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 complexes. 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. Birgit -----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
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 2239 since Jan 22, 1998.