Deionized resin, also known as ion exchange resin, is a material widely used in the field of water treatment, and its main role is to remove ions from water and make water more pure. In laboratory ultrapure water systems, deionization resins are mainly used to remove ions, especially cations and anions, from water to produce high-purity water.
The working principle of deionized resins is based on an ion exchange process. This resin is usually found in the form of small particles and has a charged ion exchange site. They can be anion exchange resins or cation exchange resins, depending on their chemical properties. Deionized resins work as follows:
Adsorption: As water passes through a column or bed containing deionized resin, ion exchange sites on the resin particles adsorb ions in the water. Cation exchange resins adsorb positively charged ions, such as calcium and magnesium ionsAnion-exchange resins adsorb negatively charged ions, such as chloride and nitrate.
Desorption: When the exchange site on the resin is occupied by ions in the water, the resin releases ions with the same charge as it. This is why deionized resin is named because it enables ion exchange.
Rinse: Over time, the deionized resin becomes saturated and no longer able to adsorb more ions. At this point, the resin bed needs to be flushed or regenerated, usually with brine (for anion exchange resins) or hydrochloric acid (for cation exchange resins) to remove adsorbed ions and restore the resin's adsorption capacity.
Deionized resins in laboratory ultrapure water systems are often used in combination with other water treatment technologies, such as reverse osmosis (RO) and electrodeionization (EDI), to produce high-purity water. The combination of these technologies can remove almost all impurities from water, including soluble salts, microorganisms, organics, and particulate matter, resulting in ultrapure water that is suitable for a variety of applications, from laboratory research to pharmaceutical production.