EDTA 2Na
EDTA 2Na
synonyms:
EDTA disodium salt; 139-33-3; Disodium EDTA; Ethylenediaminetetraacetic acid disodium salt; Edta disodium; Disodium ethylenediaminetetraacetate; AK164289; EDTA 2Na; Disodium ethylenediaminetetraacetic acid;Etilendiamin tetraasetik asit; etilendiamintetrasetikasit; etilen diamine asetik asit; EDTA; tetraasetik asit; tetraasetikasit; etilendiamin;edetat;1,2-Bis (N,N-dicarboxymethylamino)-ethane;3,6-Diazaoctanedioic acid, 3,6-bis(carboxymethyl)-;62: PN: US20050026181 PAGE: 33 claimed protein;Acetic acid, (ethylenedinitrilo)tetra-;Acetic acid, 2,2′,2”,2”’-(1,2-ethanediyldinitrilo)tetrakis-;Acide edetique;acido edetico;Acroma DH 700;AETHYLENDIAMIN-TETRAESSIGSAEURE;Celon A;Celon ATH;Cheelox;Chelest 3A;Chemcolox 340;Clewat TAA;Clewat TTA;Complexon II;Dissolvine E;Dissolvine Z;DOHTITE 4H, EDTA ACID;Edathamil;EDETA B;edetic acid;Edetinsaure;EDTA;EDTA (chelating agent);EDTA ACID FORM;Endrate;ETHYLENE DINITRILO TETRAACETIC ACID;Ethylenediamine Tetra-Acetic Acid;Ethylenediamine-N,N,N’,N’-tetraacetic acid;Ethylenediaminetetraacetic acid;ETHYLENEDIAMINETETRAACETIC ACID (EDTA);ETHYLENEDIAMINETETRAACETIC ACID DISODIUM SALT;Ethylenediaminetetracetic acid;ETHYLENEDINITRILOTETRAACETIC ACID;Ethylene-N,N’-biscarboxymethyl-N,N’-diglycine;Gluma Cleanser;GLYCINE, N,N’-1,2-ETHANEDIYLBIS(N-(CARBOXYMETHYL));Glycine, N,N’-1,2-ethanediylbis[N-(carboxymethyl)-;Glycine, N,N’-1,2-ethanediylbis[N-(carboxymethyl)-;Glycine, N,N’-1,2-ethanediylbis[N-(carboxymethyl)-;Glycine,N,N’-1,2-ethanediylbis[N-(carboxymethyl)-,;Havidote;ICRF 185;Metaquest A;N,N’-1,2-Ethanediylbis[N-(carboxymethyl)glycine];N,N’-1,2-Ethanediyl-bis-N-(carboxymethyl)glycine;Nervanaid B acid;NSC 97243;NSC 97404;Nullapon B acid;Nullapon BF acid;Perma Kleer 50 acid;Quastal Special;Sequestrene AA;Sequestrene K 4;Sequestric acid;Sequestrol;Techrun DO;Titriplex;Titriplex II;Trilon BS;Trilon BW;Versene;WS;WS (chelating agent);YD 30;Zonon AO; Disodium dihydrogen ethylenediaminetetraacetate; 6381-92-6; ethylenediamine tetraacetic acid disodium salt; ETA Solution; Ethylenediaminetetraacetic acid disodium salt solution; Aceticacid, (ethylenedinitrilo)tetra-, disodium salt, dihydrate (8CI);Glycine,N,N’-1,2-ethanediylbis[N-(carboxymethyl)-, disodium salt, dihydrate (9CI);Disodium EDTA dihydrate;Disodium dihydrogen; ethylenediamine tetraacetatedihydrate; Disodium ethylenediaminetetraacetatedihydrate;Ethylenediaminetetraacetic acid disodium salt dihydrate;Ethylenediaminetetraacetic disodium;Edta disodium salt dihydrate; Edta 2 Na; EDTA disodium salt; 139-33-3; Disodium EDTA; Ethylenediaminetetraacetic acid disodium salt; Edta disodium; Disodium ethylenediaminetetraacetate; AK164289; EDTA 2Na; Disodium ethylenediaminetetraacetic acid; Disodium dihydrogen ethylenediaminetetraacetate; 6381-92-6; ethylenediamine tetraacetic acid disodium salt; ETA Solution; Ethylenediaminetetraacetic acid disodium salt solution; Edta 2 Na; EDTA 2NA; EDTA2NA; EDTA 2Na; edta 2na; Edta 2Na; EDTA-2Na; 2Na; edta 2na;
EDTA 2Na
Formula
C10H14N2Na2O8
CAS No. 139-33-3
EC No. 205-358-3
Synonyms INCI: Disodium EDTA ; Isodium dihydrogen ethylenediaminetetraacetate; Edetic acid disodium salt; EDTA disodium salt; (Ethylenedinitrilo)tetraacetic acid disodium salt; Disodium Edetate
Ethylenediaminetetraacetic acid disodium salt (EDTA 2Na)
EDTA 2Na (ethylenediaminetetracetic acid disodium) is a chelating agent, used to sequester and decrease the reactivity of metal ions that may be present in many industrial and personal care products.
Industrial applications:
EDTA 2Na is used in cleaners, detergent, fertilizers, fixer solution for development of colour film, water cleaner and pH modifier. It is also used in redox reaction for the polymerization of butyl benzene rubber, it is used as part of activator for the control of polymerization speed.
Personal Care:
EDTA 2Na is used in Cosmetics to increase effectiveness and improve stability of bar and solid soaps, bath preparations; creams, oils, hair care products and many other personal care formulations.
Unfortunately, EDTA 2Na is difficultly biodegradable and hazardous for water.
Connect Chemicals offer valid and effective alternatives to EDTA Na2, please see the product pages of H-Quest and GLDA, both 100% biodegradable and obtained from bio-feedstock.
Packaging & Shelf Life:
bags 25 kg net
Under proper storage conditions the shelf life is 36 months
Health & Safety:
Detailed information on the product described can be found in our relevant Health and Safety Information (Material Safety Data Sheet).
Ethylenediaminetetraacetic acid
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This article is about the chemical. For the medication, see Sodium calcium edetate.
Ethylenediaminetetraacetic acid
Skeletal formula of ethylenediaminetetraacetic acid
Names
Systematic IUPAC name
2,2′,2″,2‴-(Ethane-1,2-diyldinitrilo)tetraacetic acid[1]
Other names
EthyleneDiamineTetraAcetic acid
N,N′-Ethane-1,2-diylbis[N-(carboxymethyl)glycine][1]
Diaminoethane-tetraacetic acid
Edetic acid (conjugate base edetate) (INN, USAN)
Versene
Identifiers
CAS Number
60-00-4 (free acid) ☑
6381-92-6 (dihydrate disodium salt) ☒
3D model (JSmol)
Interactive image
Abbreviations EDTA 2Na, H4EDTA
Beilstein Reference
1716295
ChEBI
CHEBI:42191 ☑
ChEMBL
ChEMBL858 ☑
ChemSpider
5826 ☑
DrugBank
DB00974 ☑
ECHA InfoCard 100.000.409
EC Number
200-449-4
Gmelin Reference
144943
KEGG
D00052 ☑
MeSH Edetic+Acid
PubChem CID
6049
RTECS number
AH4025000
UNII
9G34HU7RV0 ☑
UN number 3077
CompTox Dashboard (EPA)
DTXSID6022977 Edit this at Wikidata
InChI[show]
SMILES[show]
Properties
Chemical formula
C10H16N2O8
Molar mass 292.244 g·mol-1
Appearance Colourless crystals
Density 0.860 g cm-3 (at 20 °C)
log P -0.836
Acidity (pKa) 2.0, 2.7, 6.16, 10.26[2]
Thermochemistry
Std enthalpy of
formation (ΔfH⦵298)
-1765.4 to -1758.0 kJ mol-1
Std enthalpy of
combustion (ΔcH⦵298)
-4461.7 to -4454.5 kJ mol-1
Pharmacology
ATC code
S01XA05 (WHO) V03AB03 (WHO) (salt)
Routes of
administration
Intramuscular
Intravenous
Hazards
GHS pictograms GHS07: Harmful
GHS Signal word Warning
GHS hazard statements
H319
GHS precautionary statements
P305+351+338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
010
Lethal dose or concentration (LD, LC):
LD50 (median dose)
1000 mg/kg (oral, rat)[3]
Related compounds
Related alkanoic acids
Daminozide
Octopine
Related compounds
Triethylenetetramine
Tetraacetylethylenediamine
PMDTA
Bis-tris propane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Ethylenediaminetetraacetic acid (EDTA 2Na), also known by several other names, is a chemical used for both industrial and medical purposes. It was synthesized for the first time in 1935 by Ferdinand Münz.[4]
Ethylenediaminetetraacetic acid (EDTA), also known by several other names, is a chemical used for both industrial and medical purposes.
It is an aminopolycarboxylic acid and a colourless, water-soluble solid. Its conjugate base is ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate (“six-toothed”) ligand and chelating agent, i.e., its ability to “sequester” metal ions such as Ca2+ and Fe3+. After being bound by EDTA into a metal complex, metal ions remain in solution but exhibit diminished reactivity. EDTA is produced as several salts, notably disodium EDTA and calcium disodium EDTA.
Uses of EDTA
Industry
In industry, EDTA is mainly used to sequester 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 “chlorine-free bleaching”. In a similar manner, EDTA is added to some food as a preservative or stabilizer to prevent catalytic oxidative decoloration, which is catalyzed by metal ions. In soft drinks containing ascorbic acid and sodium benzoate, EDTA mitigates formation of benzene (a carcinogen).
The reduction of water hardness in laundry applications and the dissolution of scale in boilers both rely on EDTA and related complexants to bind Ca2+, Mg2+, as well as other metal ions. Once bound to EDTA, these metal centers tend not to form precipitates or to interfere with the action of the soaps and detergents. For similar reasons, cleaning solutions often contain EDTA.
The solubilization of ferric ions, at or below near neutral pH can be accomplished using EDTA. This property is useful in agriculture including hydroponics. However, given the pH dependence of ligand formation, EDTA is not helpful for improving Fe solubility in above neutral soils.[5] Otherwise, at near-neutral pH and above, iron(III) forms insoluble salts, which are less bioavailable to susceptible plant species. Aqueous [Fe(edta)]- is used for removing (“scrubbing”) hydrogen sulfide from gas streams. This conversion is achieved by oxidizing the hydrogen sulfide to elemental sulfur, which is non-volatile.
In this application, the ferric center is reduced to its ferrous derivative, which can then be reoxidized by air. In similar manner, nitrogen oxides are removed from gas streams using [Fe(edta)]2-. The oxidizing properties of [Fe(edta)]- are also exploited in photography, where it is used to solubilize silver particles.
EDTA was used in the separation of the lanthanide metals by ion-exchange chromatography. Perfected by F.H. Spedding et al. in 1954, the method relies on the steady increase in stability constant of the lanthanide EDTA complexes with atomic number. Using sulfonated polystyrene beads and copper(II) as a retaining ion, EDTA causes the lanthanides to migrate down the column of resin while separating into bands of pure lanthanide. The lanthanides elute in order of decreasing atomic number. Due to the expense of this method, relative to counter-current solvent extraction, ion-exchange is now used only to obtain the highest purities of lanthanide (typically greater than 4N, 99.99%).
Cosmetic
In shampoos, cleaners, and other personal care products, EDTA salts are used as a sequestering agent to improve their stability in air.
Medicine
Main article: Sodium calcium edetate
A specific salt of EDTA, known as sodium calcium edetate, is used to bind metal ions in the practice of chelation therapy, e.g., for treating mercury and lead poisoning. It is used in a similar manner to remove excess iron from the body. This therapy is used to treat the complication of repeated blood transfusions, as would be applied to treat thalassaemia.
Dentists and endodontists use EDTA solutions to remove inorganic debris (smear layer) and lubricate the canals in endodontics. This procedure helps prepare root canals for obturation. Furthermore, EDTA solutions with the addition of a surfactant loosen up calcifications inside a root canal and allow instrumentation (canals shaping) and facilitate apical advancement of a file in a tight/calcified root canal towards the apex.
It serves as a preservative (usually to enhance the action of another preservative such as benzalkonium chloride or thiomersal) in ocular preparations and eyedrops.
In evaluating kidney function, the complex [Cr(edta)]- is administered intravenously and its filtration into the urine is monitored. This method is useful for evaluating glomerular filtration rate.
EDTA is used extensively in the analysis of blood. It is an anticoagulant for blood samples for CBC/FBEs.
EDTA is a slime dispersant, and has been found to be highly effective in reducing bacterial growth during implantation of intraocular lenses (IOLs).
EDTA 2Na is an aminopolycarboxylic acid and a colorless, water-soluble solid.EDTA 2Nas conjugate base is ethylenediaminetetraacetate. EDTA 2Na is widely used to dissolve limescale. EDTA 2Na’s usefulness arises because of its role as a hexadentate (“six-toothed”) ligand and chelating agent, i.e., its ability to sequester metal ions such as Ca2+ and Fe3+. After being bound by EDTA 2Na into a metal complex, metal ions remain in solution but exhibit diminished reactivity. EDTA 2Na is produced as several salts, notably disodium EDTA 2Na, calcium disodium EDTA 2Na, and tetrasodium EDTA 2Na (typically as the hydrate).
Uses
Industry
In industry, EDTA 2Na is mainly used to sequester 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 2Na inhibits the ability of metal ions, especially Mn2+, from catalyzing the disproportionation of hydrogen peroxide, which is used in chlorine-free bleaching. In a similar manner, EDTA 2Na is added to some food as a preservative or stabilizer to prevent catalytic oxidative decoloration, which is catalyzed by metal ions.[5] In soft drinks containing ascorbic acid and sodium benzoate, EDTA 2Na mitigates formation of benzene (a carcinogen).[6]
The reduction of water hardness in laundry applications and the dissolution of scale in boilers both rely on EDTA 2Na and related complexants to bind Ca2+, Mg2+, as well as other metal ions. Once bound to EDTA 2Na, these metal centers tend not to form precipitates or to interfere with the action of the soaps and detergents. For similar reasons, cleaning solutions often contain EDTA 2Na. In a similar manner EDTA 2Na is used in the cement industry for the determination of free lime and free magnesia in cement and clinkers.[7][page needed]
The solubilization of Fe3+ ions at or below near neutral pH can be accomplished using EDTA 2Na. This property is useful in agriculture including hydroponics. However, given the pH dependence of ligand formation, EDTA 2Na is not helpful for improving iron solubility in above neutral soils.[8] Otherwise, at near-neutral pH and above, iron(III) forms insoluble salts, which are les bioavailable to susceptible plant species. Aqueous [Fe(EDTA 2Na)]- is used for removing (“scrubbing”) hydrogen sulfide from gas streams. This conversion is achieved by oxidizing the hydrogen sulfide to elemental sulfur, which is non-volatile:
2 [Fe(EDTA)]- + H2S → 2 [Fe(EDTA)]2- + S + 2 H+
In this application, the iron(III) center is reduced to its iron(II) derivative, which can then be reoxidized by air. In similar manner, nitrogen oxides are removed from gas streams using [Fe(edta)]2-. The oxidizing properties of [Fe(edta)]- are also exploited in photography, where it is used to solubilize silver particles.[9]
EDTA 2Na was used in separation of the lanthanide metals by ion-exchange chromatography. Perfected by F. H. Spedding et al. in 1954,[citation needed] the method relies on the steady increase in stability constant of the lanthanide EDTA 2Na complexes with atomic number. Using sulfonated polystyrene beads and Cu2+ as a retaining ion, EDTA 2Na causes the lanthanides to migrate down the column of resin while separating into bands of pure lanthanides. The lanthanides elute in order of decreasing atomic number. Due to the expense of this method, relative to countercurrent solvent extraction, ion exchange is now used only to obtain the highest purities of lanthanides (typically greater than 99.99%).[citation needed]
Medicine
Main article: Sodium calcium edetate
A specific salt of EDTA 2Na, known as sodium calcium edetate, is used to bind metal ions in the practice of chelation therapy, such as for treating mercury and lead poisoning.[10] It is used in a similar manner to remove excess iron from the body. This therapy is used to treat the complication of repeated blood transfusions, as would be applied to treat thalassaemia.
Dentists and endodontists use EDTA 2Na solutions to remove inorganic debris (smear layer) and lubricate the root canals in endodontics. This procedure helps prepare root canals for obturation. Furthermore, EDTA 2Na solutions with the addition of a surfactant loosen up calcifications inside a root canal and allow instrumentation (canal shaping) and facilitate apical advancement of a file in a tight or calcified root canal towards the apex.
It serves as a preservative (usually to enhance the action of another preservative such as benzalkonium chloride or thiomersal) in ocular preparations and eyedrops.
In evaluating kidney function, the chromium(III) complex [Cr(edta)]- (as radioactive chromium-51 (51Cr)) is administered intravenously and its filtration into the urine is monitored. This method is useful for evaluating glomerular filtration rate (GFR) in nuclear medicine.[11]
EDTA 2Na is used extensively in the analysis of blood. It is an anticoagulant for blood samples for CBC/FBEs, where the EDTA 2Na chelates the calcium present in the blood specimen, arresting the coagulation process and preserving blood cell morphology.[12] Tubes containing EDTA 2Na are marked with lavender or pink tops.[13] EDTA 2Na is also in tan top tubes for lead testing and can be used in royal blue top tubes for trace metal testing.[13]
EDTA 2Na is a slime dispersant, and has been found to be highly effective in reducing bacterial growth during implantation of intraocular lenses (IOLs).[14]
Alternative medicine
Some alternative practitioners believe EDTA 2Na acts as an antioxidant, preventing free radicals from injuring blood vessel walls, therefore reducing atherosclerosis.[citation needed] These ideas are unsupported by scientific studies, and seem to contradict some currently accepted principles.[15] The U.S. FDA has not approved it for the treatment of atherosclerosis.[16]
Cosmetics
In shampoos, cleaners, and other personal care products, EDTA 2Na salts are used as a sequestering agent to improve their stability in air.[17]
Laboratory applications
In the laboratory, EDTA 2Na is widely used for scavenging metal ions: In biochemistry and molecular biology, ion depletion is commonly used to deactivate metal-dependent enzymes, either as an assay for their reactivity or to suppress damage to DNA, proteins, and polysaccharides.[18] EDTA 2Na also acts as a selective inhibitor against dNTP hydrolyzing enzymes (Taq polymerase, dUTPase, MutT),[19] liver arginase[20] and horseradish peroxidase[21] independently of metal ion chelation. These findings urge the rethinking of the utilization of EDTA 2Na as a biochemically inactive metal ion scavenger in enzymatic experiments. In analytical chemistry, EDTA 2Na is used in complexometric titrations and analysis of water hardness or as a masking agent to sequester metal ions that would interfere with the analyses.
EDTA 2Na finds many specialized uses in the biomedical labs, such as in veterinary ophthalmology as an anticollagenase to prevent the worsening of corneal ulcers in animals. In tissue culture EDTA 2Na is used as a chelating agent that binds to calcium and prevents joining of cadherins between cells, preventing clumping of cells grown in liquid suspension, or detaching adherent cells for passaging. In histopathology, EDTA 2Na can be used as a decalcifying agent making it possible to cut sections using a microtome once the tissue sample is demineralised. EDTA 2Na is also known to inhibit a range of metallopeptidases, the method of inhibition occurs via the chelation of the metal ion required for catalytic activity.[22] EDTA 2Na can also be used to test for bioavailability of heavy metals in sediments. However, it may influence the bioavailability of metals in solution, which may pose concerns regarding its effects in the environment, especially given its widespread uses and applications.
Side effects
EDTA 2Na exhibits low acute toxicity with LD50 (rat) of 2.0 g/kg to 2.2 g/kg.[9] It has been found to be both cytotoxic and weakly genotoxic in laboratory animals. Oral exposures have been noted to cause reproductive and developmental effects.[17] The same study[17] also found that both dermal exposure to EDTA 2Na in most cosmetic formulations and inhalation exposure to EDTA 2Na in aerosolized cosmetic formulations would produce exposure levels below those seen to be toxic in oral dosing studies.
Synthesis
The compound was first described in 1935 by Ferdinand Münz, who prepared the compound from ethylenediamine and chloroacetic acid.[23] Today, EDTA 2Na is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde, and sodium cyanide.[24] This route yields the tetrasodium EDTA 2Na, which is converted in a subsequent step into the acid forms:
H2NCH2CH2NH2 + 4 CH2O + 4 NaCN + 4 H2O → (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 NH3
(NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 HCl → (HO2CCH2)2NCH2CH2N(CH2CO2H)2 + 4 NaCl
This process is used to produce about 80,000 tonnes of EDTA 2Na each year. Impurities cogenerated by this route include glycine and nitrilotriacetic acid; they arise from reactions of the ammonia coproduct.[9]
Nomenclature
To describe EDTA 2Na and its various protonated forms, chemists distinguish between EDTA 2Na4-, the conjugate base that is the ligand, and H4EDTA 2Na, the precursor to that ligand. At very low pH (very acidic conditions) the fully protonated H6EDTA2+ form predominates, whereas at very high pH or very basic condition, the fully deprotonated EDTA4- form is prevalent. In this article, the term EDTA is used to mean H4-xEDTAx-, whereas in its complexes EDTA4- stands for the tetraanion ligand.
Coordination chemistry principles
Metal-EDTA chelate as found in Co(III) complexes.
Structure of [Fe(EDTA)(H2O)]-, showing that the EDTA4- ligand does not fully encapsulate Fe(III), which is seven-coordinate.[25]
In coordination chemistry, EDTA4- is a member of the aminopolycarboxylic acid family of ligands. EDTA4- usually binds to a metal cation through its two amines and four carboxylates. Many of the resulting coordination compounds adopt octahedral geometry. Although of little consequence for its applications, these octahedral complexes are chiral. The cobalt(III) anion [Co(EDTA)]- has been resolved into enantiomers.[26] Many complexes of EDTA4- adopt more complex structures due to either the formation of an additional bond to water, i.e. seven-coordinate complexes, or the displacement of one carboxylate arm by water. The iron(III) complex of EDTA 2Na is seven-coordinate.[27] Early work on the development of EDTA 2Na was undertaken by Gerold Schwarzenbach in the 1940s.[28] EDTA 2Na forms especially strong complexes with Mn(II), Cu(II), Fe(III), Pb(II) and Co(III).[29][page needed]
Several features of EDTA 2Na’s complexes are relevant to its applications. First, because of its high denticity, this ligand has a high affinity for metal cations:
[Fe(H2O)6]3+ + H4EDTA ⇌ [Fe(EDTA)]- + 6 H2O + 4 H+ Keq = 1025.1
Written in this way, the equilibrium quotient shows that metal ions compete with protons for binding to EDTA. Because metal ions are extensively enveloped by EDTA 2Na, their catalytic properties are often suppressed. Finally, since complexes of EDTA4- are anionic, they tend to be highly soluble in water. For this reason, EDTA 2Na is able to dissolve deposits of metal oxides and carbonates.
The pKa values of free EDTA 2Na are 0, 1.5, 2, 2.66 (deprotonation of the four carboxyl groups) and 6.16, 10.24 (deprotonation of the two amino groups).[30]
Environmental fate
Abiotic degradation
EDTA 2Na is in such widespread use that questions have been raised whether it is a persistent organic pollutant. While EDTA 2Na serves many positive functions in different industrial, pharmaceutical and other avenues, the longevity of EDTA 2Na can pose serious issues in the environment. The degradation of EDTA 2Na is slow. EDTA 2Na mainly occurs abiotically in the presence of sunlight.[31]
The most important process for the elimination of EDTA 2Na from surface waters is direct photolysis at wavelengths below 400 nm.[32] Depending on the light conditions, the photolysis half-lives of iron(III) EDTA 2Na in surface waters can range as low as 11.3 minutes up to more than 100 hours.[33] Degradation of FeEDTA, but not EDTA 2Na itself, produces iron complexes of the triacetate (ED3A), diacetate (EDDA), and monoacetate (EDMA) – 92% of EDDA and EDMA biodegrades in 20 hours while ED3A displays significantly higher resistance. Many environmentally-abundant EDTA 2Na species (such as Mg2+ and Ca2+) are more persistent.
Biodegradation
In many industrial wastewater treatment plants, EDTA 2Na elimination can be achieved at about 80% using microorganisms.[34] Resulting byproducts are ED3A and iminodiacetic acid (IDA) – suggesting that both the backbone and acetyl groups were attacked. Some microorganisms have even been discovered to form nitrates out of EDTA 2Na, but they function optimally at moderately alkaline conditions of pH 9.0-9.5.[35]
Several bacterial strains isolated from sewage treatment plants efficiently degrade EDTA 2Na. Specific strains include Agrobacterium radiobacter ATCC 55002[36] and the sub-branches of Proteobacteria like BNC1, BNC2,[37] and strain DSM 9103.[38] The three strains share similar properties of aerobic respiration and are classified as gram-negative bacteria. Unlike photolysis, the chelated species is not exclusive to iron(III) in order to be degraded. Rather, each strain uniquely consumes varying metal-EDTA 2Na complexes through several enzymatic pathways. Agrobacterium radiobacter only degrades Fe(III) EDTA 2Na[37] while BNC1 and DSM 9103 are not capable of degrading iron(III) EDTA 2Na and are more suited for calcium, barium, magnesium and manganese(II) complexes.[39] EDTA 2Na complexes require dissociation before degradation.
Alternatives to EDTA 2Na
Interest in environmental safety has raised concerns about biodegradability of aminopolycarboxylates such as EDTA 2Na. These concerns incentivize the investigation of alternative aminopolycarboxylates.[31] Candidate chelating agents include nitrilotriacetic acid (NTA), iminodisuccinic acid (IDS), polyaspartic acid, S,S-ethylenediamine-N,N′-disuccinic acid (EDDS), methylglycinediacetic acid (MGDA), and L-Glutamic acid N,N-diacetic acid, tetrasodium salt (GLDA).[40]
Iminodisuccinic acid (IDS)
Commercially used since 1998, iminodisuccinic acid (IDS) biodegrades by about 80% after only 7 days. IDS binds to calcium exceptionally well and forms stable compounds with other heavy metal ions. In addition to having a lower toxicity after chelation, IDS is degraded by Agrobacterium tumefaciens (BY6), which can be harvested on a large scale. The enzymes involved, IDS epimerase and C-N lyase, do not require any cofactors.[41]
Polyaspartic acid
Polyaspartic acid, like IDS, binds to calcium and other heavy metal ions. It has many practical applications including corrosion inhibitors, wastewater additives, and agricultural polymers. A Polyaspartic acid-based laundry detergent was the first laundry detergent in the world to receive the EU flower ecolabel.[42]
S,S-Ethylenediamine-N,N′-disuccinic acid (EDDS)
The S,S isomer of EDTA 2Na, ethylenediamine-N,N′-disuccinic acid (EDDS) is readily biodegradable and exhibits a high rate biodegradation.[43]
Methylglycinediacetic acid (MGDA)
Trisodium dicarboxymethyl alaninate, also known as methylglycinediacetic acid (MGDA), has a high rate of biodegradation at over 68%, but unlike many other chelating agents can degrade without the assistance of adapted bacteria. Additionally, unlike EDDS or IDS, MGDA can withstand higher temperatures while maintaining a high stability as well as the entire pH range.[citation needed] MGDA has been shown to be an effective chelating agent, with a capacity for mobilization comparable with that of Nitrilotriacetic acid (NTA), with application to water for industrial use and for the removal of calcium oxalate from urine from patients with kidney stones.[44]
Methods of detection and analysis
The most sensitive method of detecting and measuring EDTA 2Na in biological samples is selected reaction monitoring capillary electrophoresis mass spectrometry (SRM-CE/MS), which has a detection limit of 7.3 ng/mL in human plasma and a quantitation limit of 15 ng/mL.[45] This method works with sample volumes as small as 7-8 nL.[45]
EDTA 2Na has also been measured in non-alcoholic beverages using high performance liquid chromatography (HPLC) at a level of 2.0 μg/mL.
EDTA 2Na 2Na
( Ethylenediaminetetraacetic Acid, disodium Salt / EDTA 2Na 2Na )
Molecular Formula C10H14N2O8Na2王2H2O
Molecular Weight 372.2
CAS No 6381-92-6
Physical Properties
Appearance ……………. White Crystalline Powder
Bulk Density ………….. approx. 0.63g/cm3
Solubility in Water …. 10.8g/100m坐 at 22◥C
23.6g/100m坐 at 80◥C
Specification
Purity ……………….. 98% up
pH of 5% aqueous solution ………….. 4.4 ~ 4.7
Chelating Value (as mg CaCO3/g) … 260 up
Environmental Aspects
Biodegradability ……….. difficult
C.O.D. ……………………. approx. 560mg/g
Application
in the detergent industry as stabilizer
in the chemical industry as metal carrier in redox system
in the cosmetic industry as stabilizer for preparation
in the printing industry to control hardness and as stabilizer
Packing
20kgs net in multiply paper bag with value and inside polyethylene bag
16MT/FCL with Pallet
17MT/FCL without Pallet
Storage
Store on a dry place
Opened bags must be closed again properly.
Safety Precautions in Handling
do not inhale or ingest, avoid contacting with the skin and protest the eye from splashes.
Wear safety goggles, glovers and a mask of there is a risk of repeated contact.
Wash thoroughly after handling
First-aid Measures
Skin contact : wash with plenty of water
Splashes in the eyes: wash with water at low pressure then with a neutral solution of boric acid. Consult an ophthalmologist.
Ingestion : make the victim vomit if he/she is conscious and consult a doctor if necessary
Disodium EDTA 2Na, 99% – EDTA 2Na
Ethylene diamine tetraacetic acid disodium salt (EDTA 2NA)
EDTA-4NA2_img2Molecular fomula: C10H14N2O8Na2•2H2O
Molecular weight: M=372.24
CAS No. : 6381-92-6
Properties: white crystal powder soluble in water, and a variety of metal ion chelation.
Disodium EDTA 2Na Chelation binds to metal ions which inactivates them.
The binding of metal ions helps prevent the deterioration of cosmetics and personal care products.
It also helps to maintain clarity, protect fragrance compounds, and prevent rancidity.
By binding with metal ions, EDTA 2NA prevents metals from being deposited onto hair and skin.
Specifications ;
Test Item
Standard Specification
Quality Standard
Q/24SJK01-2009
Purity
99% Min.
Chloride(Cl)%
0.01% Max.
Sulfate(SO4)%
0.05% Max.
Metal chelate(Pb)%
0.001% Max.
Iron(Fe)%
0.001% Max.
Chelate: mgCaCO3/g
256 Min.
pH Value
4.0-5.0
Appearance
White Crystalline Powder
Packing: 25KG/bag , or according to the customers’ requirements
Storage: Stored in the dry and ventilated inside storeroom, prevent direct sunlight, slightly pile and put down.
Applications :
Cosmetics
Personal care (soap, shampoo)
Oil industry (anti-caking agent)
Food additives
Textile Manufacture
EDTA 2Na
EDTA 2Na (Titriplex III) Pur. Gr. 5 kg BCT Plastik
Teknik Özellikleri
C10H14N2Na2O8.2H2O
M = 372,24 g/mol
Erime: 252 °C
CAS [6381-92-6]
EC 205-358-3
SINIFI:DIKKAT H332 P271 – P260 – P312 – P304+P340
PARAMETRELER SPESFKASYON DEERLER
Safiyet : >= 99,0%
EDTA 2Na(Anhidrus)
: >=89,0%
PH (% 1,H2O,25 C)
: 4,0-5,0
EDTA 2Na (Ethylenediaminetetraacetic acid)
EDTA 2Na Nedir?
EDTA 2Na bileii Etilendiamin tetraasetik asit’in ksaltmasidir. EDTA 2Na polyamino karboksilik asid bileiidir.
Genel formülü ise [CH2N(CH2COOH)2]2 eklindedir.
Yapsal formülü için;
EDTA 2Na’nn Kimyasal Özellikleri
CAS No: 60-00-4
Molekül Formülü: C10H16N2O8
Molekül Arl: 292.24 g.mol-1
Younluu: 0,86 g/cm3
Erime noktas: 240 °C
Asidite;
pK1=0.0 (CO2H) (µ=1.0)
pK2=1.5 (CO2H) (µ=0.1)
pK3=2.00 (CO2H) (µ=0.1)
pK4=2.69 (CO2H) (µ=0.1)
pK5=6.13 (NH+) (µ=0.1)
pK6=10.37 (NH+) (µ=0.1)
EDTA 2Na’nn Kefi
EDTA 2Na ilk olarak Ferdinand Munz tarafndan tanmlanmtr. Munz, EDTA 2Na’nn kefini etilendiamin ve klorasetik asit çözeltilerinden elde etmitir.
H2NCH2CH2NH2 + 4 CH2O + 4 NaCN + 4 H2O → (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 NH3
(NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 HCl → (HO2CCH2)2NCH2CH2N(CH2CO2H)2 + 4 NaCl
Poliamino karboksilik asid grubundan olan EDTA 2Na’nn kimyasal yapsna bakldnda 2 amino 4 karboksil ligand vardr. EDTA 2Na metal iyonlarna kar yüksek afinite gösterir.
[Fe(H2O)6]3+ + H4EDTA {displaystyle rightleftharpoons }{displaystyle rightleftharpoons } [Fe(EDTA)]-+ 6 H2O + 4 H+ (Keq = 1025.1)
EDTA 2Na’nn Laboratuvarda Kullanm
EDTA 2Na laboratuvarda metal iyonlarn tutmak için kullanlr. Biyokimya ve moleküler biyoloji iyon tüketici olarak enzimlere kar kullanlr. Analitik kimya da kompleksometrik titrasyon, Su sertlii maskeleyici ajanlar analizelerinde kullanlr.
EDTA 2Na, bir aminopolikarboksilik asit ve renksiz, suda çözünür bir katdr. EDTA 2N konjugat baz, etilendiamintetraasetattr. EDTA 2Na kireci eritmek için yaygn olarak kullanlr. EDTA 2Na’nn kullanll, bir heksadentat (“alt dili”) ligand ve kenetleme maddesi, yani Ca2 + ve Fe3 + gibi metal iyonlarn sekestre etme kabiliyeti nedeniyle ortaya çkar. EDTA 2Na ile bir metal kompleksine balandktan sonra, metal iyonlar çözelti içinde kalr, ancak azalan reaktivite sergiler. EDTA 2Na, çeitli tuzlar, özellikle disodyum EDTA 2Na, kalsiyum disodyum EDTA 2Na ve tetrasodyum EDTA 2Na (tipik olarak hidrat olarak) olarak üretilir.
Kullanmlar
sanayi
Endüstride, EDTA 2Na esas olarak sulu çözeltideki metal iyonlarn ayrmak için kullanlr. Tekstil endüstrisinde, metal iyonu safszlklarnn boyal ürünlerin renklerini deitirmesini önler. Kat hamuru ve kat endüstrisinde EDTA 2Na, metal iyonlarnn, özellikle Mn2 + ‘nn, klorsuz aartmada kullanlan hidrojen peroksit orantszln katalizlemesini engeller. Benzer bir ekilde, EDTA 2Na, metal iyonlar tarafndan katalizlenen katalitik oksidatif renklenmeyi önlemek için baz yiyeceklere koruyucu veya stabilizatör olarak eklenir. [5] Askorbik asit ve sodyum benzoat içeren alkolsüz içeceklerde EDTA 2Na, benzen (kanserojen) oluumunu azaltr. [6]
Çamar ykama uygulamalarnda su sertliinin azaltlmas ve kazanlarda kirecin çözülmesi, Ca2 +, Mg2 + ve dier metal iyonlarn balamak için EDTA 2Na ve ilgili komplekslere dayanr. EDTA 2Na’ya balandktan sonra, bu metal merkezler çökelti oluturma veya sabun ve deterjanlarn etkisine müdahale etme eilimi göstermez. Benzer nedenlerle, temizleme solüsyonlar genellikle EDTA 2Na içerir. Benzer ekilde EDTA 2Na, çimento endüstrisinde çimento ve klinkerlerde serbest kireç ve serbest magnezyumun belirlenmesi için kullanlr. [7] [sayfa gerekli]
Fe3 + iyonlarnn nötr pH’a yakn veya bunun altnda çözünürlüü EDTA 2Na kullanlarak yaplabilir. Bu özellik, hidroponik dahil tarmda yararldr. Bununla birlikte, ligand oluumunun pH bamll göz önüne alndnda, EDTA 2Na yukardaki nötr topraklarda demir çözünürlüünü arttrmak için yararl deildir. [8] Aksi takdirde, nötre yakn pH ve üzerinde, demir (III) duyarl bitki türlerine biyoyararlanabilen çözünmez tuzlar oluturur. Sulu [Fe (EDTA 2Na)] – hidrojen sülfürün gaz aklarndan uzaklatrlmas (“frçalanmas”) için kullanlr. Bu dönüüm, hidrojen sülfürün uçucu olmayan element sülfüre oksitlenmesiyle elde edilir:
2 [Fe (EDTA)] – + H2S → 2 [Fe (EDTA)] 2- + S + 2H +
Bu uygulamada, demir (III) merkezi, demir (II) türevine indirgenir ve bu daha sonra hava ile yeniden oksitlenebilir. Benzer ekilde, azot oksitler [Fe (edta)] 2- kullanlarak gaz akmlarndan uzaklatrlr. [Fe (edta)] – ‘nn oksitleyici özellikleri, gümü parçacklarn çözündürmek için kullanld fotorafçlkta da kullanlr. [9]
EDTA 2Na, lantanid metallerinin iyon deiim kromatografisiyle ayrlmasnda kullanld. F. H. Spedding ve ark. 1954’te [alnt gerekli] yöntem, atom numaras olan lantanid EDTA 2Na komplekslerinin kararllk sabitinde sürekli bir arta dayanr. Bir tutma iyonu olarak sülfonatl polistiren tanecikleri ve Cu2 + kullanlarak EDTA 2Na, lantanitlerin saf lantanit bantlarna ayrlrken reçine kolonuna doru göç etmesine neden olur. Lantanidler, azalan atom saysna göre elüte edilir. Bu yöntemin maliyeti nedeniyle, ters akm çözücü ekstraksiyonuna göre, iyon deiimi artk sadece en yüksek lantanit saflklarn (tipik olarak% 99.99’dan daha fazla) elde etmek için kullanlmaktadr.
Etilen diaminetetraasetik asit (EDTA), dier birçok isimle de bilinir; hem endüstriyel hem de tbbi amaçlar için kullanlan bir kimyasaltr.
Bir aminopolikarboksilik asit ve renksiz, suda çözünen bir katdr. Elenik taban etilendiamintetraasetattr. Kireç çözeltisini çözmek için yaygn olarak kullanlr. Kullanll, bir alt katl (“alt-dili”) ligand ve kenetleme maddesi rolü, yani Ca2 + ve Fe3 + gibi metal iyonlarn “smsk tutma” özellii nedeniyle ortaya çkar. EDTA ile bir metal kompleksine balandktan sonra, metal iyonlar solüsyon halinde kalr, ancak azalan reaktivite gösterirler. EDTA çeitli tuzlar, özellikle disodyum EDTA ve kalsiyum disodyum EDTA olarak üretilir.
EDTA’nn Kullanm
Sanayi
Endüstride, EDTA esas olarak sulu çözeltide metal iyonlarn tutmak için kullanlr. Tekstil endüstrisinde, metal iyonu yabanc maddelerinin boyal ürünlerin renklerini deitirmesini önler. Kat hamuru ve kat endüstrisinde, EDTA, metal iyonlarnn, özellikle Mn2 + ‘nn, “klor içermeyen aartma” da kullanlan hidrojen peroksit orantszlatrmasn katalize etme yetisini engeller. Benzer bir ekilde, EDTA, metal iyonlaryla katalize edilen katalitik oksidatif renksizlemeyi önlemek için bir gda maddesine bir koruyucu veya stabilizatör olarak ilave edilir. Askorbik asit ve sodyum benzoat içeren alkolsüz içeceklerde EDTA benzen oluumunu hafifletir (bir karsinojen).
Çamar ykama uygulamalarnda su sertliinin azaltlmas ve kazanlarda ölçein çözünmesi hem EDTA’ya hem de ilgili kompleks yapclara Ca2 +, Mg2 + ve dier metal iyonlarn balamaya dayanmaktadr. EDTA’ya balandktan sonra, bu metal merkezleri çökeltiler oluturmamakta veya sabun ve deterjanlara müdahale etme eilimindedir. Benzer nedenlerden ötürü, temizleme çözeltileri genellikle EDTA içerir.
Demir iyonlarnn nötr pH deerinde veya altnda çözünürlüü, EDTA kullanlarak gerçekletirilebilir. Bu özellik, suda yaayanlar da dahil olmak üzere tarmda yararldr. Bununla birlikte, ligand oluumunun pH bamll göz önüne alndnda, EDTA, nötr topraklarda Fe çözünürlüünü arttrmak için yararl deildir. [5] Aksi halde, neredeyse nötr pH ve üzeri demir (III), hassas bitki türleri için daha az biyolojik olarak bulunabilen çözünmez tuzlar oluturur. Sulu [Fe (edta)] – gaz akmlarndan hidrojen sülfidin uzaklatrlmas için (“ovma”) kullanlr. Bu dönüüm, hidrojen sülfidi, uçucu olmayan elemental kükürt içine oksitleyerek gerçekletirilir.
Bu uygulamada ferrik merkez demir türevine indirgenir ve daha sonra hava ile yeniden okside edilebilir. Benzer ekilde azot oksitler, gaz akmlarndan [Fe (edta)] 2- kullanlarak uzaklatrlr. [Fe (edta)] ‘nn oksitleyici özellikleri – gümü parçacklar çözündürmek için kullanld fotoraflarda da istismar edilmektedir.
EDTA, iant deiim kromatografisi ile lantanid metallerin ayrlmasnda kullanlmtr. F.H. Spedding ve dierleri tarafndan mükemmelletirildi. 1954’te yöntem, atom numarasyla lantanid EDTA komplekslerinin kararllk sabitinin istikrarl bir ekilde artmasna dayanmaktadr. EDTA, szdrmaz polistiren boncuklar ve bakr (II) tutma iyonu olarak kullanldnda, lantanidlerin saf lantanit bantlarna ayrlrken reçinenin kolonundan aaya doru gitmesine neden olur. Lantanidler azalan atomik say srasna göre elüte edilir. Kar akm solvent özütlemesine göre, bu yöntemin masrafndan dolay, iyon deiimi, sadece en yüksek saflkta lantanit elde etmek için (genellikle 4N’den büyük,% 99.99) kullanlmaktadr.
Kozmetik
ampuanlar, temizleyiciler ve dier kiisel bakm ürünlerinde, EDTA tuzlar havadaki kararlln artrmak için bir kenetleme maddesi olarak kullanlr.
Tp
Ana madde: Sodyum kalsiyum edetat
EDTA’nn, sodyum kalsiyum edetat olarak bilinen spesifik bir tuzu, örnein cva ve kurun zehirlenmesinin tedavisinde elat tedavisi uygulamasnda metal iyonlarn balamak için kullanlr. Vücudun fazla demirini almak için benzer ekilde kullanlr. Talasemi tedavisinde olduu gibi, bu tekrarlanan kan nakli komplikasyonlarnn tedavisinde kullanlr.
Di hekimleri ve endodontistler, endodontide inorganik enkazlar (leke tabakas) kaldrmak ve kanallar yalamak için EDTA solüsyonlarn kullanmaktadrlar. Bu prosedür, obturasyon için kök kanallarnn hazrlanmasna yardmc olur. Dahas, bir sürfaktan ilavesi ile EDTA solüsyonlar bir kök kanal içindeki kireçlenmeyi gevetir ve enstrümantasyona (kanallar ekillendirmeye) imkan tanr ve apikse doru kkrdak kök kanalndaki bir dosyann apikal ilerlemesini kolaylatrr.
Göz preparatlarnda ve göz damlalarnda koruyucu olarak (genellikle benzalkonyum klorid veya tiyomersal gibi baka bir koruyucunun etkisini arttrmak için) görev yapar.
Böbrek fonksiyonunu deerlendirirken kompleks [Cr (edta)] – intravenöz olarak uygulanr ve filtrasyon idrarnda izlenir. Bu yöntem glomerüler filtrasyon hzn deerlendirmede kullanldr.
EDTA kan analizinde yaygn olarak kullanlr. CBC / FBE’ler için kan örnekleri için antikoagülantr.
EDTA, bir sümük datcdr ve intraoküler lenslerin (GL) implantasyonu srasnda bakteri geliimini azaltmada oldukça etkili olduu bulunmutur.
EDTA 2Na
‘EDTA 2Na est un acide aminopolycarboxylique et un solide incolore et soluble dans l’eau.La base conjuguée d’EDTA 2Nas est l’éthylènediaminetétraacétate. L’EDTA 2Na est largement utilisé pour dissoudre le calcaire. L’utilité de l’EDTA 2Na résulte de son rôle de ligand hexadenté (“à six dents”) et d’agent chélatant, c’est-à-dire sa capacité à séquestrer des ions métalliques tels que Ca2 + et Fe3 +. Après avoir été liés par EDTA 2Na dans un complexe métallique, les ions métalliques restent en solution mais présentent une réactivité diminuée. L’EDTA 2Na est produit sous forme de plusieurs sels, notamment l’EDTA disodique 2Na, l’EDTA calcique disodique 2Na et l’EDTA tétrasodique (généralement sous forme d’hydrate).
Les usages
Industrie
Dans l’industrie, l’EDTA 2Na est principalement utilisé pour séquestrer les ions métalliques en solution aqueuse. Dans l’industrie textile, il empêche les impuretés des ions métalliques de modifier les couleurs des produits teints. Dans l’industrie des pâtes et papiers, l’EDTA 2Na inhibe la capacité des ions métalliques, en particulier Mn2 +, de catalyser la disproportionation du peroxyde d’hydrogène, qui est utilisé dans le blanchiment sans chlore. De manière similaire, l’EDTA 2Na est ajouté à certains aliments comme conservateur ou stabilisant pour empêcher la décoloration oxydative catalytique, qui est catalysée par des ions métalliques. [5] Dans les boissons gazeuses contenant de l’acide ascorbique et du benzoate de sodium, l’EDTA 2Na atténue la formation de benzène (un cancérogène). [6]
La réduction de la dureté de l’eau dans les applications de blanchisserie et la dissolution du tartre dans les chaudières reposent toutes deux sur l’EDTA 2Na et les complexants apparentés pour lier Ca2 +, Mg2 +, ainsi que d’autres ions métalliques. Une fois liés à l’EDTA 2Na, ces centres métalliques ont tendance à ne pas former de précipités ou à interférer avec l’action des savons et détergents. Pour des raisons similaires, les solutions de nettoyage contiennent souvent de l’EDTA 2Na. De la même manière, l’EDTA 2Na est utilisé dans l’industrie du ciment pour la détermination de la chaux libre et de la magnésie libre dans le ciment et les clinkers. [7] [page nécessaire]
La solubilisation des ions Fe3 + à ou en dessous d’un pH presque neutre peut être accomplie en utilisant de l’EDTA 2Na. Cette propriété est utile dans l’agriculture, y compris la culture hydroponique. Cependant, étant donné la dépendance au pH de la formation de ligands, l’EDTA 2Na n’est pas utile pour améliorer la solubilité du fer dans des sols plus neutres. [8] Sinon, à un pH presque neutre et au-dessus, le fer (III) forme des sels insolubles, qui sont moins biodisponibles pour les espèces végétales sensibles. [Fe (EDTA 2Na)] aqueux – est utilisé pour éliminer («épurer») le sulfure d’hydrogène des courants gazeux. Cette conversion est obtenue en oxydant le sulfure d’hydrogène en soufre élémentaire, non volatil:
2 [Fe (EDTA)] – + H2S → 2 [Fe (EDTA)] 2- + S + 2 H +
Dans cette application, le centre du fer (III) est réduit en son dérivé du fer (II), qui peut ensuite être réoxydé par l’air. De la même manière, les oxydes d’azote sont éliminés des courants gazeux à l’aide de [Fe (edta)] 2-. Les propriétés oxydantes de [Fe (edta)] – sont également exploitées en photographie, où il est utilisé pour solubiliser les particules d’argent. [9]
L’EDTA 2Na a été utilisé pour la séparation des métaux lanthanides par chromatographie d’échange d’ions. Perfectionné par F. H. Spedding et al. en 1954, [la citation nécessaire] la méthode repose sur l’augmentation constante de la constante de stabilité des complexes de lanthanides EDTA 2Na avec le numéro atomique. En utilisant des billes de polystyrène sulfoné et du Cu2 + comme ion de rétention, l’EDTA 2Na fait migrer les lanthanides dans la colonne de résine tout en se séparant en bandes de lanthanides purs. Les lanthanides éluent par ordre décroissant de nombre atomique. En raison du coût de cette méthode, par rapport à l’extraction au solvant à contre-courant, l’échange d’ions n’est désormais utilisé que pour obtenir les plus grandes puretés de lanthanides (généralement supérieures à 99,99%).
Biodégradation
Dans de nombreuses usines de traitement des eaux usées industrielles, l’élimination de l’EDTA 2Na peut être obtenue à environ 80% en utilisant des micro-organismes. [34] Les sous-produits résultants sont l’ED3A et l’acide iminodiacétique (IDA) – suggérant que les groupes de squelette et d’acétyle ont été attaqués. Certains microorganismes ont même été découverts pour former des nitrates à partir d’EDTA 2Na, mais ils fonctionnent de manière optimale dans des conditions modérément alcalines de pH 9,0-9,5. [35]
Plusieurs souches bactériennes isolées de stations d’épuration dégradent efficacement l’EDTA 2Na. Des souches spécifiques comprennent Agrobacterium radiobacter ATCC 55002 [36] et les sous-branches de protéobactéries comme BNC1, BNC2, [37] et la souche DSM 9103. [38] Les trois souches partagent des propriétés similaires de la respiration aérobie et sont classées comme bactéries gram-négatives. Contrairement à la photolyse, l’espèce chélatée n’est pas exclusive au fer (III) pour être dégradée. Au contraire, chaque souche consomme de manière unique divers complexes métal – EDTA 2Na par le biais de plusieurs voies enzymatiques. Agrobacterium radiobacter ne dégrade que Fe (III) EDTA 2Na [37] tandis que BNC1 et DSM 9103 ne sont pas capables de dégrader le fer (III) EDTA 2Na et conviennent mieux aux complexes de calcium, baryum, magnésium et manganèse (II). [39] Les complexes EDTA 2Na nécessitent une dissociation avant la dégradation.
Alternatives à EDTA 2Na
L’intérêt pour la sécurité environnementale a soulevé des inquiétudes quant à la biodégradabilité des aminopolycarboxylates tels que l’EDTA 2Na. Ces préoccupations incitent à rechercher des aminopolycarboxylates alternatifs. [31] Les agents chélatants candidats comprennent l’acide nitrilotriacétique (NTA), l’acide iminodisuccinique (IDS), l’acide polyaspartique, la S, S-éthylènediamine-N, l’acide N-disuccinique (EDDS), l’acide méthylglycinediacétique (MGDA) et l’acide L-glutamique N, N -acide diacétique, sel tétrasodique (GLDA). [40]