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Date: | Mon, 10 Nov 1997 10:18:16 -0500 |
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Dear Dachun,
like Elena mentioned, you probably see an isotope salt effect.
In addition to the references given by Elena you may want to check:
1) These are the two classic papers that got the business started (and as
far as I know an early part of the work for which Taube received the Noble
Prize). And they have data for the effect of HCl ...
Feder H. M. and Taube H. (1952) Ionic hydration: An isotopic
fractionation technique. J. Chem. Phys. 20, 1335-1336
Taube H. (1954) Use of oxygen isotope effects in the study of hydration of
ions. J. Phys. Chem. 58, 523-528
2) Although not directly important for your measurments, I'd like to
point out that the high temperature data in the Truesdell paper metioned
by Elena have been shown to be wrong. Poulson et al's data are very
scattered and Zhang et al.'s are not very meaningful. For elevated T's one
should rather use the very accurate data of Juske Horita et al.:
Horita et al. (1993a): Geochim. Cosmochim Acta 57, 2197-2817
Horita et al.. (1993b): Geochim. Cosmochim Acta 57, 4703-4711
Horita et al. (1995) : Geochim. Cosmochim Acta 59, 1139-1151
The 1993a paper also has a collection of all measured data up to then.
3) You may also want to check the exchange kinetics for the CO2
equilobration technique. For salt solutions, check out
Fortier (1994): Chem. Geol. (Isotope Geoscience) 116, 155-162
4) I'd like to mention that salt effects are also present (and by no means
small or trivial) for hydrogen isotopes (again see the Horita papers and
references therein). Both the effects on O and H isotopes MUST be
considered in any study of fluid-rock interaction since we rarely deal
with pure water ...
Regards
Thomas
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Thomas Driesner
Dept. of Chemical Engineering
419 Dougherty Engineering
University of Tennessee
Knoxville, TN 37996-2200
Tel. (423) 974-0553
Fax (423) 974-4910
e-mail [log in to unmask]
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