This typical process involves the removal of Cations (e.g. Calcium, Magnesium, Sodium, Potassium, Iron and other heavy metals) by a bed of Purolite^® Strong Acid Cation (SAC) ion exchange resin followed by a second bed of Purolite Strong Base Anion (SBA) resin for the removal of all anions (e.g. Bicarbonate Alkalinity, Chloride, Sulfate, Nitrate, Silica and CO2) or a second bed of Purolite Weak Base Anion (WBA) resin for the removal Strong Acid Anions (e.g. Chloride, Sulfate and Nitrate).

The Purolite SAC bed is regenerated with HCl or H₂SO₄. The Purolite Anion bed is regenerated with NaOH. In the Purolite SAC bed the cations removed from the water are replaced with the Hydrogen ion, while in the Purolite SBA bed the removed ions are replaced with the OH^- ion. If a Purolite WBA bed is used it will be in the Free Base Form, the process being to absorb entire Strong Acid Anion molecules. The resulting effluent, therefore, is H plus OH, or H₂O. The effluent quality resulting will depend upon feedwater quality, regeneration procedures, age of the resins and the quality of the regenerants.

With a Purolite SBA resin, Silica and CO₂ are also removed. With a Purolite WBA resin Silica and CO₂ are not removed.

Typical Two Bed Purolite^® SBA demineralisation systems will produce a minimum 50,000 ohms specific resistance (20 micromhos conductivity - 10 ppm TDS as CaCO₃) endpoint. It is not unusual to obtain water quality in excess of 500,000 ohms specific resistance (2 micromhos conductivity - 1 ppm TDS as CaCO₃) .
Typical Two Bed Purolite WBA systems will produce a minimum of 20,000 ohms specific resistance (50 micromhos conductivity - 25 ppm TDS as CaCO₃) endpoint. It is not unusual to obtain water quality in excess of 100,000 ohms specific resistance (10 micromhos conductivity - 5 ppm TDS as CaCO₃).

The Deionisation process is also known as Demineralisation.

Some factors that affect the performance of resins used in Deionisation are:

• Chlorine Content.
• TDS.
• WaterTemperature.
• Silica content.
• Carbon Dioxide content.
• Irreversible fouling.
• Organics content
• Flow rates

Typical Purolite^® resin choices for Deionization include:

• Purolite Strong Acid Cations:
  C100H
  C150H
  C100x10H
• Purolite Strong Base Anions:
  A300
  A400
  A500
  A510
  A555
  A850
• Purolite Weak Base Anions:
  A100
  A847