EDTA is the strongest, most versatile, and widely used chelant for controlling metal ions over a broad pH range in aqueous systems. EDTA will not chelate monovalent metal ions such as sodium and potassium, but will chelate most multivalent metal ions (e.g., Fe, Cu, Mn, Ca, Mg, Zn) in a 1:1 molar ratio. The chelation reaction is virtually instantaneous in most cases. Calcium and other alkaline earth metals are most effectively chelated above a pH of 4. EDTA chelates most transition metals below a pH of 12. EDTA is completely miscible with water but is not soluble in organic systems. EDTA is stable under widely varying conditions of temperature, acidity, alkalinity, and the presence of other chemicals.
Controls metals over a broad pH range
The use level of EDTA varies depending upon the degree of hardness and application. Typical use levels range from 0.1 - 2.0 g/L.