Processes > Inverse modelling

How to add Fertilizer formular in the Phreeqc.dat Database for Inverse modelling

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evansmanu:
Dear David,

Thanks for the help. Now I have the below as the sorbed ions, and I want to know how it is interpreted. This is my first time running surface complexation. Does it mean that given the initial conditions of           Hfo_sOH        6e-1   600   1 and  Hfo_wOH        3e-4, an amount of 3.3181e-03 moles of Ca were sorbed onto the surface? I worry about the amount of Na, Mg, K, and Fe, which looks unrealistic. Is there any better interpretation, or did I do something wrong?

My objective is to reduce the Ca concentration in my solution to mimic the reference Ca, which is in the order of e-04

Ca             Na             Mg              K             Fe
3.3181e-03     2.0000e-99     2.0000e-99     2.0000e-99     2.0000e-99

Regards,

dlparkhurst:
You do not have the correct formulas for the sorbed species.

Here is your surface in equilibrium with an arbitrary solution containing Ca, Mg, Na, K, and Fe. Note that there are no sorption reactions (no surface species) for Na and K. Look at the exact formulas of the surface species.

--- Code: ---Surface 1.

Diffuse Double Layer Surface-Complexation Model

Hfo
5.469e-04  Surface charge, eq
8.796e-02  sigma, C/m²
1.385e-01  psi, V
-5.389e+00  -F*psi/RT
4.566e-03  exp(-F*psi/RT)
6.000e+02  specific area, m²/g
6.000e+02  m² for   1.000e+00 g

Hfo_s
6.000e-01  moles
Mole                     Log
Species               Moles    Fraction    Molality    Molality

Hfo_sO-           2.509e-01       0.418   2.509e-01      -0.600
Hfo_sOFe+         2.506e-01       0.418   2.506e-01      -0.601
Hfo_sOH           9.752e-02       0.163   9.752e-02      -1.011
Hfo_sOH2+         8.682e-04       0.001   8.682e-04      -3.061
Hfo_sOHCa+2       1.265e-04       0.000   1.265e-04      -3.898

Hfo_w
3.000e-04  moles
Mole                     Log
Species               Moles    Fraction    Molality    Molality

Hfo_wO-           2.060e-04       0.687   2.060e-04      -3.686
Hfo_wOH           8.004e-05       0.267   8.004e-05      -4.097
Hfo_wOFeOH        1.131e-05       0.038   1.131e-05      -4.947
Hfo_wOFe+         1.919e-06       0.006   1.919e-06      -5.717
Hfo_wOH2+         7.126e-07       0.002   7.126e-07      -6.147
Hfo_wOMg+         6.159e-08       0.000   6.159e-08      -7.210
Hfo_wOCa+         3.441e-09       0.000   3.441e-09      -8.463

--- End code ---

Another way you can calculate the total moles of an element sorbed on the Hfo surface is with the Basic function SURF.

PUNCH SURF("Ca", "Hfo") is equal to the sum of Hfo_wOCa+ and Hfo_sOHCa+2 in moles (not moles/kg water). PUNCH SURF("Ca", "Hfo")/TOT("water") would be moles per kg water.