Colloid-facilitated transport

Colloid-facilitated transport

Colloid-facilitated transport designates a transport process by which colloidal particles serve as transport vector [1] of diverse contaminants in the surface water (sea water, lakes, rivers, fresh water bodies) and in underground water circulating in fissured rocks [2] (limestone, sandstone, granite, ...). The transport of colloidal particles in surface soils and in the ground can also occur, depending on the soil structure, soil compaction, and the particles size, but the importance of colloidal transport was only given sufficient attention during the '1980 years. [3] Radionuclides, heavy metals, and organic pollutants, easily sorb onto colloids suspended in water and that can easily act as contaminant carrier.

Various types of colloids are recognised: inorganic colloids (clay particles, silicates, iron oxy-hydroxides, ...), organic colloids (humic and fulvic substances). When heavy metals or radionuclides form their own pure colloids, the term "Eigencolloid" is used to designate pure phases, e.g., Tc(OH)4, Th(OH)4, U(OH)4, Am(OH)3. Colloids have been suspected for the long range transport of plutonium on the Nevada Nuclear Test Site. They have been the subject of detailed studies for many years. However, the mobility of inorganic colloids is very low in compacted bentonites and in deep clay formations [4] because of the process of ultrafiltration occurring in dense clay membrane. [5] The question is less clear for small organic colloids often mixed in porewater with truly dissolved organic molecules. [6]

See also

External links

References

  1. ^ Frimmel, Fritz H.; Frank von der Kammer, Hans-Curt Flemming (2007). Colloidal transport in porous media (1 ed.). Springer. pp. 292. ISBN 3540713387, 9783540713388. http://www.springer.com/earth+sciences/book/978-3-540-71338-8?detailsPage=toc. 
  2. ^ Alonso, U.; T. Missana, A. Patelli, V. Rigato (2007). "Bentonite colloid diffusion through the host rock of a deep geological repository". Physics and Chemistry of the Earth, Parts A/B/C 32 (1-7): 469–476. Bibcode 2007PCE....32..469A. doi:10.1016/j.pce.2006.04.021. ISSN 1474-7065. http://www.sciencedirect.com/science/article/B6X1W-4M1TT1S-2/2/6518abfda3a7415ec2fef298c4b48636. Retrieved 2009-02-12. 
  3. ^ de Jonge, L.W.; C. Kjaergaard, P. Moldrup (2004). "Colloids and colloid-facilitated transport of contaminants in soils: An introduction". Vadose Zone Journal 3 (2): 321–325. doi:10.2113/3.2.321. http://vzj.scijournals.org/cgi/content/abstract/3/2/321. Retrieved 2009-02-24. 
  4. ^ Voegelin, A.; Kretzschmar, R. (December 2002) ([dead link]). Stability and mobility of colloids in Opalinus Clay.. Nagra Technical Report 02-14.. Institute of Terrestrial Ecology, ETH Zürich. pp. 47. ISSN 1015-2636. http://www.nagra.ch/documents/database/dokumente/%24default/Default%20Folder/Publikationen/e%5Fntb02%2D14.pdf 
  5. ^ "Diffusion of colloids in compacted bentonite". http://www.kth.se/che/divisions/nuchem/research/1.19965?l=en_UK. Retrieved 2009-02-12. 
  6. ^ Wold, Susanna; Trygve Eriksen (2007). "Diffusion of humic colloids in compacted bentonite". Physics and Chemistry of the Earth, Parts A/B/C 32 (1-7): 477–484. Bibcode 2007PCE....32..477W. doi:10.1016/j.pce.2006.05.002. ISSN 1474-7065. http://www.sciencedirect.com/science/article/B6X1W-4M33W74-2/2/6b38dd892861ead3f2e8605c78d8fd92. Retrieved 2009-02-12. 



Wikimedia Foundation. 2010.

Поможем сделать НИР

Look at other dictionaries:

  • Colloid — Milk is an emulsified colloid of liquid butterfat globules dispersed within a water based solution. A colloid is a substance microscopically dispersed evenly throughout another substance.[1] A colloidal system consists of two separate phases: a… …   Wikipedia

  • Nanoparticle — In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. Particles are further classified according to size[1] : in terms of diameter, coarse particles cover a range… …   Wikipedia

  • List of biochemistry topics — This page aims to list articles on Wikipedia that are related to biochemistry. This is so that those interested in the subject can monitor changes to the pages by clicking on .This list is not necessarily complete or up to date if you see an… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”