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Nitrilotriacetic acid (NTA)

Nitrilotriacetic acid (NTA)

Nitrilotriacetic acid (NTA) is the aminopolycarboxylic acid with the formula N(CH2CO2H)3. It is a colourless solid that is used as a chelating agent, which forms coordination compounds with metal ions (chelates) such as Ca2+, Co2+ , Cu2+, and Fe3+.


CAS NO: 139-13-9 ,49784-42-1
EC NO: 205-355-7
IUPAC NAMES:
2,2',2''-nitrilotriacetic acid
2-[bis(carboxymethyl)amino]acetic acid
Glycine, N,N-bis(carboxymethyl)-
N,N-Bis(carboxymethyl)glycine, NTA, Tris(carboxymethyl)amine
Nitrilotriacetic Acid
Nitrilotriacetic acid
nitrilotriacetic acid
Nitrilotriacetic acid
nitrilotriacetic acid
Nitrilotriacetic Name
Nitrilotriessigsäure
NTA acid

SYNONYMS:
NITRILOTRIACETIC ACID;139-13-9;2,2',2''-nitrilotriacetic acid;Triglycollamic acid;Nitrilotriacetate;Aminotriacetic acid;Complexon I;Trilon A;NTA;Glycine, N,N-bis(carboxymethyl)-;N,N-Bis(carboxymethyl)glycine;2-[bis(carboxymethyl)amino]acetic acid;Komplexon I;Titriplex ;Versene NTA acid;Nitrilotriessigsaeure;Hampshire NTA acid;Tri(carboxymethyl)amine;Tris(carboxymethyl)amine;Acetic acid, nitrilotri-;Nitrilo2,2',2''triaceticacid;MFCD00004287;CHEL300;NCIC02766;Nitrilotriaceticacid(NTA);UNIIKA90006V9D;alpha,alpha',alpha''Trimethylaminetricarboxylicacid;2(bis(carboxymethyl)amino)aceticacid;CHEBI:44557;KA90006V9D;Nitriloacetate;DSSTox_CID_939;DSSTox_RID_75878;Nitrilotriaceticacid,99%;DSSTox_GSID_20939;Nitrilotriaceticacid;CAS-139-13-9;CCRIS 436;Aminotriethanoic acid;N,N-Bis(carboxymethyl)glysine;HSDB 2853;Kyselina nitrilotrioctova [Czech];Kyselina nitrilotrioctova;NSC 2121;EINECS 205-355-7;BRN 1710776;AI3-52483;H3nta;Potassium cadmium nitrilotriacetate;EINECS 256-488-2;nitrilotriacetic-acid;WLN: QV1N1VQ1VQ;EC 205-3557;Cambridgeid5122183;NitrilotriessigsAcurrencyure;ACMC1BQ36;N(CH2COOH)3;NTA(Nitrilotriaceticacid);SCHEMBL20409;4-040002441(BeilsteinHandbookReference);MLS000069464;BIDD:ER0361;Glycine,Nbis(carboxymethyl)-;Nitrilo2,2''triaceticacid;CHEMBL1234848;DTXSID6020939;NSC2121;HMS2232K17;CCG213;NSC2121;STR02791;ZINC1849692;Nitrilotriaceticdp.a.,99%;Tox21_202195;Tox21_300156;ANW20498;BBL002469;SBB006593;STK387109;AKOS005441655;DB03040;MCULE5696288379;NCGC00091141-01;NCGC00091141-02;NCGC00091141-03;NCGC00091141-04;NCGC00254116-01;NCGC00259744-01;BP-30104;Cadmate(1-),(N,N-bis((carboxykappaO)methyl)glycinato(3-)kappaN,kappaO)-,potassium(1:1(T4)-;Cadmate(1(N,Nbis((carboxykappaO)methyl)glycinato(3-)kappaN,kappaO)-,potassium(T4)-;I536;SMR000054748;2[bis(carboxymethyl)amino]essigsäure;DB042463;FT0631809;N0098;NITRILOTRIACETICACIDACSGRADE100G;Nitrilotriaceticacid,SigmaGrade,>=99%;ST50306920;T7392;C14695;Nitrilotriaceticacid,ACSreagent,>=99.0%;84771-EP2270017A1;84771-EP2301941A1;84771-EP2305808A1;90564-EP2272834A1;90564-EP2301929A1;90564-EP2301935A1;90564EP2305674A1;90564EP2372017A1;90564EP2374780A1;90564EP2374781A1;Nitrilotriaceticacid,BioUltra>=99.0(T);.alpha.,.alpha.''Trimethylaminetricarboxylicacid;Q425340;J007239;F19056980;Z1889996324;Nitrilotriaceticacid,ACSreagent,forcomplexometry,>=98%;Nitrilotriaceticacid,UnitedStatesPharmacopeia(USP)ReferenceStandard;Potassium(N,Nbis(carboxymethyl)glycinato(3N,O,O',O'')cadmate(1-);Nitrilotriacetic acid, Pharmaceutical SecondaryStandard;CertifiedReferenceMaterial;alpha,alpha',alpha''-trimethylaminetricarboxylicacid;aminotriaceticacid;chel300;hampshirentaacid;nitrilo2,2',2''triaceticacid;N,Nbis(carboxymethyl)glycine;NTA;ComplexonI;titriplexi;tri(carboxymethyl)amine;triglycine;triglycollamicacid;TriloneA;versenentaacid;ai352483;chel300;complexoni;Glycine,N,Nbis(carboxyme;hampshirentaacid;komplexoni;kyselinanitrilotrioctova;kyselinanitrilotrioctova(czech);Trimethylamine-α,α',α"-tricarboxylic acid;Nitrilo triacetic acid

Nitrilotriacetic acid (NTA)

Production and use
Nitrilotriacetic acid is commercially available as the free acid and as the sodium salt. It is produced from ammonia, formaldehyde, and sodium cyanide or hydrogen cyanide. Worldwide capacity is estimated at 100 thousand tonnes per year.[6] NTA is also cogenerated as an impurity in the synthesis of EDTA, arising from reactions of the ammonia coproduct.[7]

Coordination chemistry and applications
NTA is a tripodal tetradentate trianionic ligand.[8]

The uses of NTA are similar to those of EDTA, both being chelating agents. It is used for water softening and as a replacement to sodium and potassium triphosphate in detergents, and cleansers.

In one application, NTA as a chelating agent removes Cr, Cu, and As from wood that had been treated with chromated copper arsenate.[9]

Laboratory uses
In the laboratory, this compound is used in complexometric titrations. A variant of NTA is used for protein isolation and purification in the His-tag method.[10] The modified NTA is used to immobilize nickel on a solid support. This allows purification of proteins containing a tag consisting of six histidine residues at either terminus.[11]

The his-tag binds the metal of metal chelator complexes. Previously, iminodiacetic acid was used for that purpose. Now, nitrilotriacetic acid is more commonly used.[12]

For laboratory uses Ernst Hochuli et al. 1987 coupled the NTA ligand and Nickel-ions to agarose beads.[13] This Ni-NTA Agarose is the most used tool to purify his tagged proteins via affinity chromatography.

Pharmacology    
Nitrilotriacetic Acid is a white, crystalline solid compound. Nitrilotriacetic acid is mainly used as a chelating and eluting agent and is found in laundry detergents.

Mechanism of Action    
A positive synergistic action was produced by nitrilotriacetic acid in combination with soluble chromium(VI) as potassium dichromate in the induction of gene mutations in Salmonella typhimurium and Drosophila melanogaster. The possibility that this action depended on an effect of nitrilotriacetic acid on chromium(VI) reduction by cellular proteins was demonstrated. Gene mutations were detected by the Ames plate incorporation test on strains (TA-100), (TA-92), (TA-104) and (TA-103) of Salmonella typhimurium. In both the Salmonella and Drosophila systems, the nitrilotriacetic acid synergistically increased the mutagenicity of subtoxic doses of chromium(VI) while at higher chromium(VI) dose levels a decline of mutation frequency was noted in the presence of nitrilotriacetic acid, probably as a result of toxicity. Both effects may be referred to enhanced availability of the final genotoxic agent in the presence of nitrilotriacetic acid. The interaction was particularly evident in strains (TA-100) and (TA-104) which carried mutations affecting cell wall permeability and DNA repair. In these strains, the uptake of chromium(VI) and nitrilotriacetic acid was increased and the resulting DNA damage repaired less efficiently or by error prone mechanisms. Nitrilotriacetic acid may facilitate chromate uptake by the anion carriers of the cell membrane. Other mechanisms linked to its chelating action may also be important as suggested by the significant synergistic effect on chromium(VI) mutagenicity produced by ethylenedinitrilotetraacetic acid at very low doses, which do not modify chromium(VI) reduction by Salmonella proteins in cell free conditions.

Industry Uses    
Paint additives and coating additives not described by other categorie


Consumer Uses    
Paints and coatings

Methods of Manufacturing
Alkaline Process: ... In a typical process, aqueous NaCN solution is fed into a cascade reactor system along with formaldehyde solution. Ammonia is liberated during the synthesis and need not be supplied. The reaction takes place at 80 - 100 °C. Because of the high pH (ca. 14), triscyanomethylamine N(CH2CN)3 is hydrolyzed in situ to Na3NTA. This process generates three times as much ammonia as it consumes and the ammonia concentration must be limited to suppress the production of substances with low degrees of carboxymethylation (glycine, iminodiacetic acid). This is largely achieved by continuously distilling off the ammonia with steam or air throughout the process. However, formation of byproducts (chiefly glycolic acid, hexamethylenetetramine, and the above-mentioned amino acids) cannot be completely prevented. The resulting solution is sold directly as a 40-wt% solution, or used in the production of Na3NTA.H2O in powder form, or acidified to pH 1-2 to yield the acid.

Major uses
The trisodium salt of nitrilotriacetic acid (NTA) is used in laundry detergents as a "builder" toreplace phosphates because of its ability to chelate calcium and magnesium ions (1). NTA isused extensively in the treatment of boiler water to prevent the accumulation of mineral scaleand, to a lesser extent, in photography, textile manufacture, paper and cellulose production,and metal plating and cleaning operations. Its use as a therapeutic chelating agent for thetreatment of manganese poisoning (2) and iron overloading has been suggested (3).

Environmental fate
NTA is degraded principally by microorganisms by carbon–nitrogen cleavage with theformation of such intermediates as iminodiacetate, glyoxylate, glycerate, glycine, andammonia (4–6); the metabolic end-products are carbon dioxide, water, ammonia,and nitrate(7). NTA mobilizes heavy metals from aquatic sediments (8) and is present in water primarilyin the form of metal complexes (9), most of which degrade rapidly. Under certain conditions,it is broken down by photochemical and chemical reactions (7).The half-life for biodegradation of NTA in groundwater at 1–100 µg/litre is approximately 31h (10). Concentrations of 5–50 mg/litre completely disappeared from river water containingacclimatized microorganisms in 2–6 days; concentrations below 5 mg/litre are expected todegrade within 1 day (11,12). Acclimatization of microorganisms in two lake waters resultedin the reduction of the disappearance time of up to 10 mg of NTA per litre from 6 and 11 daysto 4 and 3 days, respectively (13). Sand-associated bacteria adapt more quickly to NTA anddegrade it more actively than do plankton and algae (14).
ANALYTICAL METHODS
NTA concentrations in water may be determined by gas chromatography with a nitrogenspecific detector. This method is suitable for the detection of levels as low as 0.2 µg/litre.


Odorless white solid. Sinks in and mixes with water.


NITRILOTRIACETIC ACID(139-13-9) is incompatible with strong oxidizers, aluminum, copper, copper alloy and nickel. NITRILOTRIACETIC ACID(139-13-9) is also incompatible with strong bases.

Water Insoluble.

Toxicity and health hazard of these compounds are low. Contact with eyes causes irritation.

Nitrilotriacetic acid (NTA) was used as a phosphate replacement in laundry detergents in the late 1960s. In 1971, the use of NTA was discontinued. The possibility of resumed use arose in 1980. NTA is now used in laundry detergents in states where phosphates are banned. NTA is also used as a boiler feed-water additive at a maximum use level of 5 ppm of trisodium salt. Currently, the remaining nondetergent uses of NTA are for water treatment, textile treatment; metal plating and cleaning; and pulp and paper processing.

Flash point data for this chemical are not available; however, NITRILOTRIACETIC ACID is probably combustible.

Move victim to fresh air.  Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Medical observation is recommended for 24 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy.

Description
Nitrilotriacetic Acid, Reagent, ACS, also known as Triglycine, is used as a chelating agent. As an ACS grade quality reagent, its chemical specifications are the de facto standards for chemicals used in many high-purity applications and typically designate the highest quality chemical available for laboratory use. Spectrum Chemical manufactured Reagent ACS grade products meet the toughest regulatory standards for quality and purity.

Nitrilotriacetic Acid, CP is an aminopolycarboxylic acid used as a chelating agent and for water softening; it can also be used as a replacement to sodium and potassium triphosphate in cleansers and detergents. CP or Chemically Pure grade products supplied by Spectrum are indicative of a grade suitable for general industrial use.

Physical State: Solid
Appearance: white
Odor: none reported
pH: 2.3 (saturated)
Vapor Pressure: Negligible.
Vapor Density: Not available.
Evaporation Rate:Negligible
Viscosity: Not available.
Boiling Point: Not available.
Freezing/Melting Point:241 deg C
Decomposition Temperature:Not available.
Solubility: Very slightly solutble in water
Specific Gravity/Density:>1.000
Molecular Formula:N(CH2COOH)3
Molecular Weight:191.0661

Nitrilotriacetic acid is a chelating agent which forms coordination compounds with metal ions. Nitrilotriacetic acid is used in complexometric titrations and as well as for protein isolation and purification in the His-tag method. 

Nitrilotriacetic acid (NTA), when added to solid or liquid media, stimulated the growth of Pseudomonas strains, whereas other synthetic iron-chelators, such as ethylenediaminediacetic acid, ethylenediaminetetraacetic acid, ethylenediaminedihydroxyphenyl acetic acid or ethylene glycol-bis-(β-aminoethyl ether)-tetraacetic acid, resulted in concentration-dependent growth inhibition. Experimental data such as stimulation of growth in iron-poor media, inhibitory effect on siderophore biosynthesis, promotion of iron-uptake by NTA Nitrilotriacetic acid , together with the inability of the Pseudomonas strains to use NTA Nitrilotriacetic acid  as a carbon and/or a nitrogen source, demonstrated that NTA Nitrilotriacetic acid  favours the bacterial growth of Pseudomonas through its scavenging properties for iron.

NTA Nitrilotriacetic acid is a trisodium salt of nitrilotriacetic acid and has been used as a chelating (binding) agent for more than 50 years. Nitrilotriacetate is used worldwide in a variety of market areas, with major emphasis in the detergent industry. NTA Nitrilotriacetic acid effectively controls a variety of metal ions in wash water thus allowing cleaning ingredients to work better. NTA Nitrilotriacetic acid also works well in the following applications:

• Laundry detergents
• Automatic dishwashing products
• Scale control in boiler water treatment
• Bottlewash formulations for removal of trace contaminating metal salts
• Carpet cleaning products
• Hard surface cleaners
• Metal cleaning and treatment
• Petroleum production and refining processes
• Thermochemical pulp processes
• Removal of hydrogen sulfide from natural gas (gas scrubbing)
• Polymer processing
• Textile scouring, bleaching and dyeing processes
• Vehicle washing products
• Natural gas fracking formulations (corrosion control)

Environmental Effects Overview
Through many studies conducted around the world, NTA Nitrilotriacetic acid has been shown to have no negative effects on the environment when manufactured, formulated and used in a responsible manner. The studies have determined:
• Nitrilotriacetic acid NTA is not persistent in the environment, and poses no risks to the environment from consumer and industrial use
• Nitrilotriacetic acid NTA is readily broken down in both aerobic and septic waste disposal systems
• Nitrilotriacetic acid NTA is readily biodegradable in freshwater and saltwater aquatic environments
•Nitrilotriacetic acid NTA is readily biodegradable in anaerobic conditions
• Nitrilotriacetic acid NTA undergoes photo and chemical degradation.
• Nitrilotriacetic acid NTA ultimately breaks down into carbon dioxide, water and inorganic nitrogen
• While the above facts are true for Nitrilotriacetic acid NTA as sold, they are also true for metal complexes of Nitrilotriacetic acid NTA
• Due to its rapid biodegradation Nitrilotriacetic acid NTA has been shown to have little effect on the mobilization of heavy metals in the sewage treatment or aquatic environments
• While studies show that Nitrilotriacetic acid NTA is toxic to algae, these effects are related to mineral starvation. These effects would never be seen in the natural environment due to gross excess of metals in the aquatic environment.

Physical Properties Overview
Nitrilotriacetic acid NTA is available as a free flowing powder or 40% water solution. These products obviously have different properties and handling characteristics. Both products are classified as not regulated for transport, and can be shipped by any method. Nitrilotriacetic acid NTA’s properties have been well characterized:
• Nitrilotriacetic acid NTA powder is a monohydrate under most circumstances
• Nitrilotriacetic acid NTA powder is not flammable or combustible.  Nitrilotriacetic acid NTA powder is not a dust
explosion risk.
• Nitrilotriacetic acid NTA, if heated to decomposition, breaks down into carbon, carbon dioxide, nitrogen oxides, and water.
• Nitrilotriacetic acid NTA powder contains a distribution of particle sizes
• Nitrilotriacetic acid NTA powder is highly water soluble (457 grams Nitrilotriacetic acid NTA per liter of solution at 20°C)
• Nitrilotriacetic acid NTA powder, if spilled, can be slippery if it becomes damp.
• Nitrilotriacetic acid NTA solution is a low viscosity fluid
• Nitrilotriacetic acid NTA solution is non-flammable and not corrosive to metals in normal use and storage conditions.

The chelating characteristics of nitrilotriacetic acid (NTA) are presented and illustrated with respect to its application in medicine, pharmacy, industry (including detergent formulations), agriculture, and the food industry. The analytical chemistry of NTA is presented with respect to its application as an analytical reagent as well as in the separation and determination of NTA itself. A brief account on the toxicology and bio‐environmental aspects of this chelating agent is also part of this review. Special attention is paid to the controversy generated around NTA and its trisodium salt as a possible substituent for phosphate in heavy‐duty detergent formulations.


Nitrilotriacetic acid and its sodium salts have been produced since the 1930s for use as metal chelating agents in household and industrial detergents, industrial water treatment, textile preparation and metal finishing. Occupational exposure to nitrilotriacetic acid and its salts may occur during its production and use, but data on levels are limited. Exposure to nitrilotriacetic acid, and presumably to its water-soluble metal complexes, occurs as a result of its presence in household detergents and in drinking-water.

Uses
*Nitrilotriacetic acid is a chelating agent which forms coordination compounds with metal ions. Nitrilotriacetic acid is used in complexometric titrations and as well as for protein isolation and purif ication in the His-tag method.
*Used in sequestration of metals; chelometric analysis

NTA Nitrilotriacetic acid has numerous commercial applications as a metal ion chelator, including pricipally its use in cleaning products, industril water treatment, textile preparation and metal finishing. It has also been used to a lesser extent in the pulp and paper industiy, in rubber processing, in photographic products, in the electrochemical industiy, in the tanning of leather, and in cosmeties (Anderson et al., 1985; Universities Assoiated for Research and Education in Pathology, 1985). The major use of NTA Nitrilotriacetic acid , as the triium salt, has been in detergent systems as a chelating agent and as a laundiy detergent builder. NTA Nitrilotriacetic acid was originally proposed as a substitute for phosphates in detergents, when the eutrophic effect of phosphates on the aquatic envionment was recognized. It has been accepted for use as an ingredient in domestic detergent products in at least 16 countries and has actually been used in detergents in Canada and several European countries since the early 1970s. NTA Nitrilotriacetic acid  is also used to reduce fabric yellowig by hyphlorite bleach and to increase the effectiveness in hard water of liquid detergent-sanitizer formulations based on quaternaiy ammonium germicides (Universities Associated for Research and Education in Pathology, 1985; W.R. Grace & Co., 1985; Wendt et aL., 1988). NTA Nitrilotriacetic acid  can chelate metal ions that commonly cause water 'hardness' (Ca2 + and Mg2 +) and is widely used to control precipitation and scling of salts of these ions, for example, in boiler feedwater. Various salts of NTA Nitrilotriacetic acid  have been used to remove scle. Since the sodium-calcium NTA  Nitrilotriacetic acid complex is relatively insoluble, it can form a coating on the scle andretard further scle formation. lron oxide deposits such as mil scle are removed with NTA Nitrilotriacetic acid,ammonium salts in the alkaline pH range, resulting in a degreased and cleaned surface (Anderson et al., 1985; WR. Grace & Co., 1985).Trace metals in dye processing are often respnsible for uneven dyeing of stock, piece and continuous goos by forming interferig metal lakes, whieh result in streakig and dulling of shades. Hardness can be controlled and heavy metals eliminated by incorprating NTA Nitrilotriacetic acid in the processing. NTA Nitrilotriacetic acid  is also used in scurig and fulling operations, in peroxide bleaching and in desizing operations (Anderson et al., 1985; W.R. Grace & Co., 1985).The addition of NTA Nitrilotriacetic acid to conventional alkaline metal cleaners assists in dissolvig water-insoluble metal oxides and hydroxides which are formed when metals corrode .

Nitrilotriacetic Acid (NTA) is a chemical used in laundry detergent, as a scale prevention method for boilers, in photography, leather tanning, in textile and paper manufacturing, and as a medical treatment for manganese poisoning. Its use in detergents was banned in the 1970s, but resumed in the 1980s to replace phosphates that were then being banned.

Nitrilotriacetic acid is organic chelating agent used to control the concentration of metal ions in aqueous systems.

Nitrilotriacetic Acid is a white, crystalline solid compound. Nitrilotriacetic acid is mainly used as a chelating and eluting agent and is found in laundry detergents.

Nitrilotriacetic acid is a tricarboxylic acid and a NTA.
Nitrilotriacetic acid (NTA) is the aminopolycarboxylic acid with the formula N(CH2CO2H)3.
Nitrilotriacetic acid is a colourless solid that is used as a chelating agent, which forms coordination compounds with metal ions (chelates) such as Ca2+, Co2+ , Cu2+, and Fe3+.

Nitrilotriacetic acid is a chelating agent which forms coordination compounds with metal ions. Nitrilotriacetic acid is used in complexometric titrations and as well as for protein isolation and purif ication in the His-tag method.

In aqueous solutions, Nitrilotriacetic acid competes for metal ions with other anions, such as hydroxide, sulphate, sulphide, carbonate and oxalate, that form sparingly soluble metal salts.
The formation of chelates reduces the concentration of free metal ions [Men+] to such an extent that the solubility products of many sparingly soluble metal salts are no longer exceeded.
The result is that the salts no longer precipitate or may even redissolve.

Conditional stability constants [log Kcond] take into account the stability constant K as well as the acid base dissociation equilibria.

The following curves show the conditional stability constants for selected NTA chelates.

Chemical stability: Nitrilotriacetic acid is chemically very stable.

Nitrilotriacetic acid exhibits a higher stability than other organic chelating agents such as citric acid, tartaric acid and gluconates – especially at elevated temperatures.
Whereas inorganic sequestring agents (e.g. phosphates) may hydrolyse at high temperatures, Nitrilotriacetic acid is stable – even when heated to 200 °C under pressure.

Nitrilotriacetic acid melts at approx. 245 °C.

Nitrilotriacetic acid is resistant to strong acids and bases.
It is gradually broken down by chromic acid, potassium permanganate and other strong oxidizing agents.
Stability in the presence of hydrogen peroxide, percarbonate and perborate is sufficient for joint application.
Nevertheless, we do not recommend combining Nitrilotriacetic acid and peroxides in liquid formulations.

Sodium hypochlorite and other substances that release chlorine cause Nitrilotriacetic acid to decompose.
Alkaline earth and heavy metal complexes are broken down.

Corrosion: Nitrilotriacetic acid stabilizes polyvalent metal ions, which means that it can increase the rate at which metals dissolve.
Nevertheless, with the exception of aluminium, an oxidizing agent such as air always has to be present for corrosion to take place.
Unalloyed steel is prone to corrosion in media that contain air, but corrosion can be reduced substantially if the pH is in the alkaline range and can be eliminated almost completely if oxygen and other oxidizing agents are excluded.
Steel that is cleaned with Nitrilotriacetic acid in the slightly alkaline range, which is the optimum pH range for the Nitrilotriacetic acid, is much less prone to corrosion than if it is cleaned with acids.

The only type of corrosion that has been with Nitrilotriacetic acid is uniform corrosion: pitting or stress cracking have not been observed in media with a low chloride content.
One of the advantages of Nitrilotriacetic acid is that it can be supplied with very low chloride contents.

The following information on materials is of a very general nature, because corrosion depends on many different factors such as exposure to air, galvanic corrosion caused by the presence of different materials and by the flow patterns of liquids.
The compatibility of Nitrilotriacetic acid with different materials needs to be tested in each individual case.
The uses of NTA are similar to those of EDTA, both being chelating agents.
It is used for water softening and as a replacement to sodium and potassium triphosphate in detergents, and cleansers.

In one application, NTA as a chelating agent removes Cr, Cu, and As from wood that had been treated with chromated copper arsenate.

Laboratory uses
In the laboratory, this compound is used in complexometric titrations. A variant of NTA is used for protein isolation and purification in the His-tag method.
The modified NTA is used to immobilize nickel on a solid support. This allows purification of proteins containing a tag consisting of six histidine residues at either terminus.

The his-tag binds the metal of metal chelator complexes.
Previously, iminodiacetic acid was used for that purpose. Now, nitrilotriacetic acid is more commonly used.

For laboratory uses Ernst Hochuli et al. 1987 coupled the NTA ligand and Nickel-ions to agarose beads.
This Ni-NTA Agarose is the most used tool to purify his tagged proteins via affinity chromatography.

Metal cations found in boiler water, such as calcium, magnesium, iron, and copper, can be solubilized to prevent deposition and scale formation.
The functional agents in this type of treatment are known as chelants. Chelants are organic, anionic chemicals that form soluble compounds with the metals.
The two chief chelating chemicals used in industrial boiler water treatment are ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA).

Chelants are added continuously in the stoichiometric quantity required to solubilize any metal contaminants present in the boiler water.
The stabilities of the resultant metal–chelate reaction compounds vary considerably.
EDTA has more coordination sites than NTA and forms stronger soluble complexes with the metal cations.
However, EDTA in excess of that required for contaminant chelation can decompose in the boiler water and large excesses of EDTA and NTA can react with the magnetite (Fe3O4) film protecting the boiler.
Other anions present in the boiler water (e.g., phosphate, silicate, and hydroxide) tend to compete with chelants, limiting their effectiveness.

For these reasons, chelant treatment chemistry must be precise.
Frequent analytical testing of the feedwater and internal boiler water is necessary to maintain a proper chelant feed rate.

Polymeric dispersants are used to supplement chelant treatment.
Polymers are particularly effective in dispersing metal oxides and sludges that form due to chelant instabilities.
Proper application of a chelant–dispersant treatment results in clean heat transfer surfaces and efficient boiler operations.

Chelant Treatments
Realizing the shortcomings of residual phosphate chemistry in the way it handles feedwater hardness contamination (precipitation), alternative treatment chemistries were developed.

The first was the use of chelants to solubalize the hardness contaminants. The most common chelants used were ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA).
Both EDTA and NTA form soluble complexes with calcium and magnesium that are stable to relatively high temperatures, up to 6.8 MPa g (1000 psi g).
The removal of hardness contaminants from the boiler, now in a soluble form, are no longer limited by the continuous blowdown’s limited ability to remove suspended solids from the circulating boiler water.
If the species in question is soluble in the feedwater, remains soluble in the boiler water and is nonvolatile, the continuous blowdown removes that species at 100% efficiency.

Theoretically, if the required stoichiometric ratio of chelant to hardness were maintained, there would be no accumulation of hardness-based deposits in the boiler.
However in practice, there are variations in the level of hardness contaminants in the feedwater, and some overfeed must be applied continually to account for these variations.
This overfeed is typically controlled to result in a small residual chelant concentration in the boiler water above that required for the actual hardness.
It was found that this boiler water chelant residual must be controlled very tightly because high levels of the residual can result in corrosion of the boiler base material.
This corrosion is most likely to occur in areas of high fluid velocity or turbulence in the boiler.


INTRODUCTION 
The soluble salts of ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) have wide industrial and agricultural applications. NTA is becoming increasingly well known because of its potential use as a partial substitute for polyphosphates in the detergent industry. Because of the comparatively low cost of manufacture and the high chelating power, increasing quantities of NTA have been used for detergent formulations since 1966. EDTA and NTA are now widely employed in agriculture as carriers for micronutrients (Zn, Mn, Fe, Cu, Mo). NTA chelated micronutrients have been mostly granular formulations for zinc and iron; EDTA chelated micronutrients, which have been in use for a longer period of time than NTA, include powdered, granular, and liquid formulations for iron,- zinc,- copper, and manganese. EDTA is used as a food preservative. Both chelates find extensive use for removal of hardwater scales from industrial plants. NTA has been used for 2,4-D herbicide concentrates which are completely soluble in water. In aqueous solutions, chelating agents such as EDTA and NTA form strong, soluble complexes with polyvalent cations and thereby eliminate the detrimental effects often caused in aqueous systems by metallic impurities. The dyeing, textile 2 processing, tanning, and photographic industries use those chelates for the removal of metal-ion contaminations in their sources of water. But the addition of such compounds to soils or natural waters by detergent products released from sewage treatments could cause adverse effects by binding cations associated with soil or sediment phosphate and releasing the phosphate to the aqueous phase of the soil-water or sedimentwater systems. This release of phosphate may lead to eutrophication of water resources by phosphate derived from soils and sediments. Since NTA complexes iron, aluminum, calcium, magnesium, and other metals, information concerning its effects on the release of phosphate associated with these metal ions in soils or river, and lake sediments, is of vital importance in relation to possible use of this compound as a substitute for phosphates in detergents. On the other hand, the ability of EDTA and NTA to bind Fe, Al, Ca, Mg, and other metal ions makes them potentially useful extractants for the study of phosphates in soils and, possibly, in soil testing for fertilizer recommendations. Also, these compounds could serve as a single extractant for the determination of not only phosphates but also other ions of interest in soils, particularly the micronutrient elements. A few attempts have been made to use EDTA to bind the various metal ions in soils and thereby release the phosphate 3 associated with these metal ions. But difficulties have been encountered in the determination of the released phosphate because EDTA interferes with phosphomolybdenum color developed in the colorimetric methods employed for determination of phosphate. Probably because of this difficulty, very few investigations have been conducted to determine the potential use of these chelates in the characterization of soil phosphates, although EDTA has been widely employed for the extraction of some micronutrients from soils. To my knowledge NTA has not been used in studies related to phosphates in soils. The objectives of this investigation were:
 (a) to develop a satisfactory colorimetric method for the determination of phosphates in aqueous solutions and soil extracts of EDTA and NTA; 
(b) to study the factors that affect the release of soil phosphates by EDTA and NTA solutions; 
(c) to investigate any possible relationships between EDTA- and NTA-extractable phosphates and calcium, magnesium, iron, and aluminum ions in the surface and subsoils of the major soil types in Iowa. 

Nitrilotriacetic acid, commonly known as NTA (N(CH{sub 2}CO{sub 2}H){sub 3}), can be considered a representative of the polyamino-carboxylic family. The results presented in this paper describe the thermodynamical complexation and structural investigation of An(IV) complexes with NTA in aqueous solution. In the first part, the stability constants of the An(IV) complexes (An = Pu, Np, U, and Th) have been determined by spectrophotometry. In the second part, the coordination spheres of the actinide cation in these complexes have been described using extended X-ray absorption fine structure spectroscopy and compared to the solid-state structure of (Hpy){sub 2}[U(NTA){sub 2}].H{sub 2}O. These data are further compared to quantum chemical calculations, and their evolution across the actinide series is discussed. In particular, an interpretation of the role of the nitrogen atom in the coordination mode is proposed. These results are considered to be model behavior of polyamino-carboxylic ligands such as diethylenetriamine pentaacetic acid, which is nowadays the best candidate for a chelating agent in the framework of actinide decorporation for the human body.

Nitrilotriacetic acid trisodium salt can be utilized as a chelating agent in lightening and as a sequestrant home builder. It is similarly made use of in sun tanning, artificial rubber, textiles, medicines, minimized phosphate, as well as phosphate-free cleaning agents. As well as also in boiler-water treatment. Additionally, people also make use of trisodium NTA for refining, as well as likewise the processing of steels. It is also used in the paper-pulp-board field. This nitrilotriacetic acid trisodium can be used as an additive to building and construction products.

Consumer Uses
This substance is used in the following products: washing & cleaning products, coating products, biocides (e.g. disinfectants, pest control products), fillers, putties, plasters, modelling clay, adhesives and sealants and polishes and waxes.
Other release to the environment of this substance is likely to occur from: outdoor use, indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters), outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids), outdoor use in long-life materials with low release rate (e.g. metal, wooden and plastic construction and building materials), outdoor use in long-life materials with high release rate (e.g. tyres, treated wooden products, treated textile and fabric, brake pads in trucks or cars, sanding of buildings (bridges, facades) or vehicles (ships)), indoor use in long-life materials with low release rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and cardboard products, electronic equipment) and indoor use in long-life materials with high release rate (e.g. release from fabrics, textiles during washing, removal of indoor paints).

Article service life
Other release to the environment of this substance is likely to occur from: outdoor use in long-life materials with low release rate (e.g. metal, wooden and plastic construction and building materials), outdoor use in long-life materials with high release rate (e.g. tyres, treated wooden products, treated textile and fabric, brake pads in trucks or cars, sanding of buildings (bridges, facades) or vehicles (ships)), indoor use in long-life materials with low release rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and cardboard products, electronic equipment) and indoor use in long-life materials with high release rate (e.g. release from fabrics, textiles during washing, removal of indoor paints).

Widespread uses by professional workers
This substance is used in the following products: pH regulators and water treatment products and laboratory chemicals.
This substance is used in the following areas: health services and scientific research and development.
Release to the environment of this substance can occur from industrial use: in processing aids at industrial sites, in the production of articles, as processing aid and of substances in closed systems with minimal release.
Other release to the environment of this substance is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), outdoor use, indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters) and outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids).

Uses at industrial sites
This substance is used in the following products: pH regulators and water treatment products and laboratory chemicals.
This substance is used in the following areas: formulation of mixtures and/or re-packaging, health services and scientific research and development.
This substance is used for the manufacture of: chemicals.
Release to the environment of this substance can occur from industrial use: in processing aids at industrial sites, in the production of articles, as processing aid and of substances in closed systems with minimal release.
Other release to the environment of this substance is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), outdoor use, indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters) and outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids).

NTA is used as a chelating and sequestering agent, and as a builder in synthetic detergents.It is also used as an eluting agent in the purification of rare earth elements, as a boiler feed water additive, in water and textile treatment, in metal plating and cleaning and in pulp and paper processing.

Nitrilotriacetic acid (NTA) is an aminotricarboxylic acid with an empirical formula of C6H9NO6 . In the undissociated acid form, it is composed of needles or prismatic crystals. NTA has a melting point of 241.5°C; its solubility in water at 22.5°C is 1.28 mg/mL. The pH of the saturated solution is 2.3. 
NTA can sequester metal ions to form water-soluble complexes; it is an important chelating agent, with many industrial applications. Because of its ability to chelate calcium and magnesium ions, the trisodium salt is used in laundry detergents as a “builder” to replace phosphates, the use of which has been restricted by legislation in some countries owing to their contribution to the eutrophication of lakes and ponds. In 1977, the amount of NTA used in detergents in Canada was 27 299 tonnes; more recent data on consumption were not identified.1 NTA is also used extensively in the treatment of boiler water to prevent accumulation of mineral scale. It is used to a lesser extent in photography, textile manufacturing, paper and cellulose production, metal plating and cleaning operations. NTA has been proposed as a therapeutic chelating agent for manganese poisoning2 and for the treatment of iron overloading, as it has a synergistic effect on the mobilization of iron by desferrioxamine.
NTA is present in the environment primarily as a result of its release in sewage. It biodegrades readily and, under certain conditions, is broken down by photochemical and chemical reactions.4 NTA is degraded principally by microorganisms, by carbon– nitrogen cleavage with the formation of intermediates such as iminodiacetate, glyoxylate, glycerate, glycine and ammonia; 5–7 the metabolic end products are carbon dioxide, water, ammonia and nitrate.4 The rate of biodegradation is largely influenced by acclimatization.
of the microorganisms,8,9 temperature,10,11 dissolved oxygen concentration in water,12 NTA concentration13 and water hardness.14 Most NTA–metal complexes degrade rapidly.

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