Hi,
I'm new to PHREEQC (usually use Geochemist's Workbench but our PC has died)
and could use some help formulating an aqueous speciation problem...
I am trying to produce pH and species concentration data (to eventually
construct a speciation diagram) for Cu++ in pure water and Cu++ in 0.1 M
NaNO3. I require both calculations to be performed with the suppression of
CuO (s) and Cu(OH)2 (s) and then would like to repeat the calculations with
the suppression of just CuO (s) (so letting Cu(OH)2 (s) precipitate).
I have amended the llnl database to include the following aqueous species
Cu+2 + H2O = CuOH+ + H+
log_k -8.2
Cu+2 + 2 H2O = Cu(OH)2 + 2 H+
log_k -17.5
2Cu+2 + 2 H2O = Cu2(OH)2+2 + 2 H+
log_k -10.59
Cu+2 + 3 H2O = Cu(OH)3- + 3 H+
log_k -27.8
Cu+2 + 4 H2O = Cu(OH)4-2 + 4 H+
log_k -39.6
and solids
Cu(OH)2(s)
Cu(OH)2 + 2H+ = Cu+2 + 2H2O
log_k = 9.12
and i have removed Cu+ (and all references to it).
I have successfully produced two speciation output files in pure water (see
attached) - at pH 6 and 8 - to illustrate the increasing extent of
Cu(OH)2(s) precipitation with pH (seen as a change in the SI for Cu(OH)2
(s))....do i now assume that the Cu++ deficit (ie: the difference between
the total Cu++ in the system and the total Cu++ aqueous species as listed in
the output file) is the mol/L of precipitate?
So in summary! Could you help me produce
a) speciation of Cu++ in pure water; CuO(s) and Cu(OH)2(s) suppressed
b) speciation of Cu++ in 0.1 M NaNO3; CuO(s) and Cu(OH)2(s) suppressed
c) speciation of Cu++ in pure water; CuO(s) suppressed - so eventual
speciation diagram actually showing the fraction of Cu(OH)2(s) present with
pH
d) speciation of Cu++ in 0.1 M NaNO3; CuO(s) suppressed - so eventual
speciation diagram actually showing the fraction of Cu(OH)2(s) present with
pH
Thank you in advance for your help
Caroline Peacock
*****************************************
Caroline L. Peacock
Environmental Geochemistry
Department of Earth Sciences
University of Bristol
Wills Memorial Building, Queens Road,
Clifton, Bristol, BS8 IRJ, UK.
Tel: +44 117 9545246
Fax: +44 117 9253385
http://mineral.gly.bris.ac.uk/
*****************************************
Input file: CuS1
Output file: CuS1pH6s.out
Database file: cocosolid.dat
------------------
Reading data base.
------------------
LLNL_AQUEOUS_MODEL_PARAMETERS
SOLUTION_MASTER_SPECIES
SOLUTION_SPECIES
PHASES
EXCHANGE_MASTER_SPECIES
EXCHANGE_SPECIES
SURFACE_MASTER_SPECIES
SURFACE_SPECIES
RATES
END
------------------------------------
Reading input data for simulation 1.
------------------------------------
TITLE Speciating Copper in water
SOLUTION 1
units ppm
pH 6.00
temp 25.0
Cu 25.00
SAVE SOLUTION 1
END
-----
TITLE
-----
Speciating Copper in water
-------------------------------------------
Beginning of initial solution calculations.
-------------------------------------------
Initial solution 1.
-----------------------------Solution composition------------------------------
Elements Molality Moles
Cu 3.934e-04 3.934e-04
----------------------------Description of solution----------------------------
pH = 6.000
pe = 4.000
Activity of water = 1.000
Ionic strength = 7.550e-04
Mass of water (kg) = 1.000e+00
Total alkalinity (eq/kg) = 2.262e-05
Total carbon (mol/kg) = 0.000e+00
Total CO2 (mol/kg) = 0.000e+00
Temperature (deg C) = 25.000
Electrical balance (eq) = 7.642e-04
Percent error, 100*(Cat-|An|)/(Cat+|An|) = 100.00
Iterations = 4
Total H = 1.110507e+02
Total O = 5.552535e+01
----------------------------Distribution of species----------------------------
Log Log Log
Species Molality Activity Molality Activity Gamma
H+ 1.030e-06 1.000e-06 -5.987 -6.000 -0.013
OH- 9.941e-09 9.635e-09 -8.003 -8.016 -0.014
H2O 5.553e+01 1.000e+00 -0.000 -0.000 0.000
Cu(2) 3.934e-04
Cu+2 3.698e-04 3.271e-04 -3.432 -3.485 -0.053
CuOH+ 1.741e-05 1.687e-05 -4.759 -4.773 -0.014
Cu2(OH)2+2 3.114e-06 2.750e-06 -5.507 -5.561 -0.054
Cu(OH)2 1.034e-09 1.034e-09 -8.985 -8.985 0.000
Cu(OH)3- 5.348e-14 5.184e-14 -13.272 -13.285 -0.014
CuO2-2 1.316e-19 1.161e-19 -18.881 -18.935 -0.054
Cu(OH)4-2 9.304e-20 8.216e-20 -19.031 -19.085 -0.054
H(0) 1.587e-23
H2 7.934e-24 7.935e-24 -23.101 -23.100 0.000
O(0) 0.000e+00
O2 0.000e+00 0.000e+00 -45.995 -45.995 0.000
------------------------------Saturation indices-------------------------------
Phase SI log IAP log KT
Cu 0.02 -11.49 -11.50 Cu
Cu(g) -52.14 -11.49 40.66 Cu
Cu(OH)2(s) -0.61 8.51 9.12 Cu(OH)2
H2(g) -20.00 -20.00 -0.00 H2
H2O(g) -1.59 -0.00 1.59 H2O
Ice -0.14 -0.00 0.14 H2O
O2(g) -43.10 40.00 83.10 O2
------------------
End of simulation.
------------------
------------------------------------
Reading input data for simulation 2.
------------------------------------
-----------
End of run.
-----------
Input file: CuS1
Output file: CuS1pH8s.out
Database file: cocosolid.dat
------------------
Reading data base.
------------------
LLNL_AQUEOUS_MODEL_PARAMETERS
SOLUTION_MASTER_SPECIES
SOLUTION_SPECIES
PHASES
EXCHANGE_MASTER_SPECIES
EXCHANGE_SPECIES
SURFACE_MASTER_SPECIES
SURFACE_SPECIES
RATES
END
------------------------------------
Reading input data for simulation 1.
------------------------------------
TITLE Speciating Copper in water
SOLUTION 1
temp 25.0
units ppm
Cu 25.00
pH 8
PHASES
Fix_H+
H+ = H+
log_k 0.0
SAVE Solution 1
END
-----
TITLE
-----
Speciating Copper in water
-------------------------------------------
Beginning of initial solution calculations.
-------------------------------------------
Initial solution 1.
-----------------------------Solution composition------------------------------
Elements Molality Moles
Cu 3.934e-04 3.934e-04
----------------------------Description of solution----------------------------
pH = 8.000
pe = 4.000
Activity of water = 1.000
Ionic strength = 3.602e-04
Mass of water (kg) = 1.000e+00
Total alkalinity (eq/kg) = 3.718e-04
Total carbon (mol/kg) = 0.000e+00
Total CO2 (mol/kg) = 0.000e+00
Temperature (deg C) = 25.000
Electrical balance (eq) = 4.151e-04
Percent error, 100*(Cat-|An|)/(Cat+|An|) = 99.53
Iterations = 9
Total H = 1.110510e+02
Total O = 5.552570e+01
----------------------------Distribution of species----------------------------
Log Log Log
Species Molality Activity Molality Activity Gamma
OH- 9.847e-07 9.635e-07 -6.007 -6.016 -0.009
H+ 1.021e-08 1.000e-08 -7.991 -8.000 -0.009
H2O 5.553e+01 1.000e+00 -0.000 -0.000 0.000
Cu(2) 3.934e-04
Cu2(OH)2+2 1.283e-04 1.176e-04 -3.892 -3.929 -0.038
CuOH+ 1.128e-04 1.104e-04 -3.948 -3.957 -0.009
Cu+2 2.332e-05 2.139e-05 -4.632 -4.670 -0.037
Cu(OH)2 6.765e-07 6.765e-07 -6.170 -6.170 0.000
Cu(OH)3- 3.465e-09 3.391e-09 -8.460 -8.470 -0.009
CuO2-2 8.288e-13 7.596e-13 -12.082 -12.119 -0.038
Cu(OH)4-2 5.861e-13 5.374e-13 -12.232 -12.270 -0.038
H(0) 1.587e-27
H2 7.934e-28 7.935e-28 -27.100 -27.100 0.000
O(0) 2.023e-38
O2 1.011e-38 1.011e-38 -37.995 -37.995 0.000
------------------------------Saturation indices-------------------------------
Phase SI log IAP log KT
Cu -1.17 -12.67 -11.50 Cu
Cu(g) -53.33 -12.67 40.66 Cu
Cu(OH)2(s) 2.21 11.33 9.12 Cu(OH)2
Fix_H+ -8.00 -8.00 0.00 H+
H2(g) -24.00 -24.00 -0.00 H2
H2O(g) -1.59 -0.00 1.59 H2O
Ice -0.14 -0.00 0.14 H2O
O2(g) -35.10 48.00 83.10 O2
------------------
End of simulation.
------------------
------------------------------------
Reading input data for simulation 2.
------------------------------------
-----------
End of run.
-----------
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