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ion exchange
ion exchange The exchange of ions of the same charge between a solution (usually aqueous) and a solid in contact with it. The process occurs widely in nature, especially in the absorption and retention of water-soluble fertilizers by soil. For example, if a potassium salt is dissolved in water and applied to soil, potassium ions are absorbed by the soil and sodium and calcium ions are released from it. The soil, in this case, is acting as an ion exchanger. Synthetic ion-exchange resins consist of various copolymers having a cross-linked three-dimensional structure to which ionic groups have been attached. An anionic resin has negative ions built into its structure and therefore exchanges positive ions. A cationic resin has positive ions built in and exchanges negative ions. Ion-exchange resins are used as the stationary phase in ion-exchange chromatography.
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Cite this article
"ion exchange." A Dictionary of Biology. 2004. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. "ion exchange." A Dictionary of Biology. 2004. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O6-ionexchange.html "ion exchange." A Dictionary of Biology. 2004. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-ionexchange.html |
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ion exchange
ion exchange (IX) Reversible exchange of ions in a crystal for other ions in solution, without disturbance of the crystal lattice or its electrical neutrality. This occurs by diffusion, particularly in crystals where weakly bonded ions form one- or two-dimensional channelways. Natural zeolites are used to capture anions and cations from solution. Artificial ion-exchange resins with three-dimensional hydrocarbon networks are commonly used (e.g. in water softeners; for separating isotopes; in desalination; and in the chemical extraction of elements from ores).
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "ion exchange." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "ion exchange." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O13-ionexchange.html AILSA ALLABY and MICHAEL ALLABY. "ion exchange." A Dictionary of Earth Sciences. 1999. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-ionexchange.html |
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ion exchange
ion exchange (IX) The reversible exchange of ions for other ions in solution. Natural zeolites are used to capture anions and cations from solution. Artificial ion-exchange resins with three-dimensional hydrocarbon networks are commonly used (e.g. in water softeners, for separating isotopes, in desalination, and in the chemical extraction of elements from ores).
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Cite this article
MICHAEL ALLABY. "ion exchange." A Dictionary of Ecology. 2004. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "ion exchange." A Dictionary of Ecology. 2004. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O14-ionexchange.html MICHAEL ALLABY. "ion exchange." A Dictionary of Ecology. 2004. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-ionexchange.html |
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