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Ion Exchange Reactions

Ion exchange is a reversible chemical reaction where an ion (an atom or molecule that has lost or gained

an electron and thus acquired an electrical charge) from solution is exchanged for a similarly charged ion

attached to an immobile solid particle. These solid ion exchange particles are either naturally occurring

inorganic zeolites or synthetically produced organic resins. The synthetic organic resins are the

predominant type used today because their characteristics can be tailored to specific applications.

An organic ion exchange resin is composed of high-molecular-weight polyelectrolytes that can exchange

their mobile ions for ions of similar charge from the surrounding medium. Each resin has a distinct

number of mobile ion sites that set the maximum quantity of exchanges per unit of resin.

Most plating process water is used to cleanse the surface of the parts after each process bath. To

maintain quality standards, the level of dissolved solids in the rinse water must be regulated. Fresh water

added to the rinse tank accomplishes this purpose, and the overflow water is treated to remove

pollutants and then discharged. As the metal salts, acids, and bases used in metal finishing are primarily

inorganic compounds, they are ionized in water and can be removed by contact with ion exchange

resins. In a water deionization process, the resins exchange hydrogen ions (H+) for the positively charged

ions (such as nickel. copper, and sodium). and hydroxyl ions (OH-) for negatively charged sulfates,

chromates. and chlorides. Because the quantity of H+ and OH ions is balanced, the result of the ion

exchange treatment is relatively pure, neutral water.

Ion exchange is the reversible interchange of ions between a solid (the ion exchange resin) and

a liquid. Since they act as "chemical sponges", ion exchange resins are ideally suited for

effective removal of contaminants from water and other liquids. This technology offers a number

of advantages in industrial water demineralization and softening, wastewater recycling and other

water treatment processes-including high water recovery, low volume of waste and operational

flexibility. Ion exchange resins are also used in a variety of specialized applications such as

chemical processing, pharmaceuticals, mining, and food and beverage processing. DOWEX

and AMBERJET are among the world's leading brands of ion exchange resin technology,

backed by Dow's more than 60 years of experience in this area.

http://www.dowwaterandprocess.com/products/ion_exchange.htm

on exchange is 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.

Most typical example of application is preparation of high purity water forpower engineering,

electronic and nuclear industries; i.e.polymericormineralicinsolubleion exchangers are widely

used forwater softening,water purification, waterdecontamination, etc.

Ion exchange is a method widely used in household (laundry detergentsandwater filters) to

producesoft water. This is accomplished by

exchangingcalciumCa2+

andmagnesiumMg2+

cations against Na+

or H+

cations (seewater

softening).

Industrial and analyticalion exchange chromatographyis another area to be mentioned.Ion

exchange chromatographyis achromatographicalmethod that is widely used for chemical

analysis and separation of ions. For example, inbiochemistryit is widely used to separate

charged molecules such asproteins. An important area of the application is extraction and

purification of biologically produced substances such as proteins (amino acids) andDNA/RNA.

Ion-exchange processes are used to separate and purify metals, including

separatinguraniumfromplutoniumand otheractinides, includingthorium,

andlanthanum,neodymium,ytterbium,samarium,lutetium, from each other and the

otherlanthanides. There are two series ofrare earthmetals, the lanthanides and the actinides,

both of whose families all have very similar chemical and physical properties. Using methods

developed byFrank Speddingin 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 thePUREXprocess (plutonium-uranium extraction process), which is

used to separate theplutoniumand theuraniumfrom the spent fuel products from anuclear

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 aszirconiumandhafnium, 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 reactorcontrol rods.

Ion exchangers are used innuclear reprocessingand the treatment ofradioactive waste.

Ion exchange resins in the form of thinmembranesare used inchloralkali process,fuel

cellsandvanadium redox batteries. 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.

http://www.dowwaterandprocess.com/products/ion_exchange.htmhttp://www.dowwaterandprocess.com/products/ion_exchange.htmhttp://en.wikipedia.org/wiki/Power_engineeringhttp://en.wikipedia.org/wiki/Power_engineeringhttp://en.wikipedia.org/wiki/Power_engineeringhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_purificationhttp://en.wikipedia.org/wiki/Water_purificationhttp://en.wikipedia.org/wiki/Water_purificationhttp://en.wikipedia.org/wiki/Decontaminationhttp://en.wikipedia.org/wiki/Decontaminationhttp://en.wikipedia.org/wiki/Decontaminationhttp://en.wikipedia.org/wiki/Laundry_detergenthttp://en.wikipedia.org/wiki/Laundry_detergenthttp://en.wikipedia.org/wiki/Laundry_detergenthttp://en.wikipedia.org/wiki/Filter_(water)http://en.wikipedia.org/wiki/Filter_(water)http://en.wikipedia.org/wiki/Filter_(water)http://en.wikipedia.org/wiki/Soft_waterhttp://en.wikipedia.org/wiki/Soft_waterhttp://en.wikipedia.org/wiki/Soft_waterhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Chromatographyhttp://en.wikipedia.org/wiki/Chromatographyhttp://en.wikipedia.org/wiki/Chromatographyhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Amino_acidshttp://en.wikipedia.org/wiki/Amino_acidshttp://en.wikipedia.org/wiki/Amino_acidshttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Actinidehttp://en.wikipedia.org/wiki/Actinidehttp://en.wikipedia.org/wiki/Actinidehttp://en.wikipedia.org/wiki/Thoriumhttp://en.wikipedia.org/wiki/Thoriumhttp://en.wikipedia.org/wiki/Thoriumhttp://en.wikipedia.org/wiki/Lanthanumhttp://en.wikipedia.org/wiki/Lanthanumhttp://en.wikipedia.org/wiki/Lanthanumhttp://en.wikipedia.org/wiki/Neodymiumhttp://en.wikipedia.org/wiki/Neodymiumhttp://en.wikipedia.org/wiki/Neodymiumhttp://en.wikipedia.org/wiki/Ytterbiumhttp://en.wikipedia.org/wiki/Ytterbiumhttp://en.wikipedia.org/wiki/Samariumhttp://en.wikipedia.org/wiki/Samariumhttp://en.wikipedia.org/wiki/Samariumhttp://en.wikipedia.org/wiki/Lutetiumhttp://en.wikipedia.org/wiki/Lutetiumhttp://en.wikipedia.org/wiki/Lutetiumhttp://en.wikipedia.org/wiki/Lanthanidehttp://en.wikipedia.org/wiki/Lanthanidehttp://en.wikipedia.org/wiki/Lanthanidehttp://en.wikipedia.org/wiki/Rare_earth_elementhttp://en.wikipedia.org/wiki/Rare_earth_elementhttp://en.wikipedia.org/wiki/Rare_earth_elementhttp://en.wikipedia.org/wiki/Frank_Speddinghttp://en.wikipedia.org/wiki/Frank_Speddinghttp://en.wikipedia.org/wiki/Frank_Speddinghttp://en.wikipedia.org/wiki/PUREXhttp://en.wikipedia.org/wiki/PUREXhttp://en.wikipedia.org/wiki/PUREXhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_weaponhttp://en.wikipedia.org/wiki/Nuclear_weaponhttp://en.wikipedia.org/wiki/Nuclear_weaponhttp://en.wikipedia.org/wiki/Zirconiumhttp://en.wikipedia.org/wiki/Zirconiumhttp://en.wikipedia.org/wiki/Zirconiumhttp://en.wikipedia.org/wiki/Hafniumhttp://en.wikipedia.org/wiki/Hafniumhttp://en.wikipedia.org/wiki/Hafniumhttp://en.wikipedia.org/wiki/Control_rodhttp://en.wikipedia.org/wiki/Control_rodhttp://en.wikipedia.org/wiki/Control_rodhttp://en.wikipedia.org/wiki/Nuclear_reprocessinghttp://en.wikipedia.org/wiki/Nuclear_reprocessinghttp://en.wikipedia.org/wiki/Nuclear_reprocessinghttp://en.wikipedia.org/wiki/Radioactive_wastehttp://en.wikipedia.org/wiki/Radioactive_wastehttp://en.wikipedia.org/wiki/Radioactive_wastehttp://en.wikipedia.org/wiki/Proton_exchange_membranehttp://en.wikipedia.org/wiki/Proton_exchange_membranehttp://en.wikipedia.org/wiki/Proton_exchange_membranehttp://en.wikipedia.org/wiki/Chloralkali_processhttp://en.wikipedia.org/wiki/Chloralkali_processhttp://en.wikipedia.org/wiki/Chloralkali_processhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Vanadium_redox_batteryhttp://en.wikipedia.org/wiki/Vanadium_redox_batteryhttp://en.wikipedia.org/wiki/Vanadium_redox_batteryhttp://en.wikipedia.org/wiki/Vanadium_redox_batteryhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Chloralkali_processhttp://en.wikipedia.org/wiki/Proton_exchange_membranehttp://en.wikipedia.org/wiki/Radioactive_wastehttp://en.wikipedia.org/wiki/Nuclear_reprocessinghttp://en.wikipedia.org/wiki/Control_rodhttp://en.wikipedia.org/wiki/Hafniumhttp://en.wikipedia.org/wiki/Zirconiumhttp://en.wikipedia.org/wiki/Nuclear_weaponhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/PUREXhttp://en.wikipedia.org/wiki/Frank_Speddinghttp://en.wikipedia.org/wiki/Rare_earth_elementhttp://en.wikipedia.org/wiki/Lanthanidehttp://en.wikipedia.org/wiki/Lutetiumhttp://en.wikipedia.org/wiki/Samariumhttp://en.wikipedia.org/wiki/Ytterbiumhttp://en.wikipedia.org/wiki/Neodymiumhttp://en.wikipedia.org/wiki/Lanthanumhttp://en.wikipedia.org/wiki/Thoriumhttp://en.wikipedia.org/wiki/Actinidehttp://en.wikipedia.org/wiki/Plutoniumhttp://en.wikipedia.org/wiki/Uraniumhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/Amino_acidshttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Ion_exchange_chromatographyhttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Soft_waterhttp://en.wikipedia.org/wiki/Filter_(water)http://en.wikipedia.org/wiki/Laundry_detergenthttp://en.wikipedia.org/wiki/Decontaminationhttp://en.wikipedia.org/wiki/Water_purificationhttp://en.wikipedia.org/wiki/Water_softeninghttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Power_engineeringhttp://www.dowwaterandprocess.com/products/ion_exchange.htm