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

PHREEQC modeling

I am modeling cadmium transportation in consideration
of reactions-adsorption and precipitation/dissolution 
in a column packed with fly ash and bentonite mixture.

For this purpose, I performed batch experiments about
cadmium to know surface complexation properties 
and tracer experiments to know hydrogeological
parameters-seepage velocity and dispersion
coefficient- using lithium bromide. 
First to consider the adsorption properties of cadmium
on the mixture I used SURFACE_SPECIES and SURFACE. 
The column experiment of bromine was simulated using
And then, I combined two models of surface
complexatoin and conservative transport to simulate
non-conservative transport of cadmium. 
However, I found some problems about my results and
had questions about them.
1.       To define SURFACE, are SURFACE and their
total mass also divided by 10 if I divided column to
10 cells?
2.       In the case of my experiments, the removal
rate of cadmium was very low in a range of 5~200mg/L. 
    So I changed reaction constants (log_K) of
SURFACE_SPECIES to negative values. Is it caused any
3.       I performed breakthrough experiment for a
single ion of cadmium. But the BTC showed the shooting
    that appears in multi-ion (I mean the
concentration near the breakthrough is over the
initial concentration). 
    I think that result was caused by the other ions
that were defined for PHASES. How can I remove such a
4.       I included surface complexation to account
for the retardation of cadmium in a column. 
    So I expected that cadmium flowed out more slowly
in the low concentration. 
    Though I changed the initial concentrations from
50mg/L to 5mg/L, the breakthrough times are much the
    Why did the results appear?
I attach input files to e-mail. I know they may be
very clumsy and improper. I believe you will give me a
proper advice. 

예쁜 편지지에 메일을 보내세요 - 야후! 메일
신차,중고차,직거래 매물이 한자리에 - 야후! 자동차

Attachment: Inputfiles.zip
Description: Inputfiles.zip

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/msg00519.html
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 3489 since Jan 22, 1998.