Kev piav qhia
Cov molecules ntawm cov khoom sib txawv yog qhov txawv ntawm qhov tseem ceeb thiab qhov loj ntawm adsorption, yog li cov duab hu ua "molecular sieve".
Molecular sieve (tseem hu ua hluavtaws zeolite) yog silicate microporous siv lead ua.Nws yog ib qho yooj yim skeleton qauv tsim ntawm silicon aluminate, nrog cov hlau cations (xws li Na +, K +, Ca2 +, thiab lwm yam) kom sib npaug cov nqi tsis zoo nyob rau hauv cov siv lead ua.Hom molecular sieve feem ntau muab faib ua hom A, X thiab Y hom raws li nws cov qauv siv lead ua.
| Tshuaj formula ntawm zeolite cell: | Mx/n [(AlO.2) x (SiO.2) y]WH.2O. |
| Mx/n:. | Cation ion, ua kom cov siv lead ua hluav taws xob nruab nrab |
| (AlO2) x (SiO2) y: | Lub cev pob txha ntawm zeolite muaju, nrog cov duab sib txawv ntawm qhov thiab cov kab |
| H2O: | lub cev adsorbed dej vapor |
| Nta: | Ntau yam adsorption thiab desorption tuaj yeem ua tau |
| Hom A Molecular Sieve | Lub ntsiab tivthaiv ntawm hom A molecular sieve yog silicon aluminate. Lub ntsiab siv lead ua qhov yog octaring qauv.Qhov aperture ntawm lub ntsiab siv lead ua aperture yog 4Å(1Å=10-10m), hu ua hom 4A (tseem hu ua hom A) molecular sieve;
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| Hom X Molecular Sieve | Lub ntsiab ntawm X molecular sieve yog silicon aluminate, lub ntsiab siv lead ua qhov yog kaum ob lub nplhaib qauv. Ca2 + pauv rau Na + nyob rau hauv 13X molecular sieve, tsim lub molecular sieve siv lead ua nrog aperture ntawm 8-9 A, hu ua 10X (tseem hu ua calcium X) molecular sieve.
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Hom A Molecular Sieve
Hom X Molecular Sieve
Daim ntawv thov
Lub adsorption ntawm cov khoom yog los ntawm lub cev adsorption (vander Waals Force), muaj zog polarity thiab Coulomb teb nyob rau hauv nws cov siv lead ua qhov, qhia muaj zog adsorption muaj peev xwm rau polar molecules (xws li dej) thiab unsaturated molecules.
Lub aperture faib ntawm molecular sieve yog heev sib xws, thiab tsuas yog cov khoom uas muaj ib tug molecular txoj kab uas hla me tshaj lub qhov taub yuav nkag mus rau hauv lub crystal qhov nyob rau hauv lub molecular sieve.