Which device removes charged impurities using a bed of resin?

• A. Water Purifiers
• B. Filtration Units
• C. Ion Exchangers
• D. Desalination Columns

Answer: (C)

Ion exchange uses a bed of resin with fixed charged groups to remove dissolved ions. When water containing charged impurities flows through the resin, each impurity ion is swapped with a counter ion attached to the resin. This exchange pulls out the unwanted ions and replaces them with stable ions from the resin, effectively deionizing or softening the water. The resin bed provides a large number of exchange sites, so it can remove many ions before it needs regeneration. When the resin becomes saturated with impurities, it’s regenerated with an appropriate solution to restore the original ions on the resin for reuse.