Food grade EDTA ferric sodium salt CAS 15708-41-5/149022-26-4

 What is EDTA Iron(III) Sodium Salt?

EDTA Iron(III) Sodium Salt, also known as sodium ethylenediaminetetraacetic acid (often abbreviated as EDTA iron sodium, NaFeEDTA, EDTA-Fe, or sodium edetate iron), is a sodium salt of a chelate formed by ferric ions (Fe³⁺) and ethylenediaminetetraacetic acid (EDTA). It is commonly available in trihydrate form, with the chemical formula:

C10H12FeN2O8Na·3H2O

EDTA iron sodium is typically a light yellowish-brown to brownish-brown powder, readily soluble in water, and its aqueous solution is weakly acidic. It is also a photosensitive substance—under strong light, the Fe³⁺ in EDTA iron sodium undergoes a photoreduction reaction to form Fe²⁺, which dissociates from the EDTA chelate and may further oxidize and precipitate. Therefore, EDTA iron sodium products need to be stored in the dark.

EDTA Iron(III) Sodium Salt?

EDTA sodium iron is widely known for its outstanding performance as an iron fortifier in the food industry—its resistance to phytic acid, high absorption, and minimal impact on food sensory characteristics (see the food-grade applications blog for details). However, in the three non-food sectors of agriculture and animal feed, EDTA sodium iron also plays a crucial role in "maintaining iron availability in environments where iron would otherwise be ineffective." From correcting iron deficiency chlorosis in crops in calcareous soils to providing absorbable iron sources for newborn piglets, from highly effective iron supplements in oral iron medications to the removal of heavy metals from industrial wastewater—the non-food value of EDTA sodium iron also revolves around the tightly bound chemical bond between iron ions and EDTA, with a coefficient of log K ≈ 25.

1. Agricultural grade – Highly efficient chelated iron fertilizer for correcting iron deficiency chlorosis in crops.

This is the largest and most widely distributed application of EDTA iron sodium in the non-food sector. Iron is an essential micronutrient for plants, a catalytic cofactor in chlorophyll synthesis, and a core component of ferredoxin in the photosynthetic electron transport chain. A typical symptom of iron deficiency in plants is interveinal chlorosis and yellowing of new leaves while the veins remain green—because iron has extremely poor mobility within plants, iron in older leaves cannot be transported to new tissues when deficient, and yellowing begins first in new leaves and shoots.

Approximately 30% of the world's arable land suffers from varying degrees of iron deficiency, particularly in the following soil types:

- Calcareous soils (pH 7.5~8.5): Large areas of arable land in the North China Plain, arid Northwest China, and the Mediterranean coast—high pH and high calcium carbonate content cause Fe²⁺ in the soil solution to be rapidly oxidized to Fe³⁺ and precipitated as insoluble ferric hydroxide.

- In saline-alkali soils and soils where phosphate fertilizers have been applied in large quantities for a long time, phosphate ions react with iron to form insoluble iron phosphate precipitates, locking up the iron stores in the soil.

The core value of EDTA iron sodium as a chelated iron fertilizer:

Stability in high pH environments—this is the fundamental advantage of EDTA iron sodium over inorganic iron fertilizers such as ferrous sulfate. Ferrous sulfate (FeSO₄·7H₂O) is the cheapest iron fertilizer, but once dissolved in soil solutions with a pH > 7, Fe²⁺ is almost immediately oxidized and hydrolyzed into insoluble iron oxides—ferrous sulfate applied to the soil can change from "soluble iron that plants can absorb" to "solid rust that cannot be absorbed by roots" within hours, resulting in extremely low fertilizer utilization. The iron ions in EDTA iron sodium are chelated and protected by EDTA with extremely high bond energy, maintaining a stable dissolved state over a wide pH range of 3–9—even in calcareous soil solutions with a pH of 8, the iron in EDTA iron sodium still exists in the form of soluble chelates, which can be directly absorbed by plant roots.

Highly efficient carrier for foliar spraying:

For fruit trees and vegetables that have already shown symptoms of iron deficiency and yellowing, foliar spraying is the fastest way to correct iron deficiency. EDTA iron sodium is highly water-soluble and the solution is stable. After being sprayed on the leaves, it can be directly absorbed and utilized by the leaves through stomata and cuticle, and the yellowed leaves can begin to turn green within a few days. Iron-sensitive, high-value-added crops such as citrus, grapes, strawberries, peaches, peanuts, and soybeans are the main targets for application of EDTA iron sodium foliar fertilizer.

An ideal iron source for fertigation (drip irrigation/micro-sprinkler irrigation):

In modern facility agriculture (greenhouses, hydroponics, drip irrigation orchards), iron must be transported to the crop root zone in a completely dissolved form through the irrigation system. Ferrous sulfate is highly susceptible to oxidation and precipitation in high-pH irrigation water, which can clog drippers and micro-sprinklers. The solution stability of EDTA sodium iron is an irreplaceable operational advantage in this scenario.

Potential crops and application scenarios:

- Citrus, lemon, and other Rutaceae fruit trees (the fruit tree group most severely affected by iron deficiency chlorosis globally)

- Grapes (iron deficiency in calcareous soils leads to poor fruit coloring and low sugar content)

- Berries such as strawberries and blueberries

- Greenhouse vegetables such as tomatoes, peppers, and cucumbers

- Legumes such as peanuts and soybeans (iron is a key component of nitrogenase).

- Iron nutrition for flowers (cut flowers such as roses and lilies in soilless substrate)

- Lawns and golf courses (maintaining aesthetic greenery)

2. Feed grade – a highly efficient organic iron source for animal nutrition.

In animal husbandry, iron deficiency anemia in newborn piglets is a nutritional problem with significant economic impact. Newborn piglets have only about 40-50 mg of iron stored in their bodies, and the iron content in sow's milk is extremely low (about 1 mg/L), while piglets require about 7-15 mg of iron daily for rapid growth. Without exogenous iron supplementation, piglets' iron reserves are depleted within 7-10 days after birth, resulting in stunted growth, pale skin, rapid breathing, and a significant decrease in immunity.

The current standard practice in animal husbandry is to administer iron dextran intramuscularly to piglets within 1-3 days of birth—a single injection of 100-200 mg of iron. While effective, this method presents challenges such as high labor intensity, risk of infection at the injection site, and stress in animals. Oral iron supplementation in feed, as an alternative or supplemental method, faces a core technological bottleneck highly consistent with the oral delivery problems of traditional iron salts—the low absorption efficiency of inorganic iron salts (such as ferrous sulfate) in feed and the animal's gastrointestinal tract.

Advantages of using EDTA iron sodium in feed:

- Chelated iron is chemically stable during feed processing and storage.

- Iron ions are protected by EDTA and do not form insoluble precipitates with other feed ingredients (phytic acid, calcium phosphate, tannins, etc.) in the gastrointestinal tract.

- The absorption efficiency is significantly higher than that of inorganic iron sources such as ferrous sulfate.

- It can be added to the gestation and lactation feeds of sows to indirectly improve the iron nutritional status of piglets by increasing the iron content of sow milk.

- Used in poultry feed to improve broiler growth performance and laying hen egg production performance.

3. Water Treatment and Environmental Remediation – Heavy Metal Removal Based on EDTA Chelation Platform

EDTA iron sodium is highly stable in water and carries a negative charge—a property that subtly shifts its application logic in water treatment and environmental remediation towards "utilizing the chemical properties of chelated iron to treat other metal ions." In environmental chemistry research, EDTA iron sodium has been explored for:

- To maintain Fe²⁺ or Fe³⁺ in solution as a stable EDTA chelate in a dissolved state, serving as a catalyst in certain advanced oxidation processes (such as the Fenton and Photo-Fenton reactions).

- Utilizing the photochemical activity of EDTA iron sodium (Fe³⁺→Fe²⁺ photoreduction under light) as a homogeneous photocatalyst in the photocatalytic degradation of organic pollutants.

- As a competitive chelating agent for heavy metal ions in industrial wastewater, assisting in other metal precipitation or ion exchange processes.

It should be noted that water treatment is not the main production application of EDTA iron sodium—this area is mostly still in the research and development stage.

4. Industrial Catalysis and Chemical Synthesis—Iron Sources in Homogeneous Catalysis

In fine chemical engineering and organic synthesis, EDTA iron sodium can be used as a homogeneous catalyst or catalyst precursor for specific redox reactions. Chelated iron has good solubility in reaction solutions and its valence state is controllable (Fe³⁺/Fe²⁺ can be switched by photo- or chemical reduction), providing a convenient iron source for some catalytic reactions that require precise control of iron valence state and coordination environment.

Summary

EDTA Iron(III) Sodium Salt (EDTA Iron Sodium/NaFeEDTA) is a sodium salt of a chelate formed by ferric ions and EDTA with an extremely high chelation stability constant (log K ≈ 25). Its chemical formula is C10H12FeN2O8Na·3H2O.

Its entire cross-industry value is anchored in the same chemical principle: in neutral and alkaline environments—pH 8 in agricultural calcareous soils, neutral pH in animal intestines, and weakly alkaline irrigation water—naked Fe²⁺/Fe³⁺ is rapidly oxidized and hydrolyzed into insoluble iron oxides, losing its bioavailability, while the iron ions chelated and protected in EDTA iron sodium remain in a dissolved and available state.

In our daily lives, we are connected with the chelated iron technology of EDTA iron and sodium at different levels through various channels, such as through EDTA iron fertilizer to correct iron deficiency and restore the green color of vegetables and fruit trees, through iron supplementation in feed to maintain health and enter meat, egg and dairy products on the table, through highly absorbable and low-irritant oral iron supplements in pharmacies, and through environmental remediation through treatment of polluted water bodies and soil with EDTA iron and sodium.

In the non-food sector, the value of EDTA iron sodium is distributed across three main areas. Agricultural applications represent the largest and most widespread segment—as a highly efficient chelated iron fertilizer, it plays a crucial role in correcting iron deficiency in crops in calcareous soils (pH 7.5-8.5) globally, fulfilling a task that inexpensive inorganic iron fertilizers like ferrous sulfate cannot accomplish—maintaining iron solubility and root availability in neutral and alkaline pH environments. Foliar spraying and fertigation for high-value iron-sensitive crops such as citrus, grapes, and strawberries are the core application scenarios for EDTA iron sodium in agriculture. In feed applications, it serves as an organic iron source for oral prevention of iron deficiency anemia in newborn piglets and for improving reproductive performance in sows. In pharmaceutical applications, its gastrointestinal friendliness and resistance to dietary interference, combined with chelated iron, provide a mild and highly effective alternative to traditional ferrous sulfate in oral iron supplements. From the new citrus leaves turning from yellow to green on the calcareous soil of the North China Plain to the stable flow of transparent iron solution in the drip irrigation lines of modern greenhouses—all the non-food missions of EDTA iron sodium are responding to the same most basic chemical requirement: iron must not precipitate.