Effective ion exchange for challenging water-treatment needs

Ion exchange technology is a proven method of producing high purity softened and demineralized water. It is used in most industries that require high purity water and to reclaim water from processes. The Ion exchange process involves the exchanging of contaminant ions for Na+ ions in a softening application and H+ and OH- ions in pure water application. Veolia offers a range of ion exchange products for applications, including condensate and brine polishing, vacuum degassing, and desalination. 

Cation, anion, chelating, and adsorbents

Ion exchange resins are identified by the functional group to which they belong. Resins are conventionally classified as:

    ● Cation exchange resins

      ◆ Strong acid (SAC): Characterized by their ability to exchange cations or split neutral salts; they are useful across the entire pH range.

      ◆ Weak acid (WAC): Have a high affinity for the hydrogen ion and are therefore easily regenerated with strong acids; they exhibit a high capacity for the alkaline earth metals associated with alkalinity and a more limited capacity for the alkali metals.

    ● Anion exchange resins

      ◆ Strong base (SBA)

         ◉ Type 1: The most strongly basic functional group available with the greatest affinity for the weak acids such as silicic acid and carbonic acid that are commonly present during a water demineralization process; the efficiency of regeneration of the resin to the hydroxide form is somewhat lower than Type 2.

         ◉ Type 2: Has lower basicity than that of the Type 1 resin, yet it is high enough to remove the weak acidanions for most applications; the chemical stabilityis not as good as that of the Type 1 resins, which are favored for high temperature applications; regeneration efficiency of a Type 2 resin is considerably greater than that of Type 1.

      ◆ Weak base (WBA): Contain tertiary amine functionalities, which act as acid adsorbers; capable of sorbing strong acids with a high capacity and are readily regenerated with caustic; particularly effective when used in combination with a strong base anion by providing an overall high operating capacity and regeneration efficiency.

    ● Special chemical groups, such as chelating resins for the hydrometallurgical industry that are particularly applicable for the selective exchange of various heavy metals from alkaline earth and alkali metal solutions.

    ● Adsorbents: Used for organic compound removal in many industries, such as bioprocessing and applications such as wastewater treatment.