TY - JOUR
T1 - Dawsonite synthesis and reevaluation of its thermodynamic properties from solubility measurements
T2 - Implications for mineral trapping of CO2
AU - Bénézeth, Pascale
AU - Palmer, Donald A.
AU - Anovitz, Lawrence M.
AU - Horita, Juske
N1 - Funding Information:
This research was sponsored by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy, under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC. Thanks to J.C. Harrichoury from the Laboratoire des Mécanismes de Transfert en Géologie for his help in synthesizing dawsonite (Daws-D), and Michel Thibaut for some of the XRD analyses. This manuscript was greatly improved by thorough reviews by A. Mucci (Associate Editor), J.P. Kaszuba, K.G. Knauss and an anonymous reviewer.
PY - 2007/9/15
Y1 - 2007/9/15
N2 - Over the last decade, a significant research effort has focused on determining the feasibility of sequestering large amounts of CO2 in deep, permeable geologic formations to reduce carbon dioxide emissions to the atmosphere. Most models indicate that injection of CO2 into deep sedimentary formations will lead to the formation of various carbonate minerals, including the common phases calcite (CaCO3), dolomite (CaMg(CO3)2), magnesite (MgCO3), siderite (FeCO3), as well as the far less common mineral, dawsonite (NaAlCO3(OH)2). Nevertheless, the equilibrium and kinetics that control the precipitation of stable carbonate minerals are poorly understood and few experiments have been performed to validate computer codes that model CO2 sequestration. In order to reduce this uncertainty we measured the solubility of synthetic dawsonite according to the equilibrium: NaAlCO3 (OH)2 (cr) + 2 H2 O(l) ⇌ Al(OH)4- + HCO3- + Na+ + H+, from under- and oversaturated solutions at 50-200 °C in basic media at 1.0 mol · kg-1 NaCl. The solubility products (Qs) obtained were extrapolated to infinite dilution to obtain the solubility constants (Kso). Combining the fit of these log Kso values and fixing Δ Cp, ro at - 185.5 J · mol- 1 · K- 1 at 25 °C, which was derived from the calorimetric data of Ferrante et al. [Ferrante, M.J., Stuve, J.M., and Richardson, D.W., 1976. Thermodynamic data for synthetic dawsonite. U.S. Bureau of Mines Report Investigation, 8129, Washington, D.C., 13p.], the following thermodynamic parameters for the dissolution of dawsonite were calculated at 25 °C: Δ Gro = 102.1 kJ · mol- 1, Δ Hro = 97.0 kJ · mol- 1 and Δ Sro = - 17.1 J · mol- 1 · K- 1. Subsequently, we were able to derive values for the Gibbs energy of formation (Δf G298.15o = - 1782 ± 2 kJ · mol- 1), enthalpy of formation (Δf H298.15o = - 1960 ± 7 kJ · mol- 1) and entropy (S298.15o = 131 ± 2 J · mol- 1 · K- 1) of dawsonite. These results are within the combined experimental uncertainties of the values reported by Ferrante et al. (1976). Predominance diagrams are presented for the dawsonite/boehmite and dawsonite/bayerite equilibria at 100 °C in the presence of a saline solution with and without silica-containing minerals.
AB - Over the last decade, a significant research effort has focused on determining the feasibility of sequestering large amounts of CO2 in deep, permeable geologic formations to reduce carbon dioxide emissions to the atmosphere. Most models indicate that injection of CO2 into deep sedimentary formations will lead to the formation of various carbonate minerals, including the common phases calcite (CaCO3), dolomite (CaMg(CO3)2), magnesite (MgCO3), siderite (FeCO3), as well as the far less common mineral, dawsonite (NaAlCO3(OH)2). Nevertheless, the equilibrium and kinetics that control the precipitation of stable carbonate minerals are poorly understood and few experiments have been performed to validate computer codes that model CO2 sequestration. In order to reduce this uncertainty we measured the solubility of synthetic dawsonite according to the equilibrium: NaAlCO3 (OH)2 (cr) + 2 H2 O(l) ⇌ Al(OH)4- + HCO3- + Na+ + H+, from under- and oversaturated solutions at 50-200 °C in basic media at 1.0 mol · kg-1 NaCl. The solubility products (Qs) obtained were extrapolated to infinite dilution to obtain the solubility constants (Kso). Combining the fit of these log Kso values and fixing Δ Cp, ro at - 185.5 J · mol- 1 · K- 1 at 25 °C, which was derived from the calorimetric data of Ferrante et al. [Ferrante, M.J., Stuve, J.M., and Richardson, D.W., 1976. Thermodynamic data for synthetic dawsonite. U.S. Bureau of Mines Report Investigation, 8129, Washington, D.C., 13p.], the following thermodynamic parameters for the dissolution of dawsonite were calculated at 25 °C: Δ Gro = 102.1 kJ · mol- 1, Δ Hro = 97.0 kJ · mol- 1 and Δ Sro = - 17.1 J · mol- 1 · K- 1. Subsequently, we were able to derive values for the Gibbs energy of formation (Δf G298.15o = - 1782 ± 2 kJ · mol- 1), enthalpy of formation (Δf H298.15o = - 1960 ± 7 kJ · mol- 1) and entropy (S298.15o = 131 ± 2 J · mol- 1 · K- 1) of dawsonite. These results are within the combined experimental uncertainties of the values reported by Ferrante et al. (1976). Predominance diagrams are presented for the dawsonite/boehmite and dawsonite/bayerite equilibria at 100 °C in the presence of a saline solution with and without silica-containing minerals.
UR - http://www.scopus.com/inward/record.url?scp=34548523302&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2007.07.003
DO - 10.1016/j.gca.2007.07.003
M3 - Article
AN - SCOPUS:34548523302
SN - 0016-7037
VL - 71
SP - 4438
EP - 4455
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 18
ER -