Production of Soft or Deionized Water

Water with a lower hardener content than that produced according to the process described in Section 1.1.2.4 is required for a range of industrial processes. This can be accomplished by ion exchange with solid polymeric organic acids, the ion exchangers . 

When the sodium salt of sulfonated poly(styrene) is used as the cation exchanger, calcium and magnesium ions are exchanged for sodium ions  

If ion exchangers are used in the acid form, then the eluant will be acidic  

Water with less than 0.02 mg/L can be obtained by stepwise treatment over cation and anion exchange beds or in mixed beds . Residual organic impurities can be removed by reverse osmosis 

Basic ion exchangers remove anions and are regenerated with sodium hydroxide, e.g. 

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