Hi
I am simulating P sorption in a sandy soil with surface charge properties dominated by FeOH minerals (goethite and haematite) and amorphous hydrous oxides. I have calculated sorbed P in PHREEQC using the function SURF("P", "Hfo") and the output represented very closely the measured P sorption isotherm based on the contribution of strong and weak Hfo sites (see below)
SURFACE 0 Strong and weak adsorption sites - iron oxides
Hfo_sOH 0.0313 6.85 5.353
Hfo_wOH 0.0788
I am enquiring if this same function is used in HP1 as when I run HP1 values for Sorbed P are not written as output using the following lines:
USER_PUNCH 1
-headings SorbP
-start
10 PUNCH SURF("P", "Hfo")
-end
end
thanks for any assistance.
ian