How to simulate the surface complex in PetraSim
Hello, everyone,
Sorry to disturb you. I wanted to simulate the surface complex between aqueous Europium+3 and -S-sOH and -S-wOH (the defined group) in clay. I added the surface complex formula in the database, and selected the Eu+3, -S-sOH and -S-wOH as the primary species. Now I don't know how to set up the concentration of -S-sOH and -S-wOH in initial and boundary conditions, since it is a solid group in clay.
When I set up a low initial concentration for -S-sOH and -S-wOH arbitrarily, I found the model could not run. So I was wandering how to revise my model. Thank you!
I would appreciate if someone helps me to solve this problem. Thank you!
Best regards,
Lang
2 replies
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Hi Lang, the initial concentration of S-SOH is internally computed from input site sensity (mol_sites/m2, entered on the primary S-SOH species record) and sorption surface area (in cm2/g or m2/m3, entered in the surface adsorption zones). The S-SOH concentration value that needs to be input is just a place holder. Just use some small value (like 1e-3) for both the trial and "true" value. If it does not converge, try increasing or reducing the trial value, because that one should matter if I recall correctly. - Nic
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Dear Nic,
Thank you for your very helpful reply.
Best regards,
Lang