Abstract
Potentiometric measurements of the stoichiometric constants for the dissociation of carbonic acid in NaCl solutions (K1* = [H+] [HCO3-] / [CO2] and K1* = [H+] [CO32 -] / [HCO3-]) have been made as a function of molality (0-6 m) and temperature (0-50 °C). The results have been fitted to the equationsp Ki* - p Ki = Ai + Bi / T + Ci ln TThe values of pKi in pure water are taken from the literature and the adjustable parameters Ai, Bi and Ci are a function of molalityA1 = 35.2911 m0.5 + 0.8491 m - 0.32 m1.5 + 0.055 m2B1 = - 1583.09 m0.5C1 = - 5.4366 m0.5A2 = 38.2746 m0.5 + 1.6057 m - 0.647 m1.5 + 0.113 m2B2 = - 1738.16 m0.5C2 = - 6.0346 m0.5(σ = 0.013 for p K1* and σ = 0.020 for p K2*, N = 603). The values determined in this study are in good agreement with the 25 °C literature values. Our results have been combined with previous measurements to derive equations that are valid from 0 to 250 °C and 0 to 5 m. This large data set has been used to determine the Pitzer parameters (β(0), β(1) and Cφ{symbol}) for the interactions of Na+ with HCO3- and CO32- from 0 to 250 °C. These results extend the carbonate system Pitzer model to hydrothermal brines containing high concentrations of NaCl.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 46-55 |
| Number of pages | 10 |
| Journal | Geochimica et Cosmochimica Acta |
| Volume | 71 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2007 |
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ASJC Scopus subject areas
- Geochemistry and Petrology
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The dissociation of carbonic acid in NaCl solutions as a function of concentration and temperature. / Millero, Frank J; Huang, Fen; Graham, Taylor; Pierrot, Denis.
In: Geochimica et Cosmochimica Acta, Vol. 71, No. 1, 01.01.2007, p. 46-55.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The dissociation of carbonic acid in NaCl solutions as a function of concentration and temperature
AU - Millero, Frank J
AU - Huang, Fen
AU - Graham, Taylor
AU - Pierrot, Denis
PY - 2007/1/1
Y1 - 2007/1/1
N2 - Potentiometric measurements of the stoichiometric constants for the dissociation of carbonic acid in NaCl solutions (K1* = [H+] [HCO3-] / [CO2] and K1* = [H+] [CO32 -] / [HCO3-]) have been made as a function of molality (0-6 m) and temperature (0-50 °C). The results have been fitted to the equationsp Ki* - p Ki = Ai + Bi / T + Ci ln TThe values of pKi in pure water are taken from the literature and the adjustable parameters Ai, Bi and Ci are a function of molalityA1 = 35.2911 m0.5 + 0.8491 m - 0.32 m1.5 + 0.055 m2B1 = - 1583.09 m0.5C1 = - 5.4366 m0.5A2 = 38.2746 m0.5 + 1.6057 m - 0.647 m1.5 + 0.113 m2B2 = - 1738.16 m0.5C2 = - 6.0346 m0.5(σ = 0.013 for p K1* and σ = 0.020 for p K2*, N = 603). The values determined in this study are in good agreement with the 25 °C literature values. Our results have been combined with previous measurements to derive equations that are valid from 0 to 250 °C and 0 to 5 m. This large data set has been used to determine the Pitzer parameters (β(0), β(1) and Cφ{symbol}) for the interactions of Na+ with HCO3- and CO32- from 0 to 250 °C. These results extend the carbonate system Pitzer model to hydrothermal brines containing high concentrations of NaCl.
AB - Potentiometric measurements of the stoichiometric constants for the dissociation of carbonic acid in NaCl solutions (K1* = [H+] [HCO3-] / [CO2] and K1* = [H+] [CO32 -] / [HCO3-]) have been made as a function of molality (0-6 m) and temperature (0-50 °C). The results have been fitted to the equationsp Ki* - p Ki = Ai + Bi / T + Ci ln TThe values of pKi in pure water are taken from the literature and the adjustable parameters Ai, Bi and Ci are a function of molalityA1 = 35.2911 m0.5 + 0.8491 m - 0.32 m1.5 + 0.055 m2B1 = - 1583.09 m0.5C1 = - 5.4366 m0.5A2 = 38.2746 m0.5 + 1.6057 m - 0.647 m1.5 + 0.113 m2B2 = - 1738.16 m0.5C2 = - 6.0346 m0.5(σ = 0.013 for p K1* and σ = 0.020 for p K2*, N = 603). The values determined in this study are in good agreement with the 25 °C literature values. Our results have been combined with previous measurements to derive equations that are valid from 0 to 250 °C and 0 to 5 m. This large data set has been used to determine the Pitzer parameters (β(0), β(1) and Cφ{symbol}) for the interactions of Na+ with HCO3- and CO32- from 0 to 250 °C. These results extend the carbonate system Pitzer model to hydrothermal brines containing high concentrations of NaCl.
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UR - http://www.scopus.com/inward/citedby.url?scp=33845477458&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2006.08.041
DO - 10.1016/j.gca.2006.08.041
M3 - Article
AN - SCOPUS:33845477458
VL - 71
SP - 46
EP - 55
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
IS - 1
ER -