Method of partial demineralization of waters by combining weak acid and basic ion-exchanger material and following ion-exchanger material regeneration

摘要

A process for the partial desalination of water consists in a combination of weakly acidic cation exchangers in free acid form in aqueous suspensions and basic anion exchangers in hydrogen carbonate form and subsequent regeneration of the loaded ion exchange material, the required or desired limit values for the salt concentrations for drinking water being undershot and during regeneration Adequate capacity recovery for the weakly acidic cation exchanger and the basic anion exchanger is achieved with the least possible effort in an economically justifiable regeneration period. In this way, partial desalination of groundwater with a slightly alkaline pH value can be achieved. For this purpose, a) partial desalination is carried out with a combination or mixture of weakly acidic cation exchangers and strongly basic anion exchangers with a pK 5, b) depending on the combination or mixing ratio of the two exchangers according to a) non-equivalent amounts of Neutral salt cations and anions are removed from the water, c) the regeneration of both exchangers is carried out together using CO2 only.