Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-20T01:50:12.350Z Has data issue: false hasContentIssue false

Probing the Fractal Character of Pore Surfaces in Shale with Adsorption Technique

Published online by Cambridge University Press:  10 February 2011

Jian Ma
Affiliation:
Department of Physics, Amherst College, Amherst, MA 01002
Hao Qi
Affiliation:
Department of Physics, University of Massachusetts, Amherst, MA 01002
Po-Zen Wong
Affiliation:
Department of Physics, University of Massachusetts, Amherst, MA 01002
Get access

Abstract

We report on an adsorption study on two shale samples that have previously been investigated by small-angle neutron scattering (SANS). The scattering data indicate that these samples can be characterized as surface fractals in length from 5 Å to 500 Å, with the fractal dimension D between 2.83 and 2.75. Using the existing models for adsorption on fractal surfaces, the values of D deduced from the adsorption data appear to be consistently lower than the SANS results. We discuss these findings.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Pfeifer, P. and Avnir, D., J. Chem. Phys. 79, p. 3558 (1983); and D. Avnir, D. Frain and P. Pfeifer, Nature (London) 308, p. 261 (1984).Google Scholar
2. Katz, A. J. and Thompson, A. H., Phys. Rev. Lett. 54, p. 1325 (1985); and H.D. Bale and P.W. Schmidt, Phys. Rev. Lett. 53, p. 596 (1984).Google Scholar
3. Po-zen, Wong, James, Howard and Jar-Shyong, Lin, Phys. Rev. Lett. 57, p. 637 (1986).Google Scholar
4. Gregg, S. J. and Sing, K. S. W., Adsorption, Surface Area and Porosity (Academic, New York, 1982), pp. 4172.Google Scholar
5. Gregg, S. J. and Sing, K. S. W., Adsorption, Surface Area and Porosity (Academic, New York, 1982), pp. 111121.Google Scholar
6. de Gennes, P.G., in Physics and Chemistry of Disordered Materials, edited by Alder, D., Fritsche, H. and Ovshinsky, S. R. (Plenum, New York, 1985), p. 227; D. Avnir and M. Jaroniec, Langmuir 5, p. 1431 (1989); and Y. Yin, Langmuir 7, 216 (1991).Google Scholar
7. Pfeifer, P. and Cole, M. W., New J. Chem 14, p. 221 (1990).Google Scholar
8. Neimark, A. V., JETP Lett. 51, p. 607 (1990).Google Scholar
9. See, e.g., CRC Handbook of Physics and Chemistry, 58th ed., Weast, R. C., ed. (CRC Press, West Palm Beach, 1977.)Google Scholar
10. A proper fractal analysis should use only the adsorption branch of the isotherm above 40 torr. The reason that the desorption branch is not applicable is that on desorption the pores in the interior of the sample that satisfy Eq. (3) cannot empty until those on the outer part have emptied, so that they can have access to the surrounding vapor. This accessibility is not an issue on adsorption.Google Scholar
2. For a more detailed discussion, see Jian Ma, Hao Qi and Po-zen Wong, Phys. Rev. E, in press, 1999.Google Scholar