How to change the pH of Surface problem with mixing by steps from5 to 11

[MACAHarding]

Hello,

I also need to graph Co totals as a function of pH change. The following code gives me 5 and 11 for pH.

Code: [Select]

TITLE Problem#1: Modeling Competitive Adsorption. Arsenic Adsorption Problem

SOULTION_SPECIES
CrO4-2 + 6H+ + 3e- = Cr(OH)2+ + 2H2O
log_k 100. #67.376
Cu+2 + e- = Cu+
log_k -100. #2.69
END
     
PHASES
Ferrihydrite
Fe(OH)3 + 3H+ = Fe+3 + 3H2O
log_k 3.191
delta_h -73.374 kJ
Fix_H+
H+ = H+
log_k 0

END 


SOLUTION 1 #Backgound water
    temp      25
    pH        7.04
    pe        4 Ferrihydrite 0
    redox     pe
    units     mg/kgw
    density   1
    As        0.000967
    B         0.0468
    Ba        0.037
    C(4)      142
    Ca        31.7
    Cd        5.41e-005
    Cl        15.8
    Co        0.000138
    Cr        0.0007797
    Cu        0.00284
    F         0.194
    Fe        0.0792
    K         2.51
    Li        7.59e-3
    Mg        8.9
    Mn        0.012
    Mo        0.000753
    Na        25
    Ni        0.0007778
    Pb        0.000207
    S         18.6
    Sb        7.47e-005
    Se        0.000557
    Sr        0.219
    V         0.0012
    Zn        0.00761
    -water    1 # kg

EQUILIBRIUM_PHASES 1
    Ferrihydrite 0 0.01
   

SURFACE 1
    -equilibrate with solution 1
    Hfo_wOH Ferrihydrite    equilibrium_phase 0.2    600
    Hfo_sOH Ferrihydrite    equilibrium_phase 0.0025


SAVE Solution 1
SAVE Equilibrium_phases 1
SAVE Surface 1

END

USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -5 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -6 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -7 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -8 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -9 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -10 Ca(OH)2; USE Surface 1;
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -11 Ca(OH)2; USE Surface 1;

SOLUTION 2 #leachate
    temp      25
    pH        5
    pe        4 Ferrihydrite 0
    redox     pe
    units     mg/kgw
    density   1
    As        0.0723
    B         1.73
    Ba        0.0631
    C(4)      19.3
    Ca        117
    Cd        0.00209
    Cl        16.1
    Co        0.00161
    Cr        0.00144
    Cu        0.002654
    F         0.178
    Fe        0.457
    K         15.1
    Li        0.17
    Mg        2.92
    Mn        0.109
    Mo        0.35
    Na        18.1
    Ni        0.0134
    Pb        0.000934
    S         333
    Sb        0.00453
    Se        0.00784
    Sr        1.02
    V         0.0305
    Zn        0.018
    -water    1 # kg

MIX 1
    1    0
    2    1

SELECTED_OUTPUT 1
-file P1.AsAdsorptionProblem.csv
-reset false
      -reaction   false
-pH true
-totals Co

END



[dlparkhurst]

Code: [Select]

TITLE Problem#1: Modeling Competitive Adsorption. Arsenic Adsorption Problem

SOULTION_SPECIES
CrO4-2 + 6H+ + 3e- = Cr(OH)2+ + 2H2O
log_k 100. #67.376
Cu+2 + e- = Cu+
log_k -100. #2.69
END
     
PHASES
Ferrihydrite
Fe(OH)3 + 3H+ = Fe+3 + 3H2O
log_k 3.191
delta_h -73.374 kJ
Fix_H+
H+ = H+
log_k 0

END


SOLUTION 1 #Backgound water
    temp      25
    pH        7.04
    pe        4 Ferrihydrite 0
    redox     pe
    units     mg/kgw
    density   1
    As        0.000967
    B         0.0468
    Ba        0.037
    C(4)      142
    Ca        31.7
    Cd        5.41e-005
    Cl        15.8
    Co        0.000138
    Cr        0.0007797
    Cu        0.00284
    F         0.194
    Fe        0.0792
    K         2.51
    Li        7.59e-3
    Mg        8.9
    Mn        0.012
    Mo        0.000753
    Na        25
    Ni        0.0007778
    Pb        0.000207
    S         18.6
    Sb        7.47e-005
    Se        0.000557
    Sr        0.219
    V         0.0012
    Zn        0.00761
    -water    1 # kg

EQUILIBRIUM_PHASES 1
    Ferrihydrite 0 0.01
   

SURFACE 1
    -equilibrate with solution 1
    Hfo_wOH Ferrihydrite    equilibrium_phase 0.2    600
    Hfo_sOH Ferrihydrite    equilibrium_phase 0.0025


SAVE Solution 1
SAVE Equilibrium_phases 1
SAVE Surface 1

END
USER_GRAPH
10 GRAPH_X -LA("H+")
20 GRAPH_Y TOT("Co")
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -5 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -6 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -7 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -8 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -9 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -10 Ca(OH)2; USE Surface 1; END
USE Solution 1; Equilibrium_phases 1; Ferrihydrite 0 0.1; Fix_H+ -11 Ca(OH)2; USE Surface 1; END

END