Ethylenediaminetetraacetic acid

Ethylenediaminetetraacetic acid (EDTA) is a white odorless crystalline powder used as chelating agent in pulp & paper, cleaning, chemical processing, agriculture and water treatment.

Acid EDTA also known as edetic acid, is an aminopolycarboxylic acid with the formula [CH2N(CH2CO2H)2]2. This white, water-soluble solid is widely used to bind to iron (Fe2 /Fe3 ) and calcium ions (Ca2 ), forming water-soluble complexes even at neutral pH. It is thus used to dissolve Fe- and Ca-containing scale as well as to deliver iron ions under conditions where its oxides are insoluble.

In Textiles and paper industry, EDTA is mainly used to sequester (bind or confine) metal ions in aqueous solution. In the textile industry, it prevents metal ion impurities from modifying colors of dyed products. In the pulp and paper industry, EDTA inhibits the ability of metal ions, especially Mn2 , from catalyzing the disproportionation of hydrogen peroxide, which is used in bleaching.

In a similar manner, EDTA is added to some food as a preservative or stabilizer to prevent catalytic oxidative discoloration, which is catalyzed by metal ions.

EDTA can solubilize Fe3 ions at or below near neutral pH. This property is useful in agriculture including hydroponics. However, given the pH dependence of ligand formation, EDTA is not helpful for improving iron solubility in above neutral soils. Otherwise, at near-neutral pH and above, iron(III) forms insoluble salts, which are less bioavailable to susceptible plant species.

EDTA is used extensively in the analysis of blood. It is an anticoagulant for blood samples for CBC/FBCs, where the EDTA chelates the calcium present in the blood specimen, arresting the coagulation process and preserving blood cell morphology.

In shampoos, cleaners, and other personal care products, EDTA salts are used as a sequestering agent to improve their stability in air.

CAS #: 60-00-4

Appearance and odor: White odorless crystalline

Molecular Weight: 292.25

Chemical Formula: C10H16O8N2