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

Re: selectivity coefficients




It is not necessary to bias the log K by 20 in PHREEQC. This was a trick
for the old PHREEQE program, which include X- in the mole balance
equations. The free X- ion was forced to be small by this adjustment to the
log K's of the exchange reactions. In PHREEQC, the X- ion is not added into
the mole balance equations at all. The cation exchange reactions are half
reactions referenced to sodium (log K 0.0) in the default data bases.

David

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

Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled



                                                                                                                 
                      "Bruno Haerens"                                                                            
                      <bruno.haerens@xxxxxxxx        To:       <dlpark@xxxxxxxx>                                 
                      uven.ac.be>                    cc:                                                         
                                                     Subject:  selectivity coefficients                          
                      11/10/2003 06:10 AM                                                                        
                                                                                                                 
                                                                                                                 




Dear David,


Here I am again with a question:
In Appelo's paper in WRR (1994), he mentions in the comments of table 1,
that to all log KIX, 20 is added in PHREEQM. I guess this is als still the
case in PHREEQC-2, but I didn't find that in the manual.


Am I correct here?


Best regards,
Bruno









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/msg00573.html
Email:dlpark@usgs.gov
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 2235 since Jan 22, 1998.