at temp with gas addition]

Hi, 

I'm brand new to geochemist workbench and I'm trying to figure out the best way to run this simulation. I'm trying to simulate the pH of a solution after I add a CO2 headspace at temperature.

The experimental setup is as follows: 

I mix 3 solutions, 10 mL of iron (ii) ph 8, 10 mL of sulfide pH 11, and 2.5 mL of nickel pH 8 in an argon hood. The iron, nickel and sulfide forms a ppt. I then add a some mL of CO2 headspace at room temp. Then the vials are stored in an 80 degree oven. 

What I'm struggling with is that each vial will have a different amount of CO2, but I want them to end up all at the same pH once at temp. I could adjust the pH at room temp after adding the CO2, but I expect the room temperature pH to be different than the pH at 80C. I was hoping to use geochemist workbench to model the pH of each vial at the final CO2 headspace and temp, and then figure out how much base to add to each vial to get it to pH 9.

Is this something that can be done in the program? I've been reading the tutorials, but I'm not quite sure how to best execute this. I'm also not sure the pH calculations in the program take into account temperature. 

 

Thanks!