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Adding protons to the solution
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Topic: Adding protons to the solution (Read 1232 times)
PhreeqCuser2024
Contributor
Posts: 2
Adding protons to the solution
«
on:
February 02, 2016, 07:36:21 AM »
Dear all,
I have a question regarding PhreeqC input and protons in the solution. I wish to calculate pH and ion speciation as a function of solution composition. As base of the solution I want to use CaCl2, Na2CO3 and NaHCO3. Later I want to add other ions such as ammonia as well.
By using different combinations of Na2CO3 and NaHCO3 you should get a different pH. However, I am unsure how to put this in the input file. Take for example the following three solutions:
units are in mol/kgw
A) 0.1 CaCl2, 0.1 Na2CO3, 0 NaHCO3 => in ions meaning 0.2 Cl-, 0.2 Na+, 0.1 CO3-2 and 0.1 Ca+2, with 0 H+ added to the solution
B) 0.1 CaCl2, 0.05 Na2CO3, 0.05 NaHCO3 => in ions meaning 0.2 Cl-, 0.15 Na+, 0.1 CO3-2 and 0.1 Ca+2, with 0.05 H+ added to the solution
C) 0.1 CaCl2, 0 Na2CO3, 0.1 NaHCO3 => in ions meaning 0.2 Cl-, 0.1 Na+, 0.1 CO3-2 and 0.1 Ca+2, with 0.1 H+ added to the solution
The question is now how to add the protons to the following input file:
---
solution_s
-temp 25
-pH 7 charge
-units mol/kgw
Ca C(4) Na Cl
0.1 0.1 0.2 0.2
0.1 0.1 0.15 0.2
0.1 0.1 0.1 0.2
---
I am aware that the calculation error will accumulate in the calculate pH value, nevertheless I am very much interested in the prediction of PhreeqC.
Please note that later I will introduce sources of alkalinity other than carbonate to the solution. Therefore 'alkalinity as carbonate' is not really an option.
Any help is much appreciated,
Luke
«
Last Edit: February 03, 2016, 07:10:20 AM by PhreeqCuser2024
»
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dlparkhurst
Top Contributor
Posts: 1270
Re: Addaing protons to the solution
«
Reply #1 on:
February 02, 2016, 08:29:37 AM »
Here are three ways to create solution "B". The others can be made similarly.
SOLUTION 1
temp 25
pH 7 charge
pe 4
redox pe
units mol/kgw
density 1
C(4) 0.1
Ca 0.1
Cl 0.2
Na 0.15
-water 1 # kg
END
SOLUTION_SPREAD
-units mol/kgw
C(4) Ca Cl Na pH
charge
0.1 0.1 0.2 0.15 7
END
SOLUTION 2
END
USE solution 2
REACTION 1
CaCl2 0.1
Na2CO3 0.05
NaHCO3 0.05
1 moles
END
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PhreeqCuser2024
Contributor
Posts: 2
Re: Adding protons to the solution
«
Reply #2 on:
February 03, 2016, 07:10:56 AM »
It works perfectly, thank you very much!
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Adding protons to the solution