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. David 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 EQUILIBRIUM_PHASES 1 # 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 PHASES # Fake phase used to fix pH FIX_H+ H+ = H+ logK 0 END David Parkhurst (dlpark@xxxxxxxx) U.S. Geological Survey Box 25046, MS 413 Denver Federal Center Denver, CO 80225
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:
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 2809 since Jan 22, 1998.