Problems on React input

[skyrock79]

Hello Tom,

 

I am trying to use React to model the reaction of zero valent Fe nanoparticles with bicarbonate in water. I made the input of basis as: HCO3-,Fe (mineral), Na+, Cl-, H+. In the reactant, i chose kinetic mineral as 0.5g Fe, specified surface area (20m2/g) and assumed one rate constant (1e-5). When I ran the script. It said O2 has to be in the basis. So I added O2 into basis. Because my system is essentially anoxic, I made the O2 concentration very low (1nmolal). However, the scripts seemed still to be wrong. It said residual are too large and there is no normal iteration.

Can you give me some suggestions to fix it? I attached my script.

 

Thanks

 

Dimin

React_Fe_CO3.rea

[Tom Meuzelaar]

Hello Tom,

 

I am trying to use React to model the reaction of zero valent Fe nanoparticles with bicarbonate in water. I made the input of basis as: HCO3-,Fe (mineral), Na+, Cl-, H+. In the reactant, i chose kinetic mineral as 0.5g Fe, specified surface area (20m2/g) and assumed one rate constant (1e-5). When I ran the script. It said O2 has to be in the basis. So I added O2 into basis. Because my system is essentially anoxic, I made the O2 concentration very low (1nmolal). However, the scripts seemed still to be wrong. It said residual are too large and there is no normal iteration.

Can you give me some suggestions to fix it? I attached my script.

 

Thanks

 

Dimin

 

Hi Dimin:

 

Looks like you're using a modified version of the extended LANL database- can you attach this? If it's proprietary, you can email it to me.

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

[skyrock79]

Hi Dimin:

 

Looks like you're using a modified version of the extended LANL database- can you attach this? If it's proprietary, you can email it to me.

 

Regards,

 

Tom Meuzelaar

RockWare, Inc.

 

Hi Tom,

 

It seems i am not permitted to upload data file. I sent to you via email.

Thanks very much!

 

Dimin

[Tom Meuzelaar]

Hi Dimin:

 

It looks like the first problem is a charge balance issue. You've chosen to balance on Cl-, but the water defined in the Basis has more anions than cations. If you remove Cl- and balance on Na+, the solution converges.

 

Beyond that, the fast rate constant and the large surface area you've specified causes the reaction to complete within a fraction of a second, rather than over a period of 14 days.

 

Hope that helps,

 

Tom