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Encyclopedia > Ion exchange

Ion exchange is defined as an exchange of ions between two electrolytes. However, words ion exchange are more conventionally used to denote processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with use of solid ion exchangers. In ion exchange processes ions are exchanged between a solution and an ion exchanger, a non-aqueous solid or gel. Typical ion exchangers are ion exchange resins, zeolite, montmorillonite, clay, and humus. Ion exchangers are either cation exchangers for positively charged cations or anion exchangers for negatively charged anions. There are also amphoteric exchangers that are able to exchange both cations and anions simultaneously. However, the simultaneous exchange of cations and anions is more efficiently performed in ion exchange reactors called mixed beds which contain mixed anion and cation exchange resins. Ion exchange is a reversible process and the ion exchanger can be regenerated or loaded with desirable ions by washing with an excess of these ions. ... Dissolving table salt (NaCl) in water This article is about a chemical solution; for other uses of the term solution, see solution (disambiguation). ... In optical filters and theatrical lighting a color gel is a transparent or translucent colored panel used to change the color of transmitted light. ... Ion exchange resin beads An ion exchange resin is an insoluble matrix (or support structure) normally in the form of small (1-2 mm diameter) beads, usually white or yellowish, fabricated from an organic polymer substrate on the surface of which are sites with easily trapped and released ions in... Zeolite The micro-porous molecular structure of a zeolite, ZSM-5 Zeolites (Greek, zein, to boil; lithos, a stone) are minerals that have a micro-porous structure. ... A sample of montmorillonite Montmorillonite is a very soft phyllosilicate mineral that typically forms in microscopic crystals, forming a clay. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... Humus is a word actually used for two different things, which are both related to soil and thus get used interchangeably. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... A cation is an ion with positive charge. ... An anion is an ion with negative charge. ... In thermodynamics, a reversible process (or reversible cycle if the process is cyclic) is a process that can be reversed by means of infinitesimal changes in some property of the system (Sears and Salinger, 1986). ...


Ion exchange is a method widely used in household and industrial water purifications to produce soft water. This is accomplished by exchanging calcium Ca2+ and magnesium Mg2+ cations against sodium Na+ or hydrogen H+ cations (see Water softening). However, the field where ion exchange is the most economically efficient is ionic separations where a product of highest purity must be obtained, an ion contained in a low concentration must be extracted, or streams of varying composition must be treated. Thus a typical example of application is preparation of high purity water for electronic and nuclear industries. Control room and schematics of the water purification plant to Bret lake. ... Soft water is water which has a relatively low concentration of minerals—particularly Calcium and Magnesium—dissolved in it. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... A water hardener reduces the calcium or magnesium ion concentration in hard water. ...


Ion exchange chromatography is a chromatographical method that is widely used for chemical analysis and separation of ions. For example, in biochemistry it is widely used to separate charged molecules such as proteins. Ion-exchange chromatography, or the more general ion chromatography, is a process that allows the separation of ions and polar molecules based on the charge properties of the molecules. ... Pictured is a sophisticated gas chromatography system. ... Biochemistry is the study of the chemical processes and transformations in living organisms. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...


Ion Exchange is also widely used in the food & beverage, hydrometallurgical, metals finishing, chemical & petrochemical, pharmaceutical, sugar & sweeteners, ground & potable water, nuclear, softening & industrial water, semiconductor, power, and a host of other industries.


References

  • F. Helfferich, Ion Exchange, McGraw Hill, New York, 1962 (Bible of the subject).
  • Ion Exchangers (K. Dorfner, ed.), Walter de Gruyter, Berlin, 1991.
  • Ion exchange (D. Muraviev, V. Gorshkov, A. Warshawsky), M. Dekker, New York, 2000.
  • A. A. Zagorodni, Ion Exchange Materials: Properties and Applications, Elsevier, Amsterdam, 2006.

External links

  • Illustrated and well defined chemistry lab practical on ion exchange from Dartmouth College
  • Some applets illustrating ion exchange processes

  Results from FactBites:
 
Ion Exchange (IE) (1002 words)
Ion Exchange (IE) and adsorption processes mastered by Novasep Process (via Applexion) are based on competitive interactions of species contained in a (moving) liquid phase with specific chemical sites of a solid phase (also referred to as the resin or the adsorbent).
Ion exchange resins consist in a polymeric matrix and a functional group with a mobile ion which can be exchanged with other ions present in the solution to be treated.
Ion exchange resins are mostly available in a moist beads form (granular or powdered forms are also sometime used, dry form is also available for applications in a solvent media) with a particle size distribution typically ranging 0.3 – 1.2 mm (16 – 50 mesh) with a gel or macroporous structure.
ion exchange : ion exchange resins (APPLEXION, XA) (195 words)
ion exchange : ion exchange resins (APPLEXION, XA)
Under XA designation a comprehensive list of ion exchange resins are available for numerous applications and designs.
Before loading a column with ion exchange resins it is important to observe a precise procedure for the filling of the columns, the backwashing of the resins and the conditioning prior to use.
  More results at FactBites »

 
 

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