01. EDTA Used as Chelating
02. EDTA DI SODIUM Sequestering Agents
03. EDTA TETRA SODIUM (POWDER/LIQUID) in various Industries
04. EDTA FERRIC AMMONIUM Used in Colour
05. EDTA FERRIC SODIUM Photography
06. DTPA (Powder/Liquid)
07. CHELATED ZINC (EDTA-Zn 12%) Used as Micro
08. CHELATED IRON (EDTA-Fe 12%) Nutrients
09. CHELATED MANGANESE Agriculture
10. CHELATED MANGANESE LIQUID (EDTA-Mn 6.5%)
11. CHELATED COPPER (EDTA-Cu 13%)
12. CHELATED COPPER LIQUID(EDTA-Cu 7.5%)
13. CHELATED MAGNESIUM (EDTA-Mg 6%)
14. CHELATED CALCIUM
EDTA – ETHYLENE DIAMINE TETRA ACETIC ACID
NTA - NITRILO TRI ACETIC ACID
DTPA – DIETHYLENE TRIAMINE PENTA ACETIC ACID
SPECIFICATIONS AND PROPERTIES OF DIFFERENT GRADES OF EDTA/NTA
EDTA A : EDTA Acid
EDTA DS : EDTA Disodium
EDTA TS : EDTA Tetra Sodium
EDTA TL : EDTA Tetra Sodium 40% Solu.
EDTA NaFe : EDTA Ferric Sodium
EDTA NH4Fe : EDTA Ferric Ammonium
Commercial Uses of ETHYLENE DIAMINE TETRA ACETIC ACID & NTA [Chelating Agents]
Boiler Water Treatment: Chelating agents, especially EDTA and NTA, are added to Boiler feed water in order solubilize and tie up trace amounts of incoming water hardness ions which tend to form scale deposits. Other metal ions, such as iron and copper are also scavenged by the chelating agent. This results in a cleaner boiler system with more efficient heat transfer surfaces.
Agriculture: Chelating agents are used to prevent the precipitation of important mineral ions which are essential for maximum crop growth and yields. These trace minerals (iron, zinc, manganese etc.) are able to move through the soil to the plant root system for uptake if they are properly chelated. otherwise, phosphates, carbonates, silicates and organic materials present in the soil will precipitate and “lock-up” these trace elements severely limiting their movement to the plant roots and their ultimate uptake and utilization in producing maximum yields.
Detergent Compounds: Chelating agents are added to detergents to soften the water by tying up water-hardness ions which tend to impede cleaning and rinsing. Both NTA and EDTA are used in this application. EDTA finds particular use in bathtub cleaning products where much of the difficulty lies in removing insoluble calcium soap sucums and films. By removing the calcium from the films, the remaining soap is easily rinsed away. Traces of iron are often present in liquid detergents and the addition of HEEDTA will prevent the precipitation of unsightly deposits in the package.
Industrial Cleaning: The cleaning of scale and other harmful deposits from high-pressure boilers and heat exchange equipment is practiced in a large scale. With the ability to dissolve adherent deposits such as mills scale & other iron rich and calcium rich deposits on the alkaline side, EDTA salts tend to simplify both cleaning procedure and spent solution disposal. Chelating agents are also used in metal cleaning formulations to assist in removing oxide films prior to surface finishing.
Polymerization: The iron chelate of EDTA is used in the catalyst system for the emulsion polymerization of styrene and butadiene to form “GRS” or “cold” rubber. This use depends upon the specialized property of chelating agents to alter the oxidizing and reducing activity of metal ion, in this case, iron. Chelating agents are also used effectively to prevent scale build-up in reactors used in producing polyvinyl chloride emulsions.
Chemical Processing: Chelating agents are often added to various chemicals processes to eliminate metal ion contamination in the finished product or to assist in the removal of traces of remaining catalytic metal ions. Improvement in color often results from the addition of chelating agents to a chemical process. The iron chelates of EDTA and HEDTA are used to effectively and efficiently remove noxious pollutants such as hydrogen sulfide (H2S), sulfur dioxide (SO2) and oxides of nitrogen (NO8) from sour natural gas, refinery off-gases and stack gases from coal or oil burning steam-generating plants. Elemental sulfur (S), sodium sulfate (Na2SO4) and elemental nitrogen (N2) result from this system which is economically regenerated by air.
Photography: EDTA-type chelating agents have been used for many years to prevent precipitation of hard water salts in photographic processing solutions and to stabilize developer solutions toward air oxidation. More recently, the iron chelate of EDTA has rapidly replaced ferricyanide salts as bleaching agents in the development system for color film. The ability to combine the iron-EDTA bleach with the thiosulfate fixer bath to form a convenient bleach-fix or “blix” bath and its ease of regeneration and recycling has brought about a rapid adoption of this system by the photographic industry.
Food and Pharmaceutical: Discoloration and rancid taste and ordor in food products are often caused by the presence of small traces of metal ions such as iron, copper and manganese. The addition of EDTA to products such as mayonnaise, canned and frozen vegetables, shellfish and soft drinks assists in preventing off-taste and color, thereby reducing spoilage losses. EDTA also finds use in the pharmaceutical industry as a treatment to remove lead from the body in cases of lead poisoning and in preserving ophthalmic products from certain harmful bacteria.
Cosmetic: Chelating agents are added to cosmetic products for many of the same reasons that they are added to food and pharmaceutical products. In oil-water emulsions, such as creams and lotions, chelating agents prevent rancid off-odors by tying up trace of catalytic metal ions. Many ingredients are sensitive to trace metal contamination and are protected by the addition of small amounts of EDTA. A number of preservatives used in cosmetics substantially enhanced by the incorporation of EDTA, particularly toward especially troublesome bacteria such as Pseudomonas.
Textiles: Many dyestuffs used by the textile industry are sensitive to small amounts of water hardness and heavy metal ions. This creates splotchy of mottled colors and the formation of unwanted off-shades. These serious problems are corrected by the use of chelating agents. Chelating agents, especially DTPA, are used to stabilize and prevent decomposition of bleaching baths containing hydrogen peroxide. This results in improved whiteness, fewer pinholes in the fabric and an overall savings in peroxide consumption.
Pulp and Paper: In a like manner to textile bleaching with hydrogen peroxide, chelating agents, primarily DTPA are used in the peroxide bleaching of high-grade pulp. The addition of DTPA increases the brightness levels and reduces brightness reversion upon aging while improving the overall efficiency of the bleaching process. Traces of manganese present in the wood pulp are especially detrimental to the peroxide system and significantly reduce the brightness of the finished paper. Chelating agents effectively tie up these traces of manganese.
The Future of Chelating Agents:
The market for amino acid chelating agents, such as EDTA and NTA has grown substantially in the last 10 to 15 years. Much of this growth has been for use in newly developed applications being brought about by rapid changes in technology which are propelled to at least some extent by environmental considerations. chelating agents, while sometimes higher in initial chemical cost, enable certain processes to become closed and recyclable or to be safer to workers and simpler to dispose of properly. This impetus behind changes in chemical process technology is expected to continue. With these changes taking Place, chemists and chemical engineers will continue to explore and exploit the interesting and diverse functions of these unusual industrial chemicals.
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