Deionization is a very convenient and cost effective water filtration process for producing highly purified water on demand for aquarium or hydroponic use.
As long as most non particulate water impurities are dissolved salts, compared to distillation deionization is much faster. Basically more cost effective, deionization produces high purity water that is generally similar to distilled water.
Undoubtedly it’s an ondemand process that supplies a lot of highly purified water as needed. By definition, deionization, often called DI for short, is the removal of all ionized minerals and salts from water through the process of ion exchange. Anyway, while producing a more purified water, Much like a positively charge magnet will attract a negatively charged magnet, DI resins attract ‘nonwater’ ions and replace them with water ions. Whenever controlling the electric charge of ions in the water to remove the TDS, Deionization removes total dissolved solids from water using ion exchange resins.
The deionization process uses two resins that have opposite charges -the cationic and the anionic.
The hydrogen and hydroxide ions therefore combine to form water.
This resin attracts the positively charged ions in the water and releases an equivalent percentage of hydrogen ions. It is ‘precharged’ with hydroxide ions. Consequently, cationic resin contains negatively charged sulfonic acid groups, precharged with hydrogen ions. It is this resin attracts negatively charged ions and releases an equivalent percentage of hydroxide.
Eventually, anionic resin contains positively charged ammonium groups. The best DI resin to use is the color changing mixed bed type that changes color from blue/green to amber as the resin is exhausted. Notice that if you’re not using DI resin in your reverse osmosis system it’s a good idea to be. Now let me tell you something. The lifespan of a DI filter cartridge can vary greatly with the quality of the supply water used and the RO system configuration. For instance, carbon block cartridge or membrane cartridge are in need of replacement, they are not filtering properly, and more TDS are being sent to the DI cartridge which will exhaust the resin more quickly, if the RO system pre filter sediment cartridge.
Over time positive and negative contaminants in the water displace the active hydrogen and hydroxyl molecules in the ion exchange resin and the resin loses its ability to remove contaminants, it becomes exhausted.