Qhov sib txawv ntawm cov ntawv lim thiab cov ntawv ib txwm muaj
Txawv ntawmzoo tib yam lim ntawv, feem ntau daim ntawv yog ua los ntawm paj rwb fibers thiab yog ua nyob rau hauv ntau txoj kev rau txawv hom phiaj. Vim tias nws yog ua los ntawm fiber ntau, qhov saum npoo muaj ntau qhov los ntawm cov khoom ua kua tuaj yeem dhau mus, thaum cov khoom loj dua tsis tuaj yeem, yog li cov ntawv lim dej muaj cov haujlwm ntawm lub lim. Cov cuab yeej no tso cai rau kev sib xyaw ua kua thiab cov khoom sib cais. Cov duab zoo ib yam yog lim ntawv disc thiab lim ntawv yob, feem ntau yog ua los ntawm paj rwb fiber ntau.
Ordinary filter paper vs ashless paper. Cov ntawv lim dej tsuas tuaj yeem nqus tau 23% ntawm cov dej, thiab tsis tuaj yeem ua tiav cov nyhuv lim dej. Daim ntawv, ntawm qhov tod tes, yog ib daim ntawv nyias ua los ntawm cov nroj tsuag fibers. Ntxiv rau qhov ua tau zoo ntawm cov ntawv lim dej, cov ntawv lim tsis muaj hmoov tshauv yog purer thiab muaj cov hmoov tshauv qis dua (tsawg dua 0.01%). Tus nqi pH ntawm cov dej rho tawm yog nyob nruab nrab ntawm 5.0 thiab 8.0. Nws muaj lub zog ntub dej zoo thiab ua haujlwm rau dilute acid.
Cov ntawv lim dej yog qhov nruab nrab lim dej zoo, lim ntawv tau siv dav hauv ntau qhov chaw. Raws li muaj pes tsawg leeg ntawm ntau hom lim ntawv fiber ntau, lim ntawv kev ua tau zoo, thiab kev siv tsis zoo ib yam, muaj lub sijhawm zoo tib yam rau cov ntawv lim dej zoo tib yam, thiab rau cov iav fiber ntau qhov kub thiab txias, muaj ultra-ntshiab polypropylene lim. ntawv. Paint filter paper tseem hu ua v-type dry filter paper, organ-type spray cabinet filter, and paint mist filter paper (folding filter board). Nws yog siv nyob rau hauv cov tshuaj tsuag qhuav qhuav ntawm cov khoom tiv thaiv ib puag ncig tshiab, nws siv ib puag ncig tiv thaiv lim ntawv. Nws ua rau cov tshuaj tsuag roj / xim tsis muaj dej ntxiv, tsis muaj kuab paug ntxiv! Ua tau zoo lim xim, roj, iav raw khoom, epoxy resin, asphalt, hlau zaj, liquefied workpiece, yas, porcelain, dye, thiab txheej txheej
Qhov sib txawv ntawm cov ntawv lim thiab cov ntawv ib txwm tuaj yeem sau tau raws li hauv qab no
Porosity: Cov ntawv lim muaj qhov porosity tshwj xeeb uas tso cai rau nws lim tawm qee yam, thaum daim ntawv ib txwm tsis muaj cov khoom no.
Pore loj: Lub pore loj ntawm cov ntawv lim tau ua tib zoo tswj, thaum daim ntawv ib txwm muaj qhov sib faib ntawm qhov pores.
Thickness: Cov ntawv lim feem ntau yog nyias thiab muag ntau dua li cov ntawv ib txwm, kom tso cai rau kev pom zoo.
Kev tiv thaiv rau cov tshuaj: Cov ntawv lim feem ntau raug kho nrog cov tshuaj ua kom nws tiv taus ntau yam tshuaj lossis cov kuab tshuaj, thaum daim ntawv ib txwm tsis yog.
Daim ntawv lim dej yog dab tsi?
Filter paper filtration yog qhov ua haujlwm ntawm chromatography. Daim ntawv chromatography yog raws li cov ntawv lim raws li kev txhawb nqa. Cov ntawv lim fiber ntau thiab dej muaj qhov sib txuam zoo, thiab tuaj yeem nqus tau li ntawm 22 feem pua ntawm cov dej, thiab 6 mus rau 7 feem pua ntawm nws yog hydrogen-bonded rau hydroxide pawg ntawm cellulose, uas nyuaj rau tshem tawm nyob rau hauv ib txwm muaj mob.
Cov ntawv lim fiber ntau thiab cov organic hnyav affinity tsis muaj zog heev, yog li cov ntawv dav dav chromatography, qhov tseeb, nrog cov dej sib xyaw ntawm cov ntawv lim fiber ntau raws li cov theem nyob ruaj khov, nrog cov organic hnyav raws li theem mobile, thaum ntws hauv daim ntawv tom qab qauv, piv txwv point ntawm cov kuab tshuaj nyob rau hauv dej thiab organic theem nyob rau hauv lub nruam tis, ib feem ntawm cov qauv nrog rau lub mobile theem, mus rau hauv lub cheeb tsam ntawm lub solute, lub sij hawm no thiab redistribution, ib feem ntawm lub solute los ntawm lub mobile theem mus rau theem nyob ruaj khov (dej) . Nrog rau kev txav mus tas li ntawm lub sijhawm txawb, qhov sib txawv tau muab faib ua ntu zus raws li lawv cov kev faib coefficients thiab txav mus rau theem mobile, kom cov khoom sib cais thiab huv si.
Vim li cas cov ntawv lim siv hauv chromatography?
Nyob rau hauv daim ntawv chromatography, lim ntawv tsuas yog ib qho kev txhawb nqa rau cov kua nyob ruaj ruaj. Nws tuaj yeem pom los ntawm lub hauv paus ntsiab lus tias qhov sib faib coefficient ntawm cov kuab tshuaj nyob rau hauv cov qauv yog txawv ntawm cov theem nyob ruaj khov thiab theem mobile. Cov theem ntawm lub xov tooj ntawm tes (xws li dej) nce vim qhov kev txiav txim ntawm capillary, thiab cov dej ntws ruaj khov yog qeeb dua li theem ntawm lub xov tooj ntawm tes, yog li cov kua dej sib cais. Cov ntawv fibers thiab dej muaj qhov sib txuam ntau dua thiab tuaj yeem nqus tau 20% -25% ntawm cov dej, ntawm 6% ntawm cov dej yog ua ke nrog cov ntawv fibers hauv daim ntawv ntawm hydrogen bonds los ua ib qho kev sib xyaw.
Lub hom phiaj ntawm cov ntawv lim hauv TLC yog dab tsi?
Lub hom phiaj ntawm cov ntawv lim hauv TLC yog siv los ntsuas qhov muaj ntau yam ntaub ntawv, saib xyuas tus nqi thiab txheej txheem ntawm cov tshuaj tiv thaiv, lossis txiav txim siab qhov purity ntawm cov khoom.
Vim li cas thiaj siv lim ntawv?
Cov ntawv lim rau kev siv hauv chav kuaj yog ib qho cuab yeej siv nrog cov kws tshawb fawb. Cov ntawv lim tuaj yeem muab faib ua ob yam zoo thiab ntau yam. Nyob rau hauv daim ntawv thov ntawm analytical chemistry, tom qab cov inorganic compound precipitate yog sib cais los ntawm filtration, cov residue yog sau rau ntawm daim ntawv lim, thiab tus nqi poob nyob rau hauv qhov kev sim yuav xam tau. Cov ntaub ntawv lim dej zoo tom qab pom ntau cov paj rwb fiber ntau, yog li tsuas yog tsim nyog rau kev soj ntsuam zoo; cov ntaub ntawv lim dej ntau, tshwj xeeb tshaj yog cov ntawv lim dej tsis muaj hmoov tshauv, tuaj yeem tiv thaiv cov tshuaj tiv thaiv zoo dua tom qab cov txheej txheem tshwj xeeb, yog li cov impurities generated tsawg dua, uas tuaj yeem siv rau kev soj ntsuam ntau.
Ntxiv nrog rau kev siv tshuaj lom neeg kev sim, tseem muaj kev siv cov ntawv lim dej ntau zaus hauv lub neej txhua hnub thiab engineering. Kas fes lim ntawv yog ib qho ntawm cov khoom siv dav siv hauv lub neej niaj hnub, thiab cov ntawv lim dej ntawm cov txheej txheem ntawm cov teabag muab siab softness thiab siab ntub dej. Lwm cov ntaub ntawv lim dej yog cov ntawv lim cua rau kev soj ntsuam cov khoom tshem tawm hauv huab cua, thiab cov ntawv lim fiber ntau rau cov ntawv thov kev lag luam.
Yuav ua li cas xaiv cov ntawv lim kom raug?
Thaum xaiv cov ntawv lim, cov ntsiab lus tseem ceeb yuav tsum yog:
1. Qhov siab dua cov ntsiab lus ntawm cov khoom siv lim dej, qhov siab dua tensile lub zog ntawm cov ntawv lim, qhov ua tau zoo dua thaum lub sij hawm pom, thiab qhov qis dua. Yog tias cov khoom siv lim dej tom qab plua plav me me, nws qhov kev tiv thaiv yog qhov zoo, tab sis qhov tsis kam yuav nce ntxiv.
2. Qhov me me ntawm fiber ntau txoj kab uas hla, qhov zoo dua qhov cuam tshuam cuam tshuam ntawm cov khoom sim, yog li qhov pom kev ua haujlwm zoo dua qub.
3. Qhov chaw ua haujlwm tau zoo yog qhov loj, uas yog, lub lim ntawv siv cheeb tsam loj, tuaj yeem ua raws li cov plua plav ntim loj, nws qhov kev tiv thaiv me me, nws lub neej kev pabcuam ntev, tus nqi kuj tseem nce ntxiv.
