WordNet

hand over one and receive another, approximately equivalent; "exchange prisoners"; "exchange employees between branches of the company"
chemical process in which one atom or ion or group changes places with another
reciprocal transfer of equivalent sums of money (especially the currencies of different countries); "he earns his living from the interchange of currency" (同)interchange
the act of changing one thing for another thing; "Adam was promised immortality in exchange for his disobedience"; "there was an interchange of prisoners" (同)interchange
(chess) gaining (or losing) a rook in return for a knight or bishop; "black lost the exchange"
(chess) the capture by both players (usually on consecutive moves) of pieces of equal value; "the endgame began after the exchange of queens"
a workplace for buying and selling; open only to members
the act of giving something in return for something received; "deductible losses on sales or exchanges of property are allowable"
a mutual expression of views (especially an unpleasant one); "they had a bitter exchange"
give to, and receive from, one another; "Would you change places with me?"; "We have been exchanging letters for a year" (同)change, interchange
a positively charged ion
one whose business is to exchange the money of one country for that of another country (同)money changer

PrepTutorEJDIC

…‘を'『取り替える』;(…と)…‘を'取り替える《+『名』+『for』+『名』》 / …‘を'『取り交わす』;(人と)…‘を'取り交わす《+『名』+『with』+『名』〈人〉》 / (化幣が)両替される / 〈U〉〈C〉(物の物との)『取り替え』《+『of』+『名』+『for』+『名』》;(相手と物を)『交換すること』《+『of』+『名』(複数)+『with』+『名』〈人〉》 / 〈C〉交換物,取り替え品 / 〈C〉取引所;(電話の)交換局 / 〈U〉両替;為替(かわせ),為替相場 / 〈C〉=employment exchange
陽イオン,正イオン

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/19 04:06:21」(JST)

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Ion exchanger

Ion exchange resin beads

Ion exchange column, used for protein purification

Ion exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid polymeric or mineralic 'ion exchangers'.

Typical ion exchangers are ion exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus. Ion exchangers are either cation exchangers that exchange positively charged ions (cations) or anion exchangers that exchange negatively charged ions (anions). There are also amphoteric exchangers that are able to exchange both cations and anions simultaneously. However, the simultaneous exchange of cations and anions can be more efficiently performed in mixed beds that contain a mixture of anion and cation exchange resins, or passing the treated solution through several different ion exchange materials.

Ion exchangers can be unselective or have binding preferences for certain ions or classes of ions, depending on their chemical structure. This can be dependent on the size of the ions, their charge, or their structure. Typical examples of ions that can bind to ion exchangers are:

H⁺ (proton) and OH⁻ (hydroxide)
Single-charged monatomic ions like Na⁺, K⁺, and Cl⁻
Double-charged monatomic ions like Ca²⁺ and Mg²⁺
Polyatomic inorganic ions like SO₄²⁻ and PO₄³⁻
Organic bases, usually molecules containing the amine functional group -NR₂H⁺
Organic acids, often molecules containing -COO⁻ (carboxylic acid) functional groups
Biomolecules that can be ionized: amino acids, peptides, proteins, etc.

Along with absorption and adsorption, ion exchange is a form of sorption.

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.

Applications

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

Most typical example of application is preparation of high purity water for power engineering, electronic and nuclear industries; i.e. polymeric or mineralic insoluble ion exchangers are widely used for water softening, water purification, water decontamination, etc.

Ion exchange is a method widely used in household (laundry detergents and water filters) to produce soft water. This is accomplished by exchanging calcium Ca²⁺ and magnesium Mg²⁺ cations against Na⁺ or H⁺ cations (see water softening). Another application for ion exchange in domestic water treatment is the removal of nitrate and natural organic matter.

Industrial and analytical ion exchange chromatography is another area to be mentioned. 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. An important area of the application is extraction and purification of biologically produced substances such as proteins (amino acids) and DNA/RNA.

Ion-exchange processes are used to separate and purify metals, including separating uranium from plutonium and other actinides, including thorium, and lanthanum, neodymium, ytterbium, samarium, lutetium, from each other and the other lanthanides. There are two series of rare earth metals, the lanthanides and the actinides, both of whose families all have very similar chemical and physical properties. Using methods developed by Frank Spedding in the 1940s, ion-exchange used to be the only practical way to separate them in large quantities, until the advent of solvent extraction techniques that can be scaled up enormously.

A very important case is the PUREX process (plutonium-uranium extraction process), which is used to separate the plutonium and the uranium from the spent fuel products from a nuclear reactor, and to be able to dispose of the waste products. Then, the plutonium and uranium are available for making nuclear-energy materials, such as new reactor fuel and nuclear weapons.

The ion-exchange process is also used to separate other sets of very similar chemical elements, such as zirconium and hafnium, which is also very important for the nuclear industry. Zirconium is practically transparent to free neutrons, used in building reactors, but hafnium is a very strong absorber of neutrons, used in reactor control rods.

Ion exchangers are used in nuclear reprocessing and the treatment of radioactive waste.

Ion exchange resins in the form of thin membranes are used in chloralkali process, fuel cells and vanadium redox batteries.

Large cation/anion ion exchangers used in water purification of boiler feedwater.^[1]

Ion exchange can also be used to remove hardness from water by exchanging calcium and magnesium ions for sodium ions in an ion exchange column. Liquid (aqueous) phase ion exchange desalination has been demonstrated.^[2] In this technique anions and cations in salt water are exchanged for carbonate anions and calcium cations respectively using electrophoresis. Calcium and carbonate ions then react to form calcium carbonate, which then precipitates leaving behind fresh water. The desalination occurs at ambient temperature and pressure and requires no membranes or solid ion exchangers. Theoretical energy efficiency of this method is on par with electrodialysis and reverse osmosis.

Other applications

In soil science, cation exchange capacity is the ion exchange capacity of soil for positively charged ions. Soils can be considered as natural weak cation exchangers.
In pollution remediation and geotechnical engineering, ion exchange capacity determines the swelling capacity of swelling or Expansive clay such as Montmorillonite, which can be used to "capture" pollutants and charged ions.
In planar waveguide manufacturing, ion exchange is used to create the guiding layer of higher index of refraction.
Dealkalization, removal of alkali ions from a glass surface.
Chemically strengthened glass, produced by exchanging K⁺ for Na⁺ in soda glass surfaces using KNO₃ melts.

Regeneration wastewater

Most ion exchange systems are containers of ion exchange resin operated on a cyclic basis. Water flows through the resin container until the resin is considered exhausted when water leaving the exchanger contains more than the desired maximum concentration of the ions being removed. Resin is then regenerated by sequentially backwashing the resin bed to remove accumulated solids, flushing removed ions from the resin with a concentrated solution of replacement ions, and rinsing the flushing solution from the resin. Production of backwash, flushing, and rinsing wastewater during regeneration of ion exchange media limits the usefulness of ion exchange for wastewater treatment.^[3]

Water softeners are regenerated with brine containing ten percent sodium chloride.^[4] Aside from the soluble chloride salts of divalent cations removed from the softened water, softener regeneration wastewater contains the unused fifty to seventy percent of the sodium chloride regeneration flushing brine required to reverse ion exchange resin equilibria. Deionizing resin regeneration with sulfuric acid and sodium hydroxide is approximately twenty to forty percent efficient. Neutralized deionizer regeneration wastewater contains all of the removed ions plus 2.5 to five times their equivalent concentration as sodium sulfate.^[5]

References

^ Mischissin, Stephen G. (7 February 2012). "University of Rochester - Investigation of Steam Turbine Extraction Line Failures" (PDF). Arlington, VA. p. 25-26. Retrieved 23 February 2015.
^ Shkolnikov, Viktor; Bahga, Supreet S.; Santiago, Juan G. (August 28, 2012). "Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation" (PDF) 14 (32). Phys. Chem. Chem Phys.
^ Kemmer, pp.12-7&12-25
^ Betz, p.59
^ Kemmer, p.12-8

Betz Laboratories (1976). Handbook of Industrial Water Conditioning (7th Edition). Betz Laboratories.
Ion Exchangers (K. Dorfner, ed.), Walter de Gruyter, Berlin, 1991.
C. E. Harland, Ion exchange: Theory and Practice, The Royal Society of Chemistry, Cambridge, 1994.
Friedrich G. Helfferich (1962). Ion Exchange. Courier Dover Publications. ISBN 978-0-486-68784-1.
Kemmer, Frank N. (1979). The NALCO Water Handbook. McGraw-Hill.
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
A simple explanation of deionization
Ion exchange, BioMineWiki

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English Journal

Sodium zirconium cyclosilicate in hyperkalemia.

Packham DK1, Rasmussen HS, Lavin PT, El-Shahawy MA, Roger SD, Block G, Qunibi W, Pergola P, Singh B.
The New England journal of medicine.N Engl J Med.2015 Jan 15;372(3):222-31. doi: 10.1056/NEJMoa1411487. Epub 2014 Nov 21.
BACKGROUND: Hyperkalemia (serum potassium level, >5.0 mmol per liter) is associated with increased mortality among patients with heart failure, chronic kidney disease, or diabetes. We investigated whether sodium zirconium cyclosilicate (ZS-9), a novel selective cation exchanger, could lower serum
PMID 25415807

Cation exchange properties of zeolites in hyper alkaline aqueous media.

Van Tendeloo L, de Blochouse B, Dom D, Vancluysen J, Snellings R, Martens JA, Kirschhock CE, Maes A, Breynaert E.
Environmental science & technology.Environ Sci Technol.2015 Jan 8. [Epub ahead of print]
Construction of multi-barrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchan
PMID 25569300

Chabazite: a stable cation-exchanger in hyper alkaline concrete pore water.

Van Tendeloo L, Wangermez W, Kurttepeli M, de Blochouse B, Bals S, Van Tendeloo G, Martens JA, Maes A, Kirschhock CE, Breynaert E.
Environmental science & technology.Environ Sci Technol.2015 Jan 8. [Epub ahead of print]
To avoid impact on the environment, facilities for permanent disposal of hazardous waste adopt multi-barrier design schemes. As the primary barrier very often consists of cement-based materials, two distinct aspects are essential for the selection of a suitable complementary barriers: 1) selective s
PMID 25569179

Japanese Journal

Chondroitin Sulfate Modified Stationary Phase with Mixed Mode of Hydrophilic Interaction and Strong Cation-Exchange for Capillary Electrochromatography

FUJITA Yoshiko,OHYAMA Kaname,KISHIKAWA Naoya,KURODA Naotaka
CHROMATOGRAPHY advpub(0), 2015
… The sulfonic acid groups on the ChS-silica supported electroosmotic flow at low pH and served as a strong cation-exchanger. … Analytes are likely retained on ChS-silica by hydrophilic interactions (HI) and strong cation-exchange; …
NAID 130005088604

放射能除染排水中のセシウム除去技術の開発に関する基礎的研究

佐野誠,中川清晴,小田廣和 [他],小幡斉,木谷伸二,山崎憲治
化学工学論文集 40(3), 261-265, 2014
放射能除染排水からCsの除去技術の開発を目的として，無機系凝集剤とイオン交換能を持つゼオライトやプルシアン・ブルーとを組み合わせた混合剤を用いた排水中のCsを一段で効果的にイオン交換・凝集沈殿除去する方法を提案した．無機系凝集剤やゼオライト，プルシアン・ブルーの単独およびプルシアン・ブルーを混合剤として用い，それらのCs除去特性について検討した．
NAID 130004855787

Determination of Trace Iron in the Boiler Water Used in Power Generation Plants by Solid-phase Spectrophotometry

SARENQIQIGE,MAEDA Akihiro,YOSHIMURA Kazuhisa
Analytical Sciences 30(10), 1013-1017, 2014
… The reagents and 0.08 cm3 of a cation exchanger were added to a 50-cm3 boiler water sample, then mixed for 30 min to adsorb/concentrate the produced Fe(TPTZ)22+ colored complex on the solid beads, resulting in a 625 times concentration of the target analyte without any other procedure. …
NAID 130004694050