Qhov sib txawv tseem ceeb ntawm molecular sieve thiab silica gel yog tias molecular sieve yog cov khoom uas muaj qhov hws ntawm qhov loj me, qhov silica gel yog ib yam khoom siv los npaj cov khoom ntxeem tau nrog qhov pores ntawm ntau qhov sib txawv.
Ob qho tib si molecular sieve thiab silica gel yog cov ntaub ntawv tseem ceeb hauv kev sib cais tshuaj. Lawv yog cov ntaub ntawv ntxeem tau uas muaj qhov pores uas tso cai rau qee qhov kev txheeb xyuas dhau los thaum khaws lwm tus. Los ntawm kev xaiv qhov pore loj, peb tuaj yeem cais qhov sib xyaw ntawm kev ntshaw los ntawm kev sib tov.
Molecular Sieve yog dab tsi?
Molecular sieve yog cov khoom siv nrog qhov me me (pores) nrog qhov loj me. Qhov no txhais tau hais tias pores muaj cov kab uas zoo sib xws. Yog li ntawd, peb tuaj yeem siv molecular sieves rau kev sib cais ntawm cov khoom me me los ntawm cov khoom loj. Thaum sib tov ntawm qhov sib txawv me me dhau los ntawm ib qho molecule sieve, cov khoom loj tawm ntawm lub sieve ua ntej ua raws li cov khoom nruab nrab. Muaj ob qhov kev siv loj ntawm molecular sieves: siv hauv chromatography raws li kev sib cais thiab siv los ua desiccants, piv txwv li. activated charcoal.
Feem ntau, qhov loj ntawm qhov pores ntawm molecular sieve yog li ntawm nanometer scale mus rau angstrom scale. Muaj ob hom molecular sieves raws li qhov loj ntawm qhov pores: microporous sieves thiab macroporous sieves. Qhov loj ntawm qhov pores hauv microporous sieves feem ntau tsawg dua 2 nm. Macroporous sieves muaj qhov pores feem ntau siab dua 50 nm. Kuj tseem muaj lwm pawg ntawm molecular sieves li mesoporous sieves, uas muaj qhov pore loj li ntawm 2 txog 50 nm.
Qee yam piv txwv ntawm microporous sieves muaj xws li zeolites, activated carbon, av nplaum, thiab porous iav. Ib qho piv txwv ntawm cov ntaub ntawv mesoporous yog silica gel. Ib qho piv txwv ntawm cov khoom siv macroporous yog mesoporous silica.
Daim duab 01: Mesoporous Silica
Qhov zoo dua ntawm molecular sieves yog tias peb tuaj yeem tsim cov ntaub ntawv no rau kev siv ntxiv. Muaj ob peb txoj hauv kev rau kev rov tsim dua tshiab no, suav nrog, hloov siab, cua sov, purging nrog cov pa roj carbon monoxide, thiab cua sov hauv qab lub tshuab nqus tsev siab.
Silica Gel yog dab tsi?
Silica gel yog hom molecular sieve uas muaj cov qauv tsis sib xws ntawm silicon thiab oxygen atoms nrog cov pores tsis sib xws. Cov khoom no yog amorphous daim ntawv ntawm silicon dioxide. Nws muaj nanometer-scale voids thiab pores. Cov voids no yuav muaj dej los yog lwm yam kua dej uas peb siv hauv kev npaj cov silica gel. E.g. roj, lub tshuab nqus tsev, lwm cov kuab tshuaj, thiab lwm yam. Vim tias qhov pore qhov ntau thiab tsawg yog qhov tsis sib xws, peb tuaj yeem hais tias qhov no molecular sieve muaj qhov nruab nrab qhov pore loj ntawm 2.4 nm.
Silica gel muaj kev sib raug zoo rau dej; Yog li, peb tuaj yeem siv nws ua tus desiccant. Cov khoom no yog ib qho nyuaj heev thiab translucent. Txawm li cas los xij, nws yog qhov muaj txiaj ntsig zoo dua li silica iav lossis quartz. Thaum silica gel saturated nrog dej, nws tseem nyob rau hauv ib qho nyuaj.
Daim duab 02: Silica Gel
Hauv qib kev lag luam, peb tuaj yeem pom silica gel hauv daim ntawv granules lossis hlaws. Cov hlaws no muaj txoj kab uas hla ntawm ob peb millimeters. Qee lub sij hawm, cov hlaws dai no kuj muaj qee qhov ntawm qhov ntsuas reagent uas tuaj yeem hloov xim ntawm cov hlaws thaum dej nqus. Raws li cov khoom siv desiccant, cov hlaws dai no suav nrog hauv cov pob khoom noj ua cov pob me me kom nqus dej vapor hauv pob.
Qhov txawv ntawm Molecular Sieve thiab Silica Gel yog dab tsi?
Qhov sib txawv tseem ceeb ntawm molecular sieve thiab silica gel yog tias molecular sieve yog cov khoom uas muaj qhov hws ntawm qhov loj me, qhov silica gel yog ib yam khoom uas peb tuaj yeem siv los npaj cov khoom ntxeem tau uas muaj qhov pores nrog ntau qhov sib txawv. Ntxiv mus, molecular sieves yog tsuas yog siv nyob rau hauv chromatography raws li ib tug sib cais txheej txheem, thiab raws li desiccants thaum silica gel yog tsuas yog siv raws li ib tug desiccant.
Hauv qab infographic qhia txog qhov sib txawv ntawm molecular sieve thiab silica gel.
Summary – Molecular Sieve vs Silica Gel
Molecular sieve thiab silica gel yog cov ntaub ntawv tseem ceeb hauv kev tshuaj xyuas tshuaj. Qhov sib txawv tseem ceeb ntawm molecular sieve thiab silica gel yog cov khoom siv molecular sieve yog cov khoom uas muaj cov pores ntawm qhov loj me me whereas silica gel yog ib yam khoom uas peb tuaj yeem siv los npaj cov khoom ntxeem tau uas muaj qhov pores nrog ntau qhov sib txawv.
