Mixed bed Ion Exchanger

Mixed bed is better than using first one ion exchange resin to remove cations and then another to remove anions because having both resins in very close proximity creates a stronger driving force as the hydrogen ion exchanged at one resin attracts a hydroxyl ion from the other resin to form water. Deionized water is usually an excellent substitute for distilled water and is less expensive. The mixed bed process is conducted in plastic vessels to resist acid corrosion, and faulty balancing of flows during regeneration can generate so much heat from acid reacting with base that steam forms and the plasitic melts, but with proper flow adjustments and automation, mixed bed ion exchange is quite reliable.

Mixed bed resins or mixed bed ion exchange resins are mainly used in the water purification industry for polishing process water to achieve demineralized water quality (such as after a reverse osmosis system). Mixed bed as the name states consists of strong acid cation exchange and strong base anion exchange resin. Typical applications include:

In a mixed bed ion exchange column, cation and anion resins are adjacent through mixture. In H-OH form the cation resin contains exchangeable H+ ions and anion resin contains exchangeable OHions. Consequently, even better purification is obtained than with the application of an alternating sequence of cation and anion exchangers because exchanges are coupled by water dissociation equilibrium of the H+ and OHions to water. Hence, a mixed bed ion exchange column represents a powerful single unit for demineralizing water; and with refinement, produces water of utmost purity.

• Ultra pure water production
• Demineralisation
• Condensate polishing (boiler feed water)
• Micro electronics cleaning
• Pharmaceuticals