Reverse Deionization

the use of the anion exchange resin ahead of the cation exchange resin in a deionization system.

Definitioner

Resin: synthetic organic ion exchange material, such as the high capacity exchange resin widely used in water softeners.
Deionization: the removal of all ionized minerals and salts (both organic and inorganic) from a solution by a two stage ion exchange procedure. First, positively charged for a chemically equivalent amount of hydrogen ions. Second, negatively charged ions are removed by an ion exchange resin for a chemically equivalent amount of hydroxide ions. The hydrogen and hydroxide ions are introduced in this process unite to form water molecules. The term is often used interchangeably with demineralization.
Cation Exchange: process in which cations in solution are exchanged for other cations from an ion exchanger.
Cation: an ion with a positive electrical charge, such as calcium, magnesium and sodium.
Anion Exchange: An ion exchange process in which anions in solution are exchanged for other anions for an ion exchanger. In demineralization, for example, bicarbonate, chloride and sulfate anions are removed from solution in exchange for a chemically equivalent number hydroxide anions from the anion exchange resin.
Anion: A negatively charged ion in solution, such as bicarbonate, chloride, or sulfate.