The pH of CO2-saturated water at temperatures between 308 K and 423 K at pressures up to 15 MPa
File(s)
Accepted version
Author(s)
Peng, C
Crawshaw, JP
Maitland, GC
Martin Trusler, JP
Vega-Maza, D
Type
Journal Article
Abstract
Abstract We report pH measurements for CO2-saturated water in the pressure range from (0.28 to 15.3) MPa and temperatures from (308.3 to 423.2) K. Commercially available pH and Ag/AgCl electrodes were used together with a high pressure equilibrium vessel operating under conditions of precisely controlled temperature and pressure. The results of the study indicate that pH decreases along an isotherm in proportion to −log10(x), where x is the mole fraction of dissolved CO2 in H2O. The expanded uncertainty of the pH measurements is 0.06 pH units with a coverage factor of 2. The reported results are in good agreement with the literature in pressure ranges up to 16 MPa at temperatures below 343 K. An empirical equation has been developed to represent the present results with an expanded uncertainty of 0.05 pH units. We also compare our results with a chemical equilibrium model and find agreement to within 0.1 pH unit.
Date Issued
2013-10
Date Acceptance
2013-07-15
Citation
The Journal of Supercritical Fluids, 2013, 82, pp.129-137
ISSN
0896-8446
Publisher
Elsevier
Start Page
129
End Page
137
Journal / Book Title
The Journal of Supercritical Fluids
Volume
82
Copyright Statement
© 2013 Elsevier B.V. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
http://www.sciencedirect.com/science/article/pii/S0896844613002441
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Engineering, Chemical
Chemistry
Engineering
CHEMISTRY, PHYSICAL
ENGINEERING, CHEMICAL
Carbon dioxide
High pressure
High temperature
pH
Water
CARBON-DIOXIDE
ELEVATED-TEMPERATURES
SEQUESTRATION
SEAWATER
ACID
MODEL
CO2
IONIZATION
CONSTANTS
MIXTURE
Chemical Engineering
03 Chemical Sciences
05 Environmental Sciences
09 Engineering
Notes
Abstract We report pH measurements for CO2-saturated water in the pressure range from (0.28 to 15.3) MPa and temperatures from (308.3 to 423.2) K. Commercially available pH and Ag/AgCl electrodes were used together with a high pressure equilibrium vessel operating under conditions of precisely controlled temperature and pressure. The results of the study indicate that pH decreases along an isotherm in proportion to −log10(x), where x is the mole fraction of dissolved CO2 in H2O. The expanded uncertainty of the pH measurements is 0.06 pH units with a coverage factor of 2. The reported results are in good agreement with the literature in pressure ranges up to 16 MPa at temperatures below 343 K. An empirical equation has been developed to represent the present results with an expanded uncertainty of 0.05 pH units. We also compare our results with a chemical equilibrium model and find agreement to within 0.1 pH unit.
Publication Status
Published