CHEMICO-OSMOSIS VERSUS DIFFUSION-OSMOSIS

During the 1960s it became widely recognized that chemico-osmsis is a mechanism by which chemical gradients cause groundwater to move from dilute to more concentrated pore-fluid solutions and is most effective in densely compacted materials of high exchange capacity. Evidence has been accumulating since about 1970 that an additional mechanism may cause groundwater movement in response to chemical gradients and reactions. Some data show that the direction of soil-pore-fluid movement in response to a concentration gradient is opposite to that of chemico-osmosis. Other data suggest that chemically induced groundwater movement may be significant not only in densely compacted materials of high exchange capacity but also in poorly consolidated materials of low exchange capacity. Laboratory evidence is reviewed for the additional mechanism and include recent data on loosely compacted kaolinite and an undistrubed sample of claystone. The additional mechanism appears to be diffusion-osmosis (i.e., the convection, or drag, of bulk pore fluid by the diffusion of solute species). It is suggested that electro-osmosis is a special case of diffusion-osmosis where pore fluid moves in response to the migration of solute species caused by an externally imposed electrical potential gradient.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1990/1288/1288-003.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=CHEMICO-OSMOSIS+VERSUS+DIFFUSION-OSMOSIS&author=H.+Olsen&author=E.+Yearsley&author=K.+Nelson&publication_year=1990
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• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1288, Geotechnical Engineering 1990. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Olsen, Harold W
  • Yearsley, Elliot N
  • Nelson, Karl R
• Publication Date: 1990

Media Info

• Features: Figures; References;
• Pagination: p. 15-22
• Monograph Title: Geotechnical engineering 1990 - soils, geology and foundations
• Serial:
  • Transportation Research Record
  • Issue Number: 1288
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Clay; Clay minerals; Groundwater; Kaolinite; Osmosis
• Old TRIS Terms: Chemico-osmosis; Claystones; Diffusion-osmosis
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;

Filing Info

• Accession Number: 00607746
• Record Type: Publication
• ISBN: 0309050642
• Files: TRIS, TRB
• Created Date: Apr 30 1991 12:00AM