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

PHREEQ-C question

Mr. Parkhurst,

I have a question for you about PHREEQ-C: you mention in the manual that the
usage of mole fraction for the activity of surface species instead of
molarity (which sounds reasonable to me) does affect multidentate
complexes - I'd be interested in how this affects bi- or tridentate

In addition, I was wondering if it is possible to include surface
precipitation as well in PHREEQ-C (accounting for the phenomenon that near
the surface concentrations may be high enough for precipitation whereas
overall solution concentrations are too low for precipitation to occur).
I simulated As(V) sorption onto a quartz sand using the diffuse double layer
model, and I had some problems at "higher" As(V) concentrations - at 10^-7
and 10^-8 moles/l As(V) the model works fine, but it underpredicts sorption
at 10^-6 moles/l and I was wondering if that could be due to bidentate
complexes involved (which was observed in other studies) or surface
precipitation with dissolved Fe.

Thanks for you help.

-----Original Message-----
From: David L Parkhurst [mailto:dlpark@xxxxxxxx]
Sent: Thursday, February 13, 2003 4:37 PM
To: Birgit Braun
Subject: Re: PHREEQ-C mailing list

Ok. Your name will be added to the PHREEQC mailing list.

Dipl.-Ing. Birgit Braun, M.S.
Reserach Associate
Colorado School of Mines
Department of Environmental Science and Engineering
Golden, CO 80401
Phone: (303) 384 2116
Email: bbraun@xxxxxxxxx

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/msg00138.html
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 1952 since Jan 22, 1998.