[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Alkaline Solutions and CO2

Here's a file that should help. It adds CO2 to your solution until calcite
is saturated. It also adds NaOH to maintain the pH at 10. If you add enough
CO2 to get close to 1 atmosphere pCO2 (as it looks like you intended from
your input file), you will have a very concentrated solution of NaHCO3 and
the program could fail to converge. . In this run, it takes about 25
micromoles of CO2 to get to calcite saturation, but you need to add 100
micromoles of NaOH and log(pCO2) is -7. It helps to add the oxygen to
define the redox condition more robustly.


SOLUTION 1 Nutrient Solution, pH 10, No CO2
temp 30
pH 10
pe 4
redox pe
units umol/kgw
density 1
B 0.16
Ca 700
Cl 256 charge
K 133
Mg 133
Na 0
N(-3) 47
N(5) 423
P 3
Zn 0.1
Cu 0.04
Fe 5
Mn 0.2
S(6) 500
C 0.00001
-water 1 # kg

# Fix pO2 at .1 atm
O2(g) -1
# Add CO2(g) until calcite saturation
Calcite  0.0  CO2(g) 10
# Add NaOH to pH 10
FIX_H+  -10. NaOH 10

# Fake phase used to fix pH
      H+ = H+
      logK 0

David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

Project Home Page
Complete Water Resources Division Software
USGS Home Page
Water Resources Division Home Page
NRP Home Page
Help Page
USGS Privacy Statement       

Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 

The URL of this page is: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail/msg00242.html
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 4138 since Jan 22, 1998.