1. Basic Physical & Chemical Properties
EDTA (Ethylenediaminetetraacetic acid) yog ib tug hexadentate chelating tus neeg sawv cev uas tsim 1: 1 ruaj khov complexes nrog feem ntau hlau ions. Peb hom EDTA ntsev sib txawv heev hauv cov ntsiab lus sodium thiab ua ntej- calcium complexed, ua rau cov tshuaj pH txawv, solubility thiab chelating kev ua tau zoo.
| Yam khoom | EDTA Disodium | EDTA Tetrasodium tshuaj | EDTA Calcium Disodium |
|---|---|---|---|
| Tshuaj Formula | Na2H2C10H12N2O8 | Na4C10H12N2O8 | CaNa2C10H12N2O8 |
| pH ntawm 1% Aqueous Solution | 4.5-6.0 (tsis muaj acidic) | 10.0-11.0 (Alkaline muaj zog heev) | 7.0–8.0 (ze nruab nrab) |
| Solubility (25 degree) | Nruab nrab (~ 100 g / L) | Zoo heev (~ 250 g / L) | Nruab nrab (~ 100 g / L) |
| Molecular Luj | 372.24 (Dihydrate) | 380.17 | 374.27 |
2. Qhov zoo tshaj pH ntau & Chelating Performance
EDTA lub chelate efficiency yog pH heev - nyob ntawm. Ntau tag nrho deprotonated \\(\\boldsymbol{Y^{4-}}\\) ions muaj nyob ntawm pH siab dua, uas ua rau muaj zog chelating muaj peev xwm.
2.1 EDTA Disodium
Qhov zoo tshaj pH ntau yam4.0-7.0 (Tsis muaj kua qaub rau nruab nrab)
Daim ntawv tseem ceeb uas twb muaj lawm hauv kev daws: \\(\\boldsymbol{H_2Y^{2-}}\\). Nws maj mam hloov mus rau \\(\\boldsymbol{HY^{3-}}\\) thiab \\(\\boldsymbol{Y^{4-}}\\) thaum pH tshaj 6.2.
Kev ua tau zoo: Kev ua haujlwm siab tshaj chelate rau \\(\\boldsymbol{Ca^{2+}}, Mg^{2+}, Fe^2+}, Cu^{2+}}\\) ntawm pH 5–7. Kev ua tau zoo poob qis qis dua pH 4.
Cov ntawv thov raug: khaws cia zaub mov, tshuaj, tshuaj pleev ib ce, kho dej thiab kuaj titration.
2.2 EDTA Tetrasodium 2
Qhov zoo tshaj pH ntau yam8.0-11.0 (Tsis muaj zog alkali)
Daim ntawv tseem ceeb uas twb muaj lawm hauv kev daws: Siab deprotonated \\(\\boldsymbol{Y^{4-}}\\) tom qab dissolution.
Kev ua tau zoo: Lub zog chelating zoo rau siab -valent hlau zoo li \\(\\boldsymbol{Fe^{3+}}, Al^{3+}}\\) nyob rau hauv alkaline tej yam kev mob. Kev ua haujlwm tsis zoo hauv qab pH 7 vim yog protonation.
Cov ntawv thov: Muaj cov tshuaj ntxuav tes, textile & paper bleaching, oilfield water treatment and alkaline cleaning formulations.
2.3 EDTA Calcium Disodium
Qhov zoo tshaj pH ntau yam6.0-9.0 (Neutral rau qaug zog alkali)
Yam ntxwv: Ua ntej- nyuaj nrog calcium ions. Calcium tuaj yeem hloov tau los ntawm cov hlau hnyav xws li txhuas thiab mercury.
Kev ua tau zoo: Xaiv khi cov hlau hnyav hnyavtsis muaj chelate calcium thiab magnesium, uas tsis txhob muaj calcium deficiency txaus ntshai.
Cov ntawv thov raug: Kev pab thawj zaug rau cov hlau lead / hnyav hlau lom thiab kev kho mob chelation kho.
3. Kev sib piv ntawm Chelating Capacity
Qhov hnyav-raws li tus nqi chelate (mg CaCO₃/g):
EDTA Disodium: Ntau dua lossis sib npaug ntawm 265 mg / g (siab tshaj)
EDTA Tetrasodium: Ntau dua lossis sib npaug li 220 mg / g
EDTA Calcium Disodium: ≈ 180 mg/g (qis tshaj plaws, nyob hauv chelating qhov chaw los ntawm ua ntej- khi calcium)
Molar ratio: Tag nrho peb cov khoom ua ke nrog cov hlau ions ntawm a1: 1 molar ratio.
4. Cov txheej txheem xaiv
Ua ke nrog pH system
Lub cev tsis muaj zog acidic & nruab nrab (pH 4–7): Xaiv EDTA Disodium (qib thoob ntiaj teb)
Alkaline systems (pH 8-11): Xaiv EDTA Tetrasodium (siab solubility & muaj zog alkalinity resistance)
Kev kho mob & kab mob lom: Xaiv EDTA Calcium Disodium (muaj kev nyab xeeb rau calcium tshuav)
Chelating peev xwm qeb duas (los ntawm qhov hnyav sib npaug)EDTA Disodium > EDTA Tetrasodium > EDTA Calcium Disodium
Solubility xav txog
Siab -kev sib xyaw ua ke & ceev- cov qauv yaj: Nyiam EDTA Tetrasodium
Cov tshuaj tsis tu ncua: Nyiam EDTA Disodium
5. Kev xav tsis zoo
Lus dab neeg: EDTA Tetrasodium muaj qhov muaj peev xwm chelating muaj zog tshaj plaws.Qhov tseeb: EDTA Disodium muaj tus nqi chelating ntau dua ib chav tsev qhov hnyav. Tetrasodium excels tsuas yog nyob rau hauv alkaline ib puag ncig thiab solubility siab.
Lus dab neeg: EDTA Calcium Disodium tsis tuaj yeem chelate hlau.Qhov tseeb: Nws ua haujlwm tau zoo thiab khi cov hlau hnyav xws li txhuas thiab mercury, thaum tawm hauv calcium thiab magnesium untouched.
6. Cov ntsiab lus
EDTA Disodium: pH 4-7, siab tshaj chelate muaj peev xwm, universal chelator rau acid & nruab nrab formulations.
EDTA Tetrasodium tshuaj: pH 8-11, superior solubility, tshwj xeeb tshaj yog tsim rau alkaline industrial systems.
EDTA Calcium Disodium: pH 6–9, xaiv chelation rau cov hlau hnyav, tshwj xeeb rau kev kho mob.