Surface Complexation with gas phase

[dat]

Hi,

I am modelling surface complexation reactions with Quartz, Kaolinite, brine and with hydrogen. How to incorporate my gas phase into surface reactions.

When I am defining surface to gas, do I have to define H2(g), H2(aq) and H+ because all of these will react in the system? If that is so how to do that?

I plan to use core10.dat. Could you please have a look at my code? Appreciate your help.

Code: [Select]

SOLUTION 1
units mmol/kgw
Temp 80
ph 6.33
Na 604.61
Cl 685.47
Ca 14.97
Mg 64.17
S(6) 35.60
water 0.02

GAS_PHASE 1
    -fixed_pressure
    -pressure 197
    -volume 1
    -temperature 80
    H2(g)        197

EQUILIBRIUM_PHASES 1
Kaolinite 0 5.42E-07
Quartz 0 1.52E-04
K-feldspar 0 1.33E-06
Dolomite 0 8.13E-07
Albite 0 4.58E-07

SURFACE_MASTER_SPECIES

Surf_al Surf_alOH
Surf_si Surf_siOH
Surf_qs Surf_qsOH


SURFACE_SPECIES

Surf_alOH = Surf_alOH
-cd_music 0 0 0
log_k 0
Surf_siOH = Surf_siOH
-cd_music 0 0 0
log_k 0
Surf_alOH + H+ = Surf_alOH2+
-cd_music 1 0 0
log_k 0.8
Surf_siOH + H+ = Surf_siOH2+
-cd_music 1 0 0
log_k 0.8
Surf_alOH = Surf_alO- + H+
-cd_music -1 0 0
log_k -7
Surf_siOH = Surf_siO- + H+
-cd_music -1 0 0
log_k -7
Surf_alOH + Ca++ = Surf_alOCa+ + H+
-cd_music -1 2 0
log_k -6
Surf_siOH + Ca++ = Surf_siOCa+ + H+
-cd_music -1 2 0
log_k -6
Surf_alOH + Mg++ = Surf_alOMg+ + H+
-cd_music -1 2 0
log_k -5.55
Surf_siOH + Mg++ = Surf_siOMg+ + H+
-cd_music -1 2 0
log_k -5.55
Surf_qsOH = Surf_qsOH
-cd_music 0 0 0
log_k 0
Surf_qsOH + H+ = Surf_qsOH2+
-cd_music 1 0 0
log_k -1.75
Surf_qsOH = Surf_qsO- + H+
-cd_music -1 0 0
log_k -6.75
Surf_qsOH + Ca++ = Surf_qsOCa+ + H+
-cd_music -1 2 0
log_k -5.7
Surf_qsOH + Mg++ = Surf_qsOMg+ + H+
-cd_music -1 2 0
log_k -5.70


SURFACE 1

-sites_units Density
-cd_music
-equilibrate 1
Surf_alOH 5.5
Surf_siOH 5.5
Surf_qsOH 4.6 2.34 0.01
-capacitance 3.098 0.2
END