Deionizers are important pieces of equipment that remove dissolved ionic salts and minerals from a solution using an ion exchange process. They are also known as ion exchangers, demineralizers, or DI systems.Applications for deionizers include waste water processing, potable water creation on marine vessels, and pure water creation for sensitive processes such as nuclear power generation, semiconductor manufacturing and pharmaceuticals. They are often used with systems used to treat brackish or sea water such as reverse osmosis systems.
Deionizers consist of one or more deionization cartridges that are connected to a water supply. Deionization is the process of exchanging the contaminant cations with hydrogen and contaminant anions with hydroxyl ions, respectively. Deionizer cartridges contain a specific resin of tiny beads. When the water passes through the resin, the impurities are replaced by free hydrogen and hydroxyl groups (H+ and OH-) which are nothing more than the components that make up water. The resin within the deionizer has a limited number of areas for the ion exchange to occur. For this reason deionizers are not used to treat highly contaminated water directly as it would use up the resin very quickly. Once all the ion exchange areas have been filled with anion and cation contaminates the resin can no longer be used until it is replaced or recharged by washing in diluted hydrochloric acid for the cation resin and sodium hydroxide for the anion resin.
There are two main types of deionizers.
Mixed Bed: Mixed bed deionizers will have both anion and cation resins in the same housing so both types of contaminants are replaced at the same time. This combination usually results in larger housings.
Multiple Bed: Multiple bed deionizers will have separate housing for each type of resin. This can provide options for mounting or piping when space is at a premium. Also can allow recharging of both resins at once.
Deionizer housings are commonly made of metal or plastic, and the ion exchange resin is polymer based. Deionizers will vary in shape and size depending on application and can be mounted as a stationary unit or on a movable platform cart.
Specifications and Features
The follow specifications determine the functionality of a deionizer.
- Continuous Flow Rate: The continuous flow rate of liquid flow through the deionizer while maintaining proper efficiency.
- Removal Application: The removal application will determine how and where the deionizer can be used.
This feature provides additional utility or ease-of-use.
Automatic Control System: A deionizer with an automatic control system can control inlet outlet and bypass valves as well as provide remote indication if there is a problem needing operator attention.
AXEON Water Technologies | Eco-Tec, Inc. | Sartorius Group