Abstract

Thermodynamic properties of fluids confined in nanopores differ from those observed in the bulk. To investigate the effect of nanoconfinement on water compressibility, we perform water sorption experiments on two nanoporous glass samples while concomitantly measuring the speed of longitudinal and shear ultrasonic waves in these samples. These measurements yield the longitudinal and shear moduli of the water-laden nanoporous glass as a function of relative humidity that we utilize in the Gassmann theory to infer the bulk modulus of the confined water. This analysis shows that the bulk modulus (inverse of compressibility) of confined water is noticeably higher than that of the bulk water at the same temperature. Moreover, the modulus exhibits a linear dependence on the Laplace pressure. The results for water, which is a polar fluid, agree with previous experimental and numerical data reported for nonpolar fluids. This similarity suggests that irrespective of intermolecular forces, confined fluids are stiffer than bulk fluids. Accounting for fluid stiffening in nanopores may be important for accurate interpretation of wave propagation measurements in fluid-filled nanoporous media, including in petrophysics, catalysis, and other applications, such as in porous materials characterization.

RAS ID

62068

Document Type

Journal Article

Date of Publication

8-1-2023

Volume

108

Issue

2

Funding Information

National Science Foundation

School

School of Engineering / Centre for Sustainable Energy and Resources

Grant Number

CBET-2128679

Copyright

© American Physical Society

Publisher

American Physical Society

Comments

© American Physical Society

Ogbebor, J., Valenza, J. J., Ravikovitch, P. I., Karunarathne, A., Muraro, G., Lebedev, M., . . . Gor, G. Y. (2023). Ultrasonic study of water adsorbed in nanoporous glasses. Physical Review E, 108, article 024802. https://doi.org/10.1103/PhysRevE.108.024802

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Link to publisher version (DOI)

10.1103/PhysRevE.108.024802