Natural water does not exist as a chemically pure substance. It contains dissolved minerals, salts and organic compounds and also disperse and colloid disperse substances, furthermore gases, in varying concentrations and compositions.

Ions

Salts dissociate in water and form ions: Positively-charged ions are designated as cations, and negatively-charged ions are anions. Water mainly contains different proportions of the following ions, depending on the source of the water:



Organic

All water also contains organic components with a non-ionic and ionic (mainly anionic) character.

Applications

The selection of an ion exchange process and the degree of demineralisation depend on the application in question and the additional operating and economical conditions.

Description of process

Ion exchangers are synthetic resins (organic polymers). Various exchange-active groups, at which ions accumulate, are built into the exchangers.  In the exchange process, the ions of the solution to be treated are exchanged with accumulated ions with the same electrical charge on the resin.

Principle of ion exchange

Basically, a differentiation is made between cation and anion exchangers.

These types are further differentiated regarding the exchange-active groups:

• Weak acidic / strong acidic
• Weak basic / medium basic / strong basic

Floating bed process

Due to its many advantages, the floating bed method is mostly used for ion exchange systems.
Advantages:

• Extremely effective regenerant use combined
  with optimum demineralisation performance
• Maximum variability in the resin selection
• Low inherent water consumption
• Very compact tank design