ion exchange

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Related to Cation exchanger: Cation exchange resin, Anion exchanger

ion exchange

the process in which ions are exchanged between a solution and an insoluble solid, usually a resin. It is used to soften water, to separate radioactive isotopes, and to purify certain industrial chemicals

Ion Exchange


the exchange of ions in electrolytic solutions (homogeneous ion exchange). When dilute electrolytic solutions, such as NaCl and KNO3, are mixed, Na+, K+, NO3, and Cl ions are present in the mixture. The state of equilibrium for this case is expressed by the equation NaCl + KNO3 ⇄ NaNO3 + KCl (double-exchange reaction). If one of the substances produced during the interaction is less dissociated than the others, the equilibrium shifts toward the formation of the poorly dissociated substance. The equilibrium also shifts toward the formation of a volatile or poorly soluble product (if it is precipitated from the particular phase) according to the reactions

H2SO4 + 2KCN ⇄ K2SO4 + 2HCN ↑

NaCl + AgNO3 ⇄ NaNO3 + AgCl↓ I

The crystallization of a salt (ion combination), which has lower solubility, is the first process to take place upon evaporation of an equilibrium solution. The selectivity of crystallization may also be caused by the addition of organic solvents, such as alcohol, acetone, or dioxane.

During heterogeneous ion exchange (ion-exchange sorption), exchange takes place between ions that are in solution and those that are on the surface of the solid phase (the ion exchanger). When an ion exchanger saturated with one ion (such as H+) comes into contact with a solution containing other ions (for example, Na+ and Ca2+), ion exchange occurs between the ion exchanger and the solution: the concentration of Na+ and Ca2+ in the solution is reduced, and an equivalent quantity of H+ ions appears.

Heterogeneous ion exchange takes place during sorption of certain minerals (aluminosilicates, metallic hydroxides, and zeolites) from electrolytic solutions in the cells and membranes of living organisms and in synthetic ion-exchange sorbents. This type of ion exchange is widely used for the desalinization of water used to feed high-pressure steam boilers, as well as in hydrometallurgy and the chemical and pharmaceutical industries.


ion exchange

[′ī‚än iks‚chānj]
(physical chemistry)
A chemical reaction in which mobile hydrated ions of a solid are exchanged, equivalent for equivalent, for ions of like charge in solution; the solid has an open, fishnetlike structure, and the mobile ions neutralize the charged, or potentially charged, groups attached to the solid matrix; the solid matrix is termed the ion exchanger.
References in periodicals archive ?
Keywords: Chromium (III) hybrid cation exchangers ion exchange kinetics spent tanning bath thermodynamics.
Table-1: The characteristic properties of hybrid cation exchangers.
ions of the initialized cation exchanger were substituted for other inorganic ions by filling with solutions that contain various ions, and the impedance measurements were carried out.
Z|-f characteristics were measured for cation exchanger treated with solutions with various concentrations of [Ca.
The cation exchangers are especially suited for softening waters of high alkalinity and for recarbonating lime softened water; anion exchangers for removing alkalis.
2]) on both anion and cation exchangers (unless a very slow gradient on a Baker-Bond PEI-WAX column is used).
These pre-validated chromatography columns come packed with either strong cation exchangers, weak cation exchangers or strong anion exchangers, freeing up end users' time and resources by eliminating manual column packing and cleaning.
Cation exchangers remove calcium, magnesium, sodium, and other positive ions, acting like ordinary zeolite; and anion exchangers remove carbonates, bicarbonates, sulfates, chlorides, and other negative ions.
Tenders are invited for Supply of Strong Acid Cation Exchangers (Pressure Vessel) Having 90 M3/Hr Capacity And Their Accessories