[Acement]

Hi
First sorry for the low level question but I’m stock…

I’m modeling cement paste with PHREEQC and particular binding of different ions in the pore solution. I work with a surface model, with silanol sites. The amount of silanol sites is relative to CSH particle, described as a pure solid phase in the model.

My problem is the literature data of the silanol sites, where I have found estimated values of 4.8 sites/nm^2 and specific surface area of CSH, 250916 m^2/mol. From this one can determine sites/mol, which is relative large number. The problem is that PHREEQC takes the input mol/mol of CSH to determine the amount of surface sites. So how is surface sites related to mol?

Maybe I understand the basic completely wrong and it can’t be done!

Thanks
BR   

[zoork34]

Its possible you could be overthinking this.  The number of sites is equal to the number of silanol groups, so your units are already where you want them to be since a mole of sites is just 6.02x10^23 sites.  So, all you have to do is divide sites/mol by 6.02x10^23 to get moles/mol.  Hope this makes sense.