Abstract
Solutions under sub- or supercritical conditions receive much attention because of their significance in geology and industrial applications. One of the most important properties is their very low salt solubility, which leads to rapid crystallization. The morphology of sodium chloride crystals formed in supercritical fluids has been shown to be affected by the presence of the high-concentration liquid phase and low-concentration vapor phase [Armellini and Tester, J. Supercritical Fluid 4, 254–264 (1991)]. However, because of the short time scales involved, experimental observation of the underlying mechanism is difficult. In the present study, microsecond-scale molecular dynamics, which provide insight with picosecond resolution, were conducted for the NaCl salt–solution interfacial system at sub- and super-critical conditions. We propose the utilization of the correlation between the number density of ions and water to parameterize the solution phase. This correlation and the two-dimensional number densities provide insight into flash crystallization at the atomic scale. Vapor–liquid phase coexistence was found at high pressure and the diffusive high-concentration liquid phase could transport sodium and chloride ions to form a compact solid phase. In contrast, an isolated crystal forms at low pressure owing to the rapid volume expansion of the vapor phase.
Similar content being viewed by others
References
Armellini, F.J., Tester, J.W.: Experimental methods for studying salt nucleation and growth from supercritical water. J. Supercrit. Fluids 4, 254–264 (1991)
Armellini, F.J., Tester, J.W., Hong, G.T.: Precipitation of sodium chloride and sodium sulfate in water from sub- to supercritical conditions: 150 to 550 \(^{\circ }\)C, 100 to 300 bar. J. Supercrit. Fluids 7, 147–158 (1994)
Hovland, M., Kuznetsova, T., Rueslatten, H., Kvamme, B., Johnsen, H.K., Fladmark, G.E., Hebach, A.: Sub-surface precipitation of salts in supercritical seawater. Basin Res. 18, 221–230 (2006)
Butterfield, D.A., Mcduff, R.E., Mottl, M.J., Lilley, M.D., Lupton, J.E., Massoth, G.J.: Gradients in the composition of hydrothermal fluids from the Endeavour segment vent field; phase separation and brine loss. J. Geophys. Res. 99, 9561–9583 (1994)
Koschinsky, A., Garbe-Schonberg, D., Sander, S., Schmidt, K., Gennerich, H., Stauss, H.: Hydrothermal venting at pressure–temperature conditions above the critical point of seawater, 5\(^{\circ }\)S on the Mid-Atlantic Ridge. Geology 36, 615–618 (2008)
Kitazono, S., Ueno, H.: Mineralogical and genetical aspects of the Doyashiki Kuroko Deposits, Hokuroku Basin, Japan. Resour. Geol. 53, 143–153 (2003)
Massoth, G.J., Butterfield, D.A., Lupton, J.E., McDuff, R.E., Lilley, M.D., Jonasson, I.R.: Submarine venting of phase-separated hydrothermal fluids at Axial Volcano Juan de Fuca Ridge. Nature 340, 702–705 (1989)
Von Damm, K.L.: Chemistry of hydrothermal vent fluids from 9\(^{\circ }\)-10\(^{\circ }\)N, East Pacific Rise: “Time zero”, the immediate posteruptive period. J. Geophys. Res. 105, 11203–11222 (2000)
Butterfield, D.A., Massoth, G.J., McDuff, R.E., Lupton, J.E., Lilley, M.: Geochemistry of hydrothermal fluids from axial seamount hydrothermal emissions study vent field, Juan de Fuca Ridge: Subseafloor boiling and subsequent fluid–rock interaction. J. Geophys. Res. 95, 12895–12921 (1990)
Haymon, R.M., Fornari, D.J., Von Damm, K.L., Lilley, M.D., Perfit, M.R., Edmond, J.M., Shanks III, W.C., Lutz, R.A., Grebmeier, J.M., Carbotte, S., Wright, D., McLaughlin, E., Smith, M., Beedle, N., Olson, E.: Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9\(^{\circ }\)45–52’N: Direct submersible observations of seafloor phenomena associated with an eruption event in April, 1991. Earth and Planet. Sci. Lett. 119, 85–101 (1993)
Moss, R., Scott, S.D.: Geochemistry and mineralogy of gold-rich hydrothermal precipitates from the Eastern Manus Basin Papua New Guinea. Can. Mineral. 39, 957–978 (2001)
Hannington, M., Herzig, P., Stoffers, P., Scholten, J., Botz, R., Garbe-Schonberg, D., Jonasson, I.R., Roest, W.: Shipboard scientific party, first observations of high-temperature submarine hydrothermal vents and massive anhydrite deposits off the north coast of Iceland. Mar. Geol. 177, 199–220 (2001)
Hirschmann, M., Kohlstedt, D.: Water in earth’s mantle. Phys. Today 65, 40–45 (2012)
Bermejo, M.D., Cocero, M.J.: Supercritical water oxidation: a technical review. AIChE J. 52, 3933–3951 (2006)
Hess, B., Kutzner, C., van der Spoel, D., Lindahl, E.: GROMACS 4: algorithms for highly efficient, load-balanced and scalable molecular simulation. J. Chem. Theory Comput. 4, 435–447 (2008)
Berendsen, H.J.C., Grigera, J., Staatsma, T.: The missing term in effective pair potentials. J. Phys. Chem. 91, 6269–6271 (1987)
Alejandre, J., Tildesley, D., Chapela, G.: Molecular dynamics simulation of the orthobaric densities and surface tension of water. J. Chem. Phys. 102, 4574–4583 (1995)
Joung, I.S., Cheatham III, T.E.: Determination of alkali and halide monovalent ion parameters for use in explicitly solvated bio molecular simulations. J. Phys. Chem. B 112, 9020–9071 (2008)
Joung, I.S., Cheatham III, T.E.: Molecular dynamics simulations of the dynamic and energetic properties of alkali and halide ions using water-model-specific ion parameters. J. Phys. Chem. B 113, 13279–13290 (2009)
Kobayashi, K., Liang, Y., Sakka, T., Matsuoka, T.: Molecular dynamics study of salt–solution interface: Solubility and surface charge of salt in water. J. Chem. Phys. 140, 144705 (2014)
Bischoff, J.L., Pitzer, K.S.: Liquid–vapor relations for the system NaCl–H\(_2\)O: Summary of the P–T–x surface from 300\(^{\circ }\) to 500 °C. Am. J. Sci. 289, 217–248 (1989)
Pitzer, K.S.: Aqueous electrolytes at near-critical and supercritical temperatures. Int. J. Thermophys. 19, 355–365 (1998)
Drriesner, T., Heinrich, C.A.: The system H\(_2\)O–NaCl. Part I: Correlation formulae for phase relations in temperature–pressure–composition space from 0 to 1000 °C, 0 to 5000 bar and 0 to 1 \(X_{\rm NaCl}\). Geochim. Cosmochim. Acta 71, 4880–4901 (2007)
Walther, J.V.: Essential of Geochemistry, p. 137. Jones and Bartlett Publishers, Massachusetts (2009)
Nose, S.: A molecular dynamics method for simulations in the canonical ensemble. Mol. Phys. 52, 255–268 (1984)
Parrinello, M., Rahman, A.: Polymorphic transitions in single crystals: A new molecular dynamics method. J. Appl. Phys. 52, 7182–7190 (1981)
Humphrey, W., Dalke, A., Schulten, K.: VMD: Visual molecular dynamics. J. Mol. Graphics 14, 33–38 (1996)
Acknowledgments
The authors acknowledge the financial support of the Japanese Society for the Promotion of Science (JSPS) through a Grant-in-Aid for Scientific Research A (No. 24246148), JOGMEC, JST/JICA-SATREPS, and JAPEX. We also wish to thank Yasuhiro Fukunaka for valuable discussions.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kobayashi, K., Liang, Y. & Matsuoka, T. Molecular Dynamics Study of Aqueous NaCl Solutions: Flash Crystallization Caused by Solution Phase Change. J Solution Chem 43, 1799–1809 (2014). https://doi.org/10.1007/s10953-014-0247-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10953-014-0247-3