Ion exchange resins used in softening, anion or deionization applications are designed to remove certain ionized substances from water. The resin beads typically range in size from 16 to 50 mesh (1.2 to 0.3 mm) and although they are designed for the removal of dissolved ions, they can become a very effective filter media.
In some specialty applications (e.g., condensate polishing) resins are used as much for their filtration properties as for their ion exchange characteristics. For the most part, however, it is a good idea to keep the resin bed free of suspended particles.
Cleaning and prevention to avoid fouling
Arsenic and uranium in drinking water supplies
In January 2006, the U.S. Environmental Protection Agency started enforcing the new arsenic limit of 10 parts per billion (ppb) in drinking water. The previous limit was 50 ppb. Since that date, there has been a flurry of activity in bringing selective arsenic media to the market.
Effective arsenic removal applications for water treatment
All raw water supplies contain dissolved ions that are positively or negatively charged. The positively charged ions (called cations) include calcium and magnesium, which constitute hardness. Other cations present in water are sodium, potassium and iron. The negatively charged ions in water (called anions) include sulfates, chlorides, bicarbonates and silica.
Ion exchange for removal of groundwater contaminants