Polyaminocarboxylic acids and their salts made from ethylene amines are used in a variety of applications to control the level or activity of metal ions so that they cannot cause rust spots or staining and catalyze unwanted chemical reactions, such as oxidation reactions. It is also used to control water hardness. The most known Chelating Agents are EDTA (Ethylenediamine tetraacetic acid) and their sodium salts and DTPA (Diethylenetriaminepenta acetic acid).
Chelating agents are applied in:
- industrial cleaners (for descaling and derusting of equipment)
- detergents (prevent metal staining, and premature decomposition of bleaching agents)
- food industry (flavour retention, retard rancidity, prevents oxidation and discoloration)
- metal treatment (removal and prevention of scale)
- paper industry (pretreatment of the washing liquor in chemical pulp bleaching)
- photography (in rinsing baths and leach-fixing baths)
- polymer processing (removal of trace impurities in production of PVC stabilization of latex emulsions, polymers and rubber)
- textile processing (for the removal of heavy metal ions during scouring and bleaching or stabilization of dye-baths)
- agriculture (as metal carriers in micronutrients for correcting trace metal deficiencies in animals and also plants and trees).