Conceptual Models > Program coupling
Inhibiting Redox Reaction
GeeqC:
Trying to set boundary conditions in PhreeqcRM for deep porewaters with methane, I realized that methane is being consumed while sulphate reacts to sulphide.
Based on another forum post, elements with different redox states (e.g. S(6), S(-2), C(-4), Fe(2), Fe(3)) should not automatically react in an input solution. However, somewhere in the simulation, presumably during RunCells, solutions get redox equilibrated.
This is a fundamental problem (apparently not only in my model), because many redox reactions are kinetically inhibited under Earth surface conditions.
Ideally, it would be preferrable if all redox reactions could be switched off by default. Single reactions could then be allowed individually, according to their specific kinetics.
If this is not possible, I suppose kinetics would have to be defined for every possible redox reaction in the solution, setting a k = 0 for those reactions that are inhibited.
dlparkhurst:
Well, I am glad to see that you are beginning to think a bit about geochemistry.
In many cases, redox equilibrium is a reasonable way to approach a system. In detail, there may be kinetic transformations, but in general, you do not find oxygen and sulfide coexisting. Similarly, most sulfate tends to be reduced before methane forms. So, until you have a good reason to expect significant redox disequilibria, you should start with the simplest approach, which is redox equilibrium.
It is possible to decouple redox states, but it is not particularly easy. The database Amm has removed N(-3) and defined Amm (equivalent to NH3). In this case N(-3) cannot be formed by reduction of N(5), N(3), or N2. Amm can only be formed by a kinetic reaction that transforms NH3 to Amm. Similarly, but a more common reaction, nitrification (N(-3) to N(5)) can only be simulated by a kinetic reaction.
If you want to decouple all redox states, you will have many kinetic reactions to deal with. Moreover, it will be difficult to maintain thermodynamic consistency. For example, how do you ensure that you are not making methane and nitrite at the same time, which would not be reasonable?
As I said, the Amm.dat datbase separates ammonium from the rest of the nitrogen system. The new database stimela.dat has some redox decoupling. Here is a database that completely decouples all redox states.
You are welcome to do whatever you see fit. Good luck.
--- Code: ---SOLUTION_MASTER_SPECIES
H H+ -1 H 1.008
H(0) H2 0 H
H(1) H+ -1 0
Hzero Hzero2 0 Hzero 1
E e- 0 0 1
O H2O 0 O 16
O(0) O2 0 O
O(-2) H2O 0 0
Ozero Ozero2 0 Ozero 16
Ca Ca+2 0 Ca 40.08
Mg Mg+2 0 Mg 24.312
Na Na+ 0 Na 22.9898
K K+ 0 K 39.102
Ferrous Ferrous+2 0 Ferrous 55.847
Ferric Ferric+3 -2 Ferric 55.847
Manganous Manganous+2 0 Manganous 54.938
Manganic Manganic+3 0 Manganic 54.938
Al Al+3 0 Al 26.9815
Ba Ba+2 0 Ba 137.34
Sr Sr+2 0 Sr 87.62
Si H4SiO4 0 SiO2 28.0843
Cl Cl- 0 Cl 35.453
C CO3-2 2 HCO3 12.0111
C(4) CO3-2 2 HCO3 12.0111
Methane MethaneH4 0 MethaneH4 12.0111
Alkalinity CO3-2 1 Ca0.5(CO3)0.5 50.05
Sulfate SulfateO4-2 0 SulfateO4 32.064
Sulfide HSulfide- 1 Sulfide 32.064
Nitrate NitrateO3- 0 Nitrate 14.0067
Nitrite NitriteO2- 0 Nitrite 14.0067
Nzero Nzero2 0 Nzero 14.0067
Amm AmmH4+ 0 Amm 14.0067
B H3BO3 0 B 10.81
P PO4-3 2 P 30.9738
F F- 0 F 18.9984
Li Li+ 0 Li 6.939
Br Br- 0 Br 79.904
Zn Zn+2 0 Zn 65.37
Cd Cd+2 0 Cd 112.4
Pb Pb+2 0 Pb 207.19
Cupric Cupric+2 0 Cupric 63.546
Cuprous Cuprous+ 0 Cuprous 63.546
SOLUTION_SPECIES
H+ = H+
log_k 0
-gamma 9 0
-dw 9.31e-009
e- = e-
log_k 0
H2O = H2O
log_k 0
Ca+2 = Ca+2
log_k 0
-gamma 5 0.165
-dw 7.93e-010
-millero -19.69 0.1058 -0.001256 1.617 -0.075 0.0008262
Mg+2 = Mg+2
log_k 0
-gamma 5.5 0.2
-dw 7.05e-010
-millero -22.32 0.0868 -0.0016 2.017 -0.125 0.001457
Na+ = Na+
log_k 0
-gamma 4 0.075
-dw 1.33e-009
-millero -3.46 0.1092 -0.000768 2.698 -0.106 0.001651
K+ = K+
log_k 0
-gamma 3.5 0.015
-dw 1.96e-009
-millero 7.26 0.0892 -0.000736 2.722 -0.101 0.00151
Ferrous+2 = Ferrous+2
log_k 0
-gamma 6 0
-dw 7.19e-010
Manganous+2 = Manganous+2
log_k 0
-gamma 6 0
-dw 6.88e-010
Al+3 = Al+3
log_k 0
-gamma 9 0
-dw 5.59e-010
Ba+2 = Ba+2
log_k 0
-gamma 5 0
-dw 8.48e-010
Sr+2 = Sr+2
log_k 0
-gamma 5.26 0.121
-dw 7.94e-010
-millero -18.44 0.0082 -0.0006 1.727 -0.067 0.00084
H4SiO4 = H4SiO4
log_k 0
-dw 1.1e-009
-millero 56 0 0 0 0 0
Cl- = Cl-
log_k 0
-gamma 3.5 0.015
-dw 2.03e-009
-millero 16.37 0.0896 -0.001264 -1.494 0.034 -0.000621
CO3-2 = CO3-2
log_k 0
-gamma 5.4 0
-dw 9.55e-010
-millero -8.74 0.3 -0.004064 5.65 0 0
SulfateO4-2 = SulfateO4-2
log_k 0
-gamma 5 -0.04
-dw 1.07e-009
-millero 9.26 0.284 -0.003808 0.4348 -0.0099143 -8.4762e-005
NitrateO3- = NitrateO3-
log_k 0
-dw 1.9e-009
-millero 25.51 0.1888 -0.001984 -0.654 0 0
H3BO3 = H3BO3
log_k 0
-dw 1.1e-009
-millero 36.56 0.13 -0.00081 0 0 0
PO4-3 = PO4-3
log_k 0
-gamma 4 0
-dw 6.12e-010
F- = F-
log_k 0
-gamma 3.5 0
-dw 1.46e-009
-millero -3.05 0.3276 -0.00352 1.271 -0.074 8.857e-005
Li+ = Li+
log_k 0
-gamma 6 0
-dw 1.03e-009
Br- = Br-
log_k 0
-gamma 3 0
-dw 2.01e-009
-millero 22.98 0.0934 -0.000968 -1.675 0.05 -0.001105
Zn+2 = Zn+2
log_k 0
-gamma 5 0
-dw 7.15e-010
Cd+2 = Cd+2
log_k 0
-dw 7.17e-010
Pb+2 = Pb+2
log_k 0
-dw 9.45e-010
Cupric+2 = Cupric+2
log_k 0
-gamma 6 0
-dw 7.33e-010
H2O = OH- + H+
log_k -14
delta_h 13.362 kcal
-analytical_expression -283.971 -0.05069842 13323 102.24447 -1119669 0
-gamma 3.5 0
-dw 5.27e-009
2H2O = O2 + 4H+ + 4e-
log_k -86.08
delta_h 134.79 kcal
-dw 2.35e-009
Ozero2 = Ozero2
log_k 0
-dw 2.35e-009
2H+ + 2e- = H2
log_k -3.15
delta_h -1.759 kcal
-dw 5.1e-009
Hzero2 = Hzero2
log_k 0
-dw 5.1e-009
H+ + CO3-2 = HCO3-
log_k 10.329
delta_h -3.561 kcal
-analytical_expression 107.8871 0.03252849 -5151.79 -38.92561 563713.9 0
-gamma 5.4 0
-dw 1.18e-009
-millero 21.07 0.185 -0.002248 2.29 -0.006644 -3.667e-006
2H+ + CO3-2 = CO2 + H2O
log_k 16.681
delta_h -5.738 kcal
-analytical_expression 464.1965 0.09344813 -26986.16 -165.75951 2248628.9 0
-dw 1.92e-009
MethaneH4 = MethaneH4
log_k 0
delta_h -61.039 kcal
-dw 1.85e-009
H+ + SulfateO4-2 = HSulfateO4-
log_k 1.988
delta_h 3.85 kcal
-analytical_expression -56.889 0.006473 2307.9 19.8858 0 0
-dw 1.33e-009
HSulfide- = HSulfide-
log_k 0
-gamma 3.5 0
-dw 1.73e-009
HSulfide- = Sulfide-2 + H+
log_k -12.918
delta_h 12.1 kcal
-gamma 5 0
-dw 7.31e-010
H+ + HSulfide- = H2Sulfide
log_k 6.994
delta_h -5.3 kcal
-analytical_expression -11.17 0.02386 3279 0 0 0
-dw 2.1e-009
NitriteO2- = NitriteO2-
log_k 0
-gamma 3 0
-dw 1.91e-009
Nzero2 = Nzero2
log_k 0
-dw 1.96e-009
AmmH4+ = AmmH3 + H+
log_k -9.252
delta_h 12.48 kcal
-analytical_expression 0.6322 -0.001225 -2835.76 0 0 0
-dw 2.28e-009
AmmH4+ = AmmH4+
log_k 0
-gamma 2.5 0
-dw 1.98e-009
-millero 17.47 -0.0034 0.00076 0 0 0
AmmH4+ + SulfateO4-2 = AmmH4SulfateO4-
log_k 1.11
H3BO3 = H2BO3- + H+
log_k -9.24
delta_h 3.224 kcal
F- + H3BO3 = BF(OH)3-
log_k -0.4
delta_h 1.85 kcal
2F- + H+ + H3BO3 = BF2(OH)2- + H2O
log_k 7.63
delta_h 1.618 kcal
3F- + 2H+ + H3BO3 = BF3OH- + 2H2O
log_k 13.67
delta_h -1.614 kcal
4F- + 3H+ + H3BO3 = BF4- + 3H2O
log_k 20.28
delta_h -1.846 kcal
H+ + PO4-3 = HPO4-2
log_k 12.346
delta_h -3.53 kcal
-gamma 4 0
-dw 6.9e-010
2H+ + PO4-3 = H2PO4-
log_k 19.553
delta_h -4.52 kcal
-gamma 4.5 0
-dw 8.46e-010
-millero 33.6 0 0 0 0 0
F- + H+ = HF
log_k 3.18
delta_h 3.18 kcal
-analytical_expression -2.033 0.012645 429.01 0 0 0
2F- + H+ = HF2-
log_k 3.76
delta_h 4.55 kcal
Ca+2 + H2O = CaOH+ + H+
log_k -12.78
Ca+2 + CO3-2 = CaCO3
log_k 3.224
delta_h 3.545 kcal
-analytical_expression -1228.732 -0.29944 35512.75 485.818 0 0
-dw 4.46e-010
Ca+2 + H+ + CO3-2 = CaHCO3+
log_k 11.435
delta_h -0.871 kcal
-analytical_expression 1317.0071 0.34546894 -39916.84 -517.70761 563713.9 0
-gamma 5.4 0
-dw 5.06e-010
Ca+2 + SulfateO4-2 = CaSulfateO4
log_k 2.3
delta_h 1.65 kcal
-dw 4.71e-010
Ca+2 + HSulfateO4- = CaHSulfateO4+
log_k 1.08
Ca+2 + PO4-3 = CaPO4-
log_k 6.459
delta_h 3.1 kcal
Ca+2 + HPO4-2 = CaHPO4
log_k 2.739
delta_h 3.3 kcal
Ca+2 + H2PO4- = CaH2PO4+
log_k 1.408
delta_h 3.4 kcal
Ca+2 + F- = CaF+
log_k 0.94
delta_h 4.12 kcal
H2O + Mg+2 = MgOH+ + H+
log_k -11.44
delta_h 15.952 kcal
Mg+2 + CO3-2 = MgCO3
log_k 2.98
delta_h 2.713 kcal
-analytical_expression 0.991 0.00667 0 0 0 0
H+ + Mg+2 + CO3-2 = MgHCO3+
log_k 11.399
delta_h -2.771 kcal
-analytical_expression 48.6721 0.03252849 -2614.335 -18.00263 563713.9 0
Mg+2 + SulfateO4-2 = MgSulfateO4
log_k 2.37
delta_h 4.55 kcal
Mg+2 + PO4-3 = MgPO4-
log_k 6.589
delta_h 3.1 kcal
HPO4-2 + Mg+2 = MgHPO4
log_k 2.87
delta_h 3.3 kcal
H2PO4- + Mg+2 = MgH2PO4+
log_k 1.513
delta_h 3.4 kcal
F- + Mg+2 = MgF+
log_k 1.82
delta_h 3.2 kcal
H2O + Na+ = NaOH + H+
log_k -14.18
Na+ + CO3-2 = NaCO3-
log_k 1.27
delta_h 8.91 kcal
-dw 5.85e-010
HCO3- + Na+ = NaHCO3
log_k -0.25
-dw 6.73e-010
Na+ + SulfateO4-2 = NaSulfateO4-
log_k 0.7
delta_h 1.12 kcal
-dw 6.18e-010
HPO4-2 + Na+ = NaHPO4-
log_k 0.29
F- + Na+ = NaF
log_k -0.24
H2O + K+ = KOH + H+
log_k -14.46
K+ + SulfateO4-2 = KSulfateO4-
log_k 0.85
delta_h 2.25 kcal
-analytical_expression 3.106 0 -673.6 0 0 0
-dw 7.46e-010
HPO4-2 + K+ = KHPO4-
log_k 0.29
Ferrous+2 + H2O = FerrousOH+ + H+
log_k -9.5
delta_h 13.2 kcal
Cl- + Ferrous+2 = FerrousCl+
log_k 0.14
Ferrous+2 + CO3-2 = FerrousCO3
log_k 4.38
Ferrous+2 + HCO3- = FerrousHCO3+
log_k 2
Ferrous+2 + SulfateO4-2 = FerrousSulfateO4
log_k 2.25
delta_h 3.23 kcal
Ferrous+2 + HSulfateO4- = FerrousHSulfateO4+
log_k 1.08
Ferrous+2 + 2HSulfide- = Ferrous(HSulfide)2
log_k 8.95
Ferrous+2 + 3HSulfide- = Ferrous(HSulfide)3-
log_k 10.987
Ferrous+2 + HPO4-2 = FerrousHPO4
log_k 3.6
Ferrous+2 + H2PO4- = FerrousH2PO4+
log_k 2.7
F- + Ferrous+2 = FerrousF+
log_k 1
Ferric+3 = Ferric+3
log_k 0
-gamma 9 0
Ferric+3 + H2O = FerricOH+2 + H+
log_k -2.19
delta_h 10.4 kcal
Ferric+3 + 2H2O = Ferric(OH)2+ + 2H+
log_k -5.67
delta_h 17.1 kcal
Ferric+3 + 3H2O = Ferric(OH)3 + 3H+
log_k -12.56
delta_h 24.8 kcal
Ferric+3 + 4H2O = Ferric(OH)4- + 4H+
log_k -21.6
delta_h 31.9 kcal
2Ferric+3 + 2H2O = Ferric2(OH)2+4 + 2H+
log_k -2.95
delta_h 13.5 kcal
3Ferric+3 + 4H2O = Ferric3(OH)4+5 + 4H+
log_k -6.3
delta_h 14.3 kcal
Cl- + Ferric+3 = FerricCl+2
log_k 1.48
delta_h 5.6 kcal
2Cl- + Ferric+3 = FerricCl2+
log_k 2.13
3Cl- + Ferric+3 = FerricCl3
log_k 1.13
Ferric+3 + SulfateO4-2 = FerricSulfateO4+
log_k 4.04
delta_h 3.91 kcal
Ferric+3 + HSulfateO4- = FerricHSulfateO4+2
log_k 2.48
Ferric+3 + 2SulfateO4-2 = Ferric(SulfateO4)2-
log_k 5.38
delta_h 4.6 kcal
Ferric+3 + HPO4-2 = FerricHPO4+
log_k 5.43
delta_h 5.76 kcal
Ferric+3 + H2PO4- = FerricH2PO4+2
log_k 5.43
F- + Ferric+3 = FerricF+2
log_k 6.2
delta_h 2.7 kcal
2F- + Ferric+3 = FerricF2+
log_k 10.8
delta_h 4.8 kcal
3F- + Ferric+3 = FerricF3
log_k 14
delta_h 5.4 kcal
H2O + Manganous+2 = ManganousOH+ + H+
log_k -10.59
delta_h 14.4 kcal
Cl- + Manganous+2 = ManganousCl+
log_k 0.61
2Cl- + Manganous+2 = ManganousCl2
log_k 0.25
3Cl- + Manganous+2 = ManganousCl3-
log_k -0.31
Manganous+2 + CO3-2 = ManganousCO3
log_k 4.9
HCO3- + Manganous+2 = ManganousHCO3+
log_k 1.95
Manganous+2 + SulfateO4-2 = ManganousSulfateO4
log_k 2.25
delta_h 3.37 kcal
Manganous+2 + 2NitrateO3- = Manganous(NitrateO3)2
log_k 0.6
delta_h -0.396 kcal
F- + Manganous+2 = ManganousF+
log_k 0.84
Manganic+3 = Manganic+3
log_k 0
Al+3 + H2O = AlOH+2 + H+
log_k -5
delta_h 11.49 kcal
-analytical_expression -38.253 0 -656.27 14.327 0 0
Al+3 + 2H2O = Al(OH)2+ + 2H+
log_k -10.1
delta_h 26.9 kcal
-analytical_expression 88.5 0 -9391.6 -27.121 0 0
Al+3 + 3H2O = Al(OH)3 + 3H+
log_k -16.9
delta_h 39.89 kcal
-analytical_expression 226.374 0 -18247.8 -73.597 0 0
Al+3 + 4H2O = Al(OH)4- + 4H+
log_k -22.7
delta_h 42.3 kcal
-analytical_expression 51.578 0 -11168.9 -14.865 0 0
Al+3 + SulfateO4-2 = AlSulfateO4+
log_k 3.5
delta_h 2.29 kcal
Al+3 + 2SulfateO4-2 = Al(SulfateO4)2-
log_k 5
delta_h 3.11 kcal
Al+3 + HSulfateO4- = AlHSulfateO4+2
log_k 0.46
Al+3 + F- = AlF+2
log_k 7
delta_h 1.06 kcal
Al+3 + 2F- = AlF2+
log_k 12.7
delta_h 1.98 kcal
Al+3 + 3F- = AlF3
log_k 16.8
delta_h 2.16 kcal
Al+3 + 4F- = AlF4-
log_k 19.4
delta_h 2.2 kcal
Al+3 + 5F- = AlF5-2
log_k 20.6
delta_h 1.84 kcal
Al+3 + 6F- = AlF6-3
log_k 20.6
delta_h -1.67 kcal
H4SiO4 = H3SiO4- + H+
log_k -9.83
delta_h 6.12 kcal
-analytical_expression -302.3724 -0.050698 15669.69 108.18466 -1119669 0
H4SiO4 = H2SiO4-2 + 2H+
log_k -23
delta_h 17.6 kcal
-analytical_expression -294.0184 -0.07265 11204.49 108.18466 -1119669 0
6F- + 4H+ + H4SiO4 = SiF6-2 + 4H2O
log_k 30.18
delta_h -16.26 kcal
Ba+2 + H2O = BaOH+ + H+
log_k -13.47
Ba+2 + CO3-2 = BaCO3
log_k 2.71
delta_h 3.55 kcal
-analytical_expression 0.113 0.008721 0 0 0 0
Ba+2 + HCO3- = BaHCO3+
log_k 0.982
delta_h 5.56 kcal
-analytical_expression -3.0938 0.013669 0 0 0 0
Ba+2 + SulfateO4-2 = BaSulfateO4
log_k 2.7
H2O + Sr+2 = SrOH+ + H+
log_k -13.29
-gamma 5 0
H+ + Sr+2 + CO3-2 = SrHCO3+
log_k 11.509
delta_h 2.489 kcal
-analytical_expression 104.6391 0.04739549 -5151.79 -38.92561 563713.9 0
-gamma 5.4 0
Sr+2 + CO3-2 = SrCO3
log_k 2.81
delta_h 5.22 kcal
-analytical_expression -1.019 0.012826 0 0 0 0
Sr+2 + SulfateO4-2 = SrSulfateO4
log_k 2.29
delta_h 2.08 kcal
H2O + Li+ = LiOH + H+
log_k -13.64
Li+ + SulfateO4-2 = LiSulfateO4-
log_k 0.64
Cuprous+ = Cuprous+
log_k 0
-gamma 2.5 0
Cupric+2 + H2O = CupricOH+ + H+
log_k -8
-gamma 4 0
Cupric+2 + 2H2O = Cupric(OH)2 + 2H+
log_k -13.68
Cupric+2 + 3H2O = Cupric(OH)3- + 3H+
log_k -26.9
Cupric+2 + 4H2O = Cupric(OH)4-2 + 4H+
log_k -39.6
Cupric+2 + SulfateO4-2 = CupricSulfateO4
log_k 2.31
delta_h 1.22 kcal
H2O + Zn+2 = ZnOH+ + H+
log_k -8.96
delta_h 13.4 kcal
2H2O + Zn+2 = Zn(OH)2 + 2H+
log_k -16.9
3H2O + Zn+2 = Zn(OH)3- + 3H+
log_k -28.4
4H2O + Zn+2 = Zn(OH)4-2 + 4H+
log_k -41.2
Cl- + Zn+2 = ZnCl+
log_k 0.43
delta_h 7.79 kcal
2Cl- + Zn+2 = ZnCl2
log_k 0.45
delta_h 8.5 kcal
3Cl- + Zn+2 = ZnCl3-
log_k 0.5
delta_h 9.56 kcal
4Cl- + Zn+2 = ZnCl4-2
log_k 0.2
delta_h 10.96 kcal
Zn+2 + CO3-2 = ZnCO3
log_k 5.3
Zn+2 + 2CO3-2 = Zn(CO3)2-2
log_k 9.63
HCO3- + Zn+2 = ZnHCO3+
log_k 2.1
SulfateO4-2 + Zn+2 = ZnSulfateO4
log_k 2.37
delta_h 1.36 kcal
2SulfateO4-2 + Zn+2 = Zn(SulfateO4)2-2
log_k 3.28
Cd+2 + H2O = CdOH+ + H+
log_k -10.08
delta_h 13.1 kcal
Cd+2 + 2H2O = Cd(OH)2 + 2H+
log_k -20.35
Cd+2 + 3H2O = Cd(OH)3- + 3H+
log_k -33.3
Cd+2 + 4H2O = Cd(OH)4-2 + 4H+
log_k -47.35
Cd+2 + Cl- = CdCl+
log_k 1.98
delta_h 0.59 kcal
Cd+2 + 2Cl- = CdCl2
log_k 2.6
delta_h 1.24 kcal
Cd+2 + 3Cl- = CdCl3-
log_k 2.4
delta_h 3.9 kcal
Cd+2 + CO3-2 = CdCO3
log_k 2.9
Cd+2 + 2CO3-2 = Cd(CO3)2-2
log_k 6.4
Cd+2 + HCO3- = CdHCO3+
log_k 1.5
Cd+2 + SulfateO4-2 = CdSulfateO4
log_k 2.46
delta_h 1.08 kcal
Cd+2 + 2SulfateO4-2 = Cd(SulfateO4)2-2
log_k 3.5
H2O + Pb+2 = PbOH+ + H+
log_k -7.71
2H2O + Pb+2 = Pb(OH)2 + 2H+
log_k -17.12
3H2O + Pb+2 = Pb(OH)3- + 3H+
log_k -28.06
4H2O + Pb+2 = Pb(OH)4-2 + 4H+
log_k -39.7
H2O + 2Pb+2 = Pb2OH+3 + H+
log_k -6.36
Cl- + Pb+2 = PbCl+
log_k 1.6
delta_h 4.38 kcal
2Cl- + Pb+2 = PbCl2
log_k 1.8
delta_h 1.08 kcal
3Cl- + Pb+2 = PbCl3-
log_k 1.7
delta_h 2.17 kcal
4Cl- + Pb+2 = PbCl4-2
log_k 1.38
delta_h 3.53 kcal
Pb+2 + CO3-2 = PbCO3
log_k 7.24
Pb+2 + 2CO3-2 = Pb(CO3)2-2
log_k 10.64
HCO3- + Pb+2 = PbHCO3+
log_k 2.9
Pb+2 + SulfateO4-2 = PbSulfateO4
log_k 2.75
Pb+2 + 2SulfateO4-2 = Pb(SulfateO4)2-2
log_k 3.47
NitrateO3- + Pb+2 = PbNitrateO3+
log_k 1.17
PHASES
redoxCalcite
CaCO3 = Ca+2 + CO3-2
log_k -8.48
delta_h -2.297 kcal
-analytical_expression -171.9065 -0.077993 2839.319 71.595 0 0
redoxAragonite
CaCO3 = Ca+2 + CO3-2
log_k -8.336
delta_h -2.589 kcal
-analytical_expression -171.9773 -0.077993 2903.293 71.595 0 0
redoxDolomite
CaMg(CO3)2 = Ca+2 + Mg+2 + 2CO3-2
log_k -17.09
delta_h -9.436 kcal
redoxSiderite
FerrousCO3 = Ferrous+2 + CO3-2
log_k -10.89
delta_h -2.48 kcal
redoxRhodochrosite
ManganousCO3 = Manganous+2 + CO3-2
log_k -11.13
delta_h -1.43 kcal
redoxStrontianite
SrCO3 = Sr+2 + CO3-2
log_k -9.271
delta_h -0.4 kcal
-analytical_expression 155.0305 0 -7239.594 -56.58638 0 0
redoxWitherite
BaCO3 = Ba+2 + CO3-2
log_k -8.562
delta_h 0.703 kcal
-analytical_expression 607.642 0.121098 -20011.25 -236.4948 0 0
redoxGypsum
CaSulfateO4:2H2O = Ca+2 + 2H2O + SulfateO4-2
log_k -4.58
delta_h -0.109 kcal
-analytical_expression 68.2401 0 -3221.51 -25.0627 0 0
redoxAnhydrite
CaSulfateO4 = Ca+2 + SulfateO4-2
log_k -4.36
delta_h -1.71 kcal
-analytical_expression 197.52 0 -8669.8 -69.835 0 0
redoxCelestite
SrSulfateO4 = Sr+2 + SulfateO4-2
log_k -6.63
delta_h -1.037 kcal
-analytical_expression -14805.9622 -2.4660924 756968.533 5436.3588 -40553604 0
redoxBarite
BaSulfateO4 = Ba+2 + SulfateO4-2
log_k -9.97
delta_h 6.35 kcal
-analytical_expression 136.035 0 -7680.41 -48.595 0 0
Hydroxyapatite
Ca5(PO4)3OH + 4H+ = 5Ca+2 + H2O + 3HPO4-2
log_k -3.421
delta_h -36.155 kcal
Fluorite
CaF2 = Ca+2 + 2F-
log_k -10.6
delta_h 4.69 kcal
-analytical_expression 66.348 0 -4298.2 -25.271 0 0
SiO2(a)
SiO2 + 2H2O = H4SiO4
log_k -2.71
delta_h 3.34 kcal
-analytical_expression -0.26 0 -731 0 0 0
Chalcedony
SiO2 + 2H2O = H4SiO4
log_k -3.55
delta_h 4.72 kcal
-analytical_expression -0.09 0 -1032 0 0 0
Quartz
SiO2 + 2H2O = H4SiO4
log_k -3.98
delta_h 5.99 kcal
-analytical_expression 0.41 0 -1309 0 0 0
Gibbsite
Al(OH)3 + 3H+ = Al+3 + 3H2O
log_k 8.11
delta_h -22.8 kcal
Al(OH)3(a)
Al(OH)3 + 3H+ = Al+3 + 3H2O
log_k 10.8
delta_h -26.5 kcal
Kaolinite
Al2Si2O5(OH)4 + 6H+ = 2Al+3 + H2O + 2H4SiO4
log_k 7.435
delta_h -35.3 kcal
Albite
NaAlSi3O8 + 8H2O = Al(OH)4- + 3H4SiO4 + Na+
log_k -18.002
delta_h 25.896 kcal
Anorthite
CaAl2Si2O8 + 8H2O = 2Al(OH)4- + Ca+2 + 2H4SiO4
log_k -19.714
delta_h 11.58 kcal
K-feldspar
KAlSi3O8 + 8H2O = Al(OH)4- + 3H4SiO4 + K+
log_k -20.573
delta_h 30.82 kcal
K-mica
KAl3Si3O10(OH)2 + 10H+ = 3Al+3 + 3H4SiO4 + K+
log_k 12.703
delta_h -59.376 kcal
Chlorite(14A)
Mg5Al2Si3O10(OH)8 + 16H+ = 2Al+3 + 6H2O + 3H4SiO4 + 5Mg+2
log_k 68.38
delta_h -151.494 kcal
Ca-Montmorillonite
Ca0.165Al2.33Si3.67O10(OH)2 + 12H2O = 2.33Al(OH)4- + 0.165Ca+2 + 2H+ + 3.67H4SiO4
log_k -45.027
delta_h 58.373 kcal
Talc
Mg3Si4O10(OH)2 + 6H+ + 4H2O = 4H4SiO4 + 3Mg+2
log_k 21.399
delta_h -46.352 kcal
Illite
K0.6Mg0.25Al2.3Si3.5O10(OH)2 + 11.2H2O = 2.3Al(OH)4- + 1.2H+ + 3.5H4SiO4 + 0.6K+ + 0.25Mg+2
log_k -40.267
delta_h 54.684 kcal
Chrysotile
Mg3Si2O5(OH)4 + 6H+ = H2O + 2H4SiO4 + 3Mg+2
log_k 32.2
delta_h -46.8 kcal
-analytical_expression 13.248 0 10217.1 -6.1894 0 0
Sepiolite
Mg2Si3O7.5OH:3H2O + 4H+ + 0.5H2O = 3H4SiO4 + 2Mg+2
log_k 15.76
delta_h -10.7 kcal
Sepiolite(d)
Mg2Si3O7.5OH:3H2O + 4H+ + 0.5H2O = 3H4SiO4 + 2Mg+2
log_k 18.66
redoxHematite
Ferric2O3 + 6H+ = 2Ferric+3 + 3H2O
log_k -4.008
delta_h -30.845 kcal
redoxGoethite
FerricOOH + 3H+ = Ferric+3 + 2H2O
log_k -1
delta_h -14.48 kcal
redoxFe(OH)3(a)
Ferric(OH)3 + 3H+ = Ferric+3 + 3H2O
log_k 4.891
redoxPyrite
FerrousSulfide2 + 2H+ + 2e- = Ferrous+2 + 2HSulfide-
log_k -18.479
delta_h 11.3 kcal
redoxFeS(ppt)
FerrousSulfide + H+ = Ferrous+2 + HSulfide-
log_k -3.915
redoxMackinawite
FerrousSulfide + H+ = Ferrous+2 + HSulfide-
log_k -4.648
redoxSulfur
Sulfide + 2H+ + 2e- = H2Sulfide
log_k 4.882
delta_h -9.5 kcal
redoxVivianite
Ferrous3(PO4)2:8H2O = 3Ferrous+2 + 8H2O + 2PO4-3
log_k -36
redoxHausmannite
ManganousManganic2O4 + 8H+ = 4H2O + 2Manganic+3 + Manganous+2
log_k 10.01
redoxManganite
ManganicOOH + 3H+ = 2H2O + Manganic+3
log_k -0.17
redoxPyrochroite
Manganous(OH)2 + 2H+ = 2H2O + Manganous+2
log_k 15.2
Halite
NaCl = Cl- + Na+
log_k 1.582
delta_h 0.918 kcal
redoxCO2(g)
CO2 = CO2
log_k -1.468
delta_h -4.776 kcal
-analytical_expression 108.3865 0.01985076 -6919.53 -40.45154 669365 0
redoxO2(g)
Ozero2 = Ozero2
log_k -2.8983
-analytical_expression -7.5001 0.0078981 0 0 200270 0
H2(g)
H2 = H2
log_k -3.15
delta_h -1.759 kcal
redoxH2(g)
Hzero2 = Hzero2
log_k -3.15
delta_h -1.759 kcal
H2O(g)
H2O = H2O
log_k 1.51
delta_h -44.03 kJ
redoxN2(g)
Nzero2 = Nzero2
log_k -3.26
delta_h -1.358 kcal
redoxH2S(g)
H2Sulfide = H2Sulfide
log_k -0.997
delta_h -4.57 kcal
redoxCH4(g)
MethaneH4 = MethaneH4
log_k -2.86
delta_h -3.373 kcal
redoxNH3(g)
AmmH3 = AmmH3
log_k 1.77
delta_h -8.17 kcal
redoxMelanterite
FerrousSulfateO4:7H2O = Ferrous+2 + 7H2O + SulfateO4-2
log_k -2.209
delta_h 4.91 kcal
-analytical_expression 1.447 -0.004153 0 0 -214949 0
redoxAlunite
KAl3(SulfateO4)2(OH)6 + 6H+ = 3Al+3 + 6H2O + K+ + 2SulfateO4-2
log_k -1.4
delta_h -50.25 kcal
redoxJarosite-K
KFerric3(SulfateO4)2(OH)6 + 6H+ = 3Ferric+3 + 6H2O + K+ + 2SulfateO4-2
log_k -9.21
delta_h -31.28 kcal
Zn(OH)2(e)
Zn(OH)2 + 2H+ = 2H2O + Zn+2
log_k 11.5
redoxSmithsonite
ZnCO3 = Zn+2 + CO3-2
log_k -10
delta_h -4.36 kcal
redoxSphalerite
ZnSulfide + H+ = HSulfide- + Zn+2
log_k -11.618
delta_h 8.25 kcal
Willemite
Zn2SiO4 + 4H+ = H4SiO4 + 2Zn+2
log_k 15.33
delta_h -33.37 kcal
Cd(OH)2
Cd(OH)2 + 2H+ = Cd+2 + 2H2O
log_k 13.65
redoxOtavite
CdCO3 = Cd+2 + CO3-2
log_k -12.1
delta_h -0.019 kcal
CdSiO3
CdSiO3 + 2H+ + H2O = Cd+2 + H4SiO4
log_k 9.06
delta_h -16.63 kcal
redoxCdSO4
CdSulfateO4 = Cd+2 + SulfateO4-2
log_k -0.1
delta_h -14.74 kcal
redoxCerrusite
PbCO3 = Pb+2 + CO3-2
log_k -13.13
delta_h 4.86 kcal
redoxAnglesite
PbSulfateO4 = Pb+2 + SulfateO4-2
log_k -7.79
delta_h 2.15 kcal
Pb(OH)2
Pb(OH)2 + 2H+ = 2H2O + Pb+2
log_k 8.15
delta_h -13.99 kcal
EXCHANGE_MASTER_SPECIES
X X-
EXCHANGE_SPECIES
X- = X-
log_k 0
Na+ + X- = NaX
log_k 0
-gamma 4 0.075
K+ + X- = KX
log_k 0.7
delta_h -4.3 kJ
-gamma 3.5 0.015
Li+ + X- = LiX
log_k -0.08
delta_h 1.4 kJ
-gamma 6 0
AmmH4+ + X- = AmmH4X
log_k 0.6
delta_h -2.4 kJ
-gamma 2.5 0
Ca+2 + 2X- = CaX2
log_k 0.8
delta_h 7.2 kJ
-gamma 5 0.165
Mg+2 + 2X- = MgX2
log_k 0.6
delta_h 7.4 kJ
-gamma 5.5 0.2
Sr+2 + 2X- = SrX2
log_k 0.91
delta_h 5.5 kJ
-gamma 5.26 0.121
Ba+2 + 2X- = BaX2
log_k 0.91
delta_h 4.5 kJ
-gamma 5 0
Manganous+2 + 2X- = ManganousX2
log_k 0.52
-gamma 6 0
Ferrous+2 + 2X- = FerrousX2
log_k 0.44
-gamma 6 0
Cupric+2 + 2X- = CupricX2
log_k 0.6
-gamma 6 0
2X- + Zn+2 = ZnX2
log_k 0.8
-gamma 5 0
Cd+2 + 2X- = CdX2
log_k 0.8
-davies
Pb+2 + 2X- = PbX2
log_k 1.05
-davies
Al+3 + 3X- = AlX3
log_k 0.41
-gamma 9 0
AlOH+2 + 2X- = AlOHX2
log_k 0.89
-davies
SURFACE_MASTER_SPECIES
Hfo_s Hfo_sOH
Hfo_w Hfo_wOH
SURFACE_SPECIES
Hfo_sOH = Hfo_sOH
log_k 0
H+ + Hfo_sOH = Hfo_sOH2+
log_k 7.29
Hfo_sOH = Hfo_sO- + H+
log_k -8.93
Hfo_wOH = Hfo_wOH
log_k 0
H+ + Hfo_wOH = Hfo_wOH2+
log_k 7.29
Hfo_wOH = Hfo_wO- + H+
log_k -8.93
Ca+2 + Hfo_sOH = Hfo_sOHCa+2
log_k 4.97
Ca+2 + Hfo_wOH = Hfo_wOCa+ + H+
log_k -5.85
Hfo_sOH + Sr+2 = Hfo_sOHSr+2
log_k 5.01
Hfo_wOH + Sr+2 = Hfo_wOSr+ + H+
log_k -6.58
H2O + Hfo_wOH + Sr+2 = Hfo_wOSrOH + 2H+
log_k -17.6
Ba+2 + Hfo_sOH = Hfo_sOHBa+2
log_k 5.46
Ba+2 + Hfo_wOH = Hfo_wOBa+ + H+
log_k -7.2
Cd+2 + Hfo_sOH = Hfo_sOCd+ + H+
log_k 0.47
Cd+2 + Hfo_wOH = Hfo_wOCd+ + H+
log_k -2.91
Hfo_sOH + Zn+2 = Hfo_sOZn+ + H+
log_k 0.99
Hfo_wOH + Zn+2 = Hfo_wOZn+ + H+
log_k -1.99
Cupric+2 + Hfo_sOH = Hfo_sOCupric+ + H+
log_k 2.89
Cupric+2 + Hfo_wOH = Hfo_wOCupric+ + H+
log_k 0.6
Hfo_sOH + Pb+2 = Hfo_sOPb+ + H+
log_k 4.65
Hfo_wOH + Pb+2 = Hfo_wOPb+ + H+
log_k 0.3
Hfo_wOH + Mg+2 = Hfo_wOMg+ + H+
log_k -4.6
Hfo_sOH + Manganous+2 = Hfo_sOManganous+ + H+
log_k -0.4
Hfo_wOH + Manganous+2 = Hfo_wOManganous+ + H+
log_k -3.5
Ferrous+2 + Hfo_sOH = Hfo_sOFerrous+ + H+
log_k -0.95
Ferrous+2 + Hfo_wOH = Hfo_wOFerrous+ + H+
log_k -2.98
Ferrous+2 + H2O + Hfo_wOH = Hfo_wOFerrousOH + 2H+
log_k -11.55
3H+ + Hfo_wOH + PO4-3 = Hfo_wH2PO4 + H2O
log_k 31.29
2H+ + Hfo_wOH + PO4-3 = Hfo_wHPO4- + H2O
log_k 25.39
H+ + Hfo_wOH + PO4-3 = Hfo_wPO4-2 + H2O
log_k 17.72
H3BO3 + Hfo_wOH = Hfo_wH2BO3 + H2O
log_k 0.62
H+ + Hfo_wOH + SulfateO4-2 = Hfo_wSulfateO4- + H2O
log_k 7.78
Hfo_wOH + SulfateO4-2 = Hfo_wOHSulfateO4-2
log_k 0.79
F- + H+ + Hfo_wOH = Hfo_wF + H2O
log_k 8.7
F- + Hfo_wOH = Hfo_wOHF-
log_k 1.6
END
--- End code ---
GeeqC:
It seems that I caused a confusion. I did not mean to set the equilibrium constants (log k) to zero. With "k" I meant the kinetic rate constant: Rate = k * [Conc.]. Some reactions show more complex kinetics. AOM is a good example:
CH4 + SO4-2 <--> HCO3- + HS- + H2O
Many studies have demonstrated that this reaction follows a Monod-type kinetic:
R(AOM) = [CH4] * k(AOM) * [SO4-2]/(Ks + [SO4-2])
This rate is coupled to the reaction transport model as a source/sink term in the transport equation. It is then a problem that Phreeqc supersedes the kinetic rate calculation by setting the reaction to equilibrium. In the example of AOM it means the reaction runs almost to completeness.
I do not understand the logics of Phreeqc here. If running a simple input file, Phreeqc does the right thing: it runs the speciation without changing the redox states of the totals. The same should be possible when running the workers in PhreeqcRM.
I could imagine that many users are not even aware of this problem. As a workaround it may be possible to define a kinetics data block for each redox couple and set the rate constant to zero (that's what I meant earlier).
dlparkhurst:
The simplest way to handle redox reactions is to add the oxidant or reductant kinetically. If you want to consider AOM, I would use Mtg, which is defined in phreeqc.dat as an unreactive form of methane, to define a pool of methane, gas and/or dissolved. Then you can kinetically convert Mtg to CH4. The CH4 will reduce sulfate if that is thermodynamically favored. It will definitely reduce O2, NO3-, Fe(3), and others, depending on the most favored electron acceptor. The rate of the reaction is controlled simply by the rate of the Mtg to CH4 conversion. You do not have to consider kinetic reactions among all the other redox couples; they all occur at thermodynamic equilibrium.
You can get as complicated as you want splitting redox states into separate elements and having them react kinetically. The database I posted will have no redox reactions without specific kinetic reactions. But I ask you if you kinetically react methane with sulfate, when does the reaction stop, and what happens to As, Fe, or Se(-2) during these reactions? Are you going to oxidize each of them kinetically and keep thermodynamic consistency?
dlparkhurst:
Here is the idea; you would replace REACTION with KINETICS for the kinetic transformation of Mtg to CH4 for a kinetic or transport model.
--- Code: ---SOLUTION
Na 2
S(6) 1
REACTION
CH4 1
0.003 in 10
USER_GRAPH 1
-headings rxn S(6) C(4) C(-4) S(-2)
-axis_titles "CH4 added to solution, moles" "Molality" ""
-axis_scale y_axis auto auto auto auto log
-initial_solutions false
-connect_simulations true
-plot_concentration_vs x
-start
10 GRAPH_X RXN
20 GRAPH_Y TOT("S(6)"), TOT("C(4)"), TOT("C(-4)"), TOT("S(-2)")
-end
-active true
--- End code ---
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