Introduce substances into solution

[AnnaJulIQ]

Good day,

I have a Water solution with an amount of ions, then I put the values:

Code: [Select]



Water : 117,4177 g

Zn+2 = 0,347604656  (g)
ZnOH+= 0,00085039  (g)
Zn(OH)2= 2,97595E-07 (g)
Zn(OH)3-=6,01526E-13 (g)
Zn(OH)4-2=1,05762E-19 (g)
ZnSO4=0,727048426  (g)
Zn(SO4)2-2= 0,248489841 (g)

Mn+2= 7,54977E-05 (g)
Mn+3= 7,96438E-20 (g)
MnO4-= 6,65126E-14  (g)
(MnO4)-2=2,76661E-18  (g)
MnOH+= 5,39854E-09  (g)
Mn(OH)3-= 5,64196E-31  (g)
MnSO4= 0,000157038 (g)


I know that Zn + 2 can be placed as Zn in solution, like Mn (2) and Mn (3), but the way the other ions were added confused me. How could I add them? I am mainly interested in adding ZnSO4 and Zn (SO4) 2-2

[dlparkhurst]

It is not possible to input individual ions and ion complexes in PHREEQC. It is only possible to input total concentrations of elements or element redox states and let PHREEQC calculate the "Distribution of Species". It is not possible, in general, to analyze the individual ions, so a SOLUTION definition is used to enter concentration values that can be analyzed, like the concentration of Zn measured by induction coupled plasma or atomic absorption spectroscopy and SO4 by ion chromatography.

In your case, you could enter the total amount of Zn, Mn [Mn(2) or Mn(3) are not normally analyzed], and S(6), and PHREEQC would determine the concentrations of aqueous species like Zn+2, ZnSO4, Zn(SO4)2-2, Mn+3, Mn+2. The results depend on the database that you use. phreeqc.dat has a reaction for Zn(SO4)2-2, whereas sit.dat does not, so the output will differ accordingly.

The information that you list looks like output from a geochemical model with some set of reactions and equilibrium constants for the aqueous species. If you use the same reactions and log Ks in a database for PHREEQC, you should get similar results to the ones you list, although the output will be in moles, not grams. Activity coefficients and other model details may differ.