Dab tsi yog molecular sieves, thiab lawv cov nqi tseem ceeb yog dab tsi?
Molecular sieves yog cov khoom siv hluavtaws aluminosilicate uas muaj cov qauv microporous. Lawv qhov pore qhov ntau thiab tsawg yog piv rau molecular diameters, tso cai rau lawv ua zoo li "sieve" los ntawm kev xaiv adsorbing tshwj xeeb molecules. Piv txwv li, hauv huab cua sib cais, lawv tuaj yeem nqus tau nitrogen thaum tso pa oxygen mus rau hauv; Hauv kev kho dej khib nyiab, lawv tuaj yeem nqus cov hlau hnyav ions. Cov khoom no ua rau lawv "cov ntaub ntawv hnub qub" hauv thaj chaw xws li kev sib cais tshuaj, roj ziab, thiab kev txhawb nqa catalyst. Lub hom phiaj ntawm kev ua cov khoom siv molecular sieve yog los hloov cov ntaub ntawv raw rau hauv cov khoom ua tau zoo -.
Cov txheej txheem tseem ceeb: Peb - kauj ruam taug kev los ntawm cov khoom siv raw mus rau cov khoom tiav
Molecular sieve ntau lawm tsis yog ib qho teeb meem ntawm kev sib xyaw yooj yim; nws muaj cov txheej txheem chemically meej. Noj hom A molecular sieve ua piv txwv, kev ua haujlwm muaj peb kauj ruam:
Kauj Ruam 1: Raw khoom proportioning thiab sib tov. Cov ntaub ntawv tseem ceeb -xws li sodium silicate, aluminium hydroxide, sodium hydroxide, thiab dej- yog sib xyaw rau hauv ib qho piv txwv los ua ib qho slurry homogeneous. Qhov tseeb ntawm qhov kev faib ua feem ncaj qha txiav txim siab qhov pore loj thiab adsorption kev ua tau zoo ntawm qhov kawg molecular sieve.
Kauj Ruam 2: Crystallization thiab shaping. Lub slurry undergoes crystallization ntawm qhov kub thiab txias rau ob peb teev los tsim ib tug microporous crystalline qauv. Tom qab ntawd, cov khoom siv lead ua tau hloov mus rau hauv cov hmoov lossis cov khoom siv granular los ntawm cov tshuaj tsuag kom qhuav lossis extrusion. Piv txwv li, molecular sieves siv rau ziab daim ntaub ntawv yog feem ntau zoo li tus kheej kheej granules los ua kom muaj kev sib cuag cheeb tsam.
Kauj Ruam 3: Qhib thiab ntim khoom. Cov zoo li molecular sieves yuav tsum tau qhib rau ntawm qhov kub thiab txias kom tshem tawm cov dej noo thiab impurities ntawm lub qhov hws, yog li rov ua kom lawv lub peev xwm adsorption. Thaum kawg, cov khoom lag luam raug kuaj xyuas thiab kuaj xyuas kom ntseeg tau tias qhov loj me me ntawm kev faib tawm thiab adsorption kev ua tau zoo raws li cov qauv ua ntej yuav ntim thiab xa khoom.
