PHREEQC (What else?)

["Katie Walton-Day" <kwaltond@xxxxxxxx>]

David,

Tino Maestas (Rick Healy's student) and I are attempting to model some
solutions we hope to use for some experiments.  We are mixing/diluting
standard solutions of dissolved metals.  Unfortunately, the pH values of
the starting solutions are about 0.5.  Are there any versions of PHREEQC
that will allow us to have solutions at that pH?  Is there a  discussion
area where I could go see if anyone has had a similar dilemma?

Also, as a first pass, we attempted to "make" DI water using water with a
pH = 7.0, Temperature of 25 degrees C, and in equilibrium with CO2.  We
modeled the gas phase two ways--For the first (input 2) we set pressure = 1
atm and adjusted the CO2 partial pressure to 0.000387 to account for the
elevation here (test2.out).  In the second, we set pressure = 0.81 atm, and
used a CO2 partial pressure of 0.000316 (test3.out).  Both yielded
essentially the same results except for pe. In the first simulation
(test2.out) the ending pe was 12.3.  In the second simulation (test3.out)
the final pe was 0.158.  When I use "redox   O(-2)/O(0)" the resulting pe
values match (test4.out). Any clues why they don't if I use "redox   pe"?

Thanks! Hope I'm not asking "stupid" questions.

Katie W-D

p.s I'm using version Phreeqci version R_0_30 that implements  PHREEQC
version 2.0.0

(See attached file: test2.out)(See attached file: test3.out)(See attached
file: test4.out)

Attachment: test2.out
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Attachment: test3.out
Description: Binary data

Attachment: test4.out
Description: Binary data