Sieve ya molekyulu ndi chinthu chokhala ndi pores (mabowo ang'onoang'ono kwambiri) a kukula kwake.Ma pore diameters awa ndi ofanana kukula kwa mamolekyu ang'onoang'ono, motero mamolekyu akulu sangathe kulowa kapena kutsatsa, pomwe mamolekyu ang'onoang'ono amatha.Pamene chisakanizo cha mamolekyu chimayenda pabedi losasunthika la porous, semi-solid substance yotchedwa sieve (kapena matrix), zigawo za molekyulu zolemera kwambiri (zomwe sizingadutse mu ma pores a molekyulu) zimasiya bedi poyamba, kutsatiridwa ndi mamolekyu ang’onoang’ono motsatizana.Masefa ena a molekyulu amagwiritsidwa ntchito popanga chromatography, njira yolekanitsa yomwe imasankha mamolekyu potengera kukula kwake.Ma sieve ena a molekyulu amagwiritsidwa ntchito ngati desiccants (zitsanzo zina zimaphatikizapo makala opangidwa ndi silika ndi silika).
Kutalika kwa pore kwa sieve ya molekyulu kumayesedwa mu ångströms (Å) kapena nanometers (nm).Malinga ndi zolemba za IUPAC, zida za microporous zili ndi ma pore diameters osachepera 2 nm (20 Å) ndipo zida zazikulu zimakhala ndi ma pore diameters oposa 50 nm (500 Å);gulu la mesoporous motero lili pakati ndi pore diameters pakati pa 2 ndi 50 nm (20–500 Å).
Zipangizo
Masieve a mamolekyu amatha kukhala a microporous, mesoporous, kapena macroporous material.
Microporous material (
● Zeolites (aluminosilicate mchere, osati kusokonezedwa ndi aluminiyamu silicate)
●Zeolite LTA: 3–4 Å
● Magalasi amadzi: 10 Å (1 nm), ndi mmwamba
● Mpweya wa carbon: 0–20 Å (0–2 nm), ndi mmwamba
●Dongo
● Montmorillonite intermixes
● Halloysite (endellite): Mitundu iwiri yodziwika bwino imapezeka, dongo likathiridwa madzi limasonyeza 1 nm kutalikirana kwa zigawozo ndipo pamene madzi atayika (meta-halloysite) malo ndi 0.7 nm.Halloysite mwachilengedwe imapezeka ngati masilinda ang'onoang'ono omwe amakhala pafupifupi 30 nm m'mimba mwake ndi kutalika pakati pa 0.5 ndi 10 ma micrometres.
Mesoporous zinthu (2–50 nm)
Silicon dioxide (yomwe imagwiritsidwa ntchito popanga silika gel): 24 Å (2.4 nm)
Macroporous (> 50 nm)
Macroporous silika, 200–1000 Å (20–100 nm)
Mapulogalamu[edit]
Ma molekyulu amasefa nthawi zambiri amagwiritsidwa ntchito m'makampani a petroleum, makamaka poumitsa mitsinje ya gasi.Mwachitsanzo, m'makampani opanga gasi wamadzimadzi (LNG), madzi omwe ali mu gasi amafunika kuchepetsedwa mpaka 1 ppmv kuti apewe kutsekeka komwe kumachitika chifukwa cha ayezi kapena methane clathrate.
Mu labotale, ma sieve a molekyulu amagwiritsidwa ntchito kupukuta zosungunulira."Sieves" atsimikizira kuti ndi apamwamba kuposa njira zowumitsa zachikhalidwe, zomwe nthawi zambiri zimagwiritsa ntchito ma desiccants aukali.
Pansi pa mawu akuti zeolites, ma sieve a molekyulu amagwiritsidwa ntchito pazinthu zingapo zothandizira.Amathandizira isomerization, alkylation, ndi epoxidation, ndipo amagwiritsidwa ntchito m'njira zazikulu zamafakitale, kuphatikiza hydrocracking ndi kusweka kwamadzimadzi.
Amagwiritsidwanso ntchito pakusefera kwa zida zopumira, mwachitsanzo zomwe zimagwiritsidwa ntchito ndi osambira ndi ozimitsa moto.Muzochita zoterezi, mpweya umaperekedwa ndi mpweya wa compressor ndipo umadutsa mu fyuluta ya cartridge yomwe, malingana ndi ntchito, imadzazidwa ndi sieve ya molecular ndi / kapena activated carbon, potsirizira pake imagwiritsidwa ntchito kulipira matanki a mpweya wopuma. ndi zinthu zotulutsa kompresa kuchokera ku mpweya wopumira.
Chivomerezo cha FDA.
US FDA idavomereza kuyambira pa Epulo 1, 2012, kuti aluminosilicate ya sodium igwirizane mwachindunji ndi zinthu zomwe zimatha kudyedwa pansi pa 21 CFR 182.2727. Chivomerezochi chisanachitike bungwe la European Union lidagwiritsa ntchito sieve za ma molekyulu okhala ndi mankhwala komanso kuyezetsa kodziyimira pawokha kunanena kuti masefa a maselo amakwaniritsa zofunikira zonse za boma koma makampani sanafune kupereka ndalama zoyesera zodula zomwe zimafunikira kuti boma livomereze.
Kubadwanso
Njira zopangiranso masefa a ma molekyulu ndi monga kusintha kwa kuthamanga (monga zotengera mpweya), kutenthetsa ndi kuyeretsa ndi mpweya wonyamulira (monga momwe umagwiritsidwa ntchito pochotsamo ethanol), kapena kutenthetsa pansi pa vacuum yayikulu.Kutentha kwa kusinthika kumachokera pa 175 °C (350 °F) kufika pa 315 °C (600 °F) kutengera mtundu wa sieve ya maselo.Mosiyana ndi izi, gelisi ya silica imatha kupangidwanso mwa kutenthetsa mu uvuni wamba mpaka 120 ° C (250 ° F) kwa maola awiri.Komabe, mitundu ina ya gelisi ya silika "imatha" ikakhala ndi madzi okwanira.Izi zimachitika chifukwa cha kusweka kwa ma silika ozungulira polumikizana ndi madzi.
| Chitsanzo | Pore diameter (Ångström) | Kuchulukana (g/ml) | Adsorbed madzi (% w/w) | Kugwiritsa ntchito | |
| 3 Å | 3 | 0.60–0.68 | 19-20 | 0.3–0.6 | Desiccationzakuwonongeka kwa mafutampweya ndi alkenes, kusankha adsorption wa H2O mugalasi lotsekedwa (IG)ndi polyurethane, kuyanika kwamafuta a ethanolkwa kuphatikiza ndi mafuta. |
| 4 Å | 4 | 0.60–0.65 | 20–21 | 0.3–0.6 | Adsorption wa madzi musodium aluminosilicatezomwe zavomerezedwa ndi FDA (onanipansipa) amagwiritsidwa ntchito ngati sieve ya mamolekyulu m'zotengera zamankhwala kuti zamkati ziume komanso ngatichakudya chowonjezerakukhalaE-nambalaE-554 (anti-caking wothandizira);Kukonda kwa malo amodzi kuchepa madzi m'thupi mu chatsekedwa madzi kapena mpweya kachitidwe, mwachitsanzo, mu ma CD mankhwala, zida zamagetsi ndi kuwonongeka mankhwala;Kutaya madzi mu makina osindikizira ndi mapulasitiki ndi kuyanika mitsinje ya hydrocarbon yodzaza.Mitundu ya Adsorbed imaphatikizapo SO2, CO2, H2S, C2H4, C2H6, ndi C3H6.Nthawi zambiri amatengedwa ngati wowumitsa wapadziko lonse lapansi muzowulutsa za polar ndi nonpolar;[12]kulekana kwagasi wachilengedwendialkenes, kulowetsedwa kwa madzi m'malo okhudzidwa ndi nitrogenpolyurethane |
| 5Å-DW | 5 | 0.45–0.50 | 21-22 | 0.3–0.6 | Degreasing ndi kutsanulira mfundo maganizo andege palafinindidizilo, ndi kulekana kwa alkenes |
| 5Å wokhala ndi okosijeni pang'ono | 5 | 0.4–0.8 | ≥23 | Zopangidwira mwapadera zachipatala kapena jenereta wa okosijeni wathanzi[kufotokoza kofunikira] | |
| 5 Å | 5 | 0.60–0.65 | 20–21 | 0.3–0.5 | Desiccation ndi kuyeretsa mpweya;kuchepa madzi m'thupindidesulfurizationwa gasi ndigasi wamafuta amafuta;mpweyandihaidrojenikupanga ndikuthamanga kuthamanga adsorptionndondomeko |
| 10x pa | 8 | 0.50–0.60 | 23–24 | 0.3–0.6 | Kutsekemera kothandiza kwambiri, komwe kumagwiritsidwa ntchito mu desiccation, decarburization, desulfurization ya gasi ndi zakumwa ndi kulekanitsaonunkhira hydrocarbon |
| 13x pa | 10 | 0.55–0.65 | 23–24 | 0.3–0.5 | Desiccation, desulfurization ndi kuyeretsa gasi wamafuta ndi gasi |
| 13X-AS | 10 | 0.55–0.65 | 23–24 | 0.3–0.5 | Decarburizationndi desiccation mu makampani olekanitsa mpweya, kulekanitsa nayitrogeni kuchokera ku okosijeni mu zotengera mpweya |
| ku-13X | 10 | 0.50–0.60 | 23–24 | 0.3–0.5 | Kutsekemera(kuchotsedwa kwathiols) chamafuta oyendetsa ndegendi zogwirizanamadzi a hydrocarbon |
Maluso a Adsorption
3 Å
Chilinganizo cha mankhwala: ((K2O)2⁄3 (Na2O)1⁄3) • Al2O3• 2 SiO2 • 9/2 H2O
Chiŵerengero cha silika-aluminium: SiO2/ Al2O3≈2
Kupanga
3 Sieve ya molekyulu imapangidwa ndi kusinthana kwa cationpotaziyamuzasodiummu 4A masieve a molekyulu (Onani pansipa)
Kugwiritsa ntchito
3Å masikelo a molekyulu samatsatsa mamolekyu omwe ma diameter awo ndi akulu kuposa 3 Å.Makhalidwe a masieve a mamolekyuwa amaphatikizira kuthamanga kwachangu kwa adsorption, kuthekera kosinthika pafupipafupi, kukana kuphwanya bwino komansokukana kuipitsa.Zinthuzi zimatha kusintha magwiridwe antchito komanso moyo wonse wa sieve.3Å sieve ma molekyulu ndi zofunika desiccant m'mafakitale mafuta ndi mankhwala kuyenga mafuta, polymerization, ndi mankhwala gasi-zamadzimadzi kuyanika kuya.
3Å masefa a molekyulu amagwiritsidwa ntchito poumitsa zinthu zosiyanasiyana, mongaethanol, mpweya,mafiriji,gasi wachilengedwendiunsaturated hydrocarbons.Zomalizazi zikuphatikizapo kuphulika kwa gasi,acetylene,ethylene,propylenendibutadiene.
3Å sieve ya molekyulu imagwiritsidwa ntchito pochotsa madzi mu ethanol, yomwe pambuyo pake imatha kugwiritsidwa ntchito mwachindunji ngati biofuel kapena mwanjira ina kupanga zinthu zosiyanasiyana monga mankhwala, zakudya, mankhwala, ndi zina.Popeza kuti distillation wamba sangachotse madzi onse (osafunika kuchokera ku kupanga kwa ethanol) kuchokera mumitsinje ya ethanol chifukwa cha mapangidweazeotropepafupifupi 95.6 peresenti ndende ndi kulemera, maselo sieve mikanda ntchito kulekanitsa Mowa ndi madzi pa mlingo wa maselo ndi adsorbing madzi mu mikanda ndi kulola Mowa kudutsa momasuka.Mikanda ikadzadza ndi madzi, kutentha kapena kuthamanga kungathe kusinthidwa, kulola kuti madzi atuluke mumikanda ya molecular sieve.[15]
3Å sieves maselo amasungidwa firiji, ndi chinyezi wachibale osapitirira 90%.Amasindikizidwa pansi pa kupanikizika kochepa, kusungidwa kutali ndi madzi, zidulo ndi alkalis.
4 Å
Njira yamankhwala: Na2O•Al2O3•2SiO2•9/2H2O
Chiŵerengero cha silicon-aluminium: 1: 1 (SiO2/ Al2O3≈2)
Kupanga
Kupanga 4Å sieve ndikosavuta chifukwa sikufuna kupanikizika kwambiri kapena kutentha kwambiri.Childs amadzimadzi njira zasodium silicatendisodium aluminatezimaphatikizidwa pa 80 ° C.Chosungunulira chopangidwa ndi zosungunulira "chimatsegulidwa" ndi "kuphika" pa 400 °C 4A sieve imakhala ngati kalambulabwalo wa 3A ndi 5A sieves.kusinthana kwa cationzasodiumzapotaziyamu(kwa 3A) kapenacalcium(kwa 5A)
Kugwiritsa ntchito
Kuyanika zosungunulira
4Å masefa a molekyulu amagwiritsidwa ntchito kwambiri kuumitsa zosungunulira mu labotale.Amatha kuyamwa madzi ndi mamolekyu ena okhala ndi mainchesi ovuta kwambiri osakwana 4 Å monga NH3, H2S, SO2, CO2, C2H5OH, C2H6, ndi C2H4.Amagwiritsidwa ntchito kwambiri poyanika, kuyenga ndi kuyeretsa zakumwa ndi mpweya (monga kukonzekera argon).
Zowonjezera za polyester[sinthani]
Masefa a molekyuluwa amagwiritsidwa ntchito pothandizira zotsukira chifukwa zimatha kutulutsa madzi opanda mcherecalciumkusinthana kwa ion, chotsani ndikuletsa kuyika kwa dothi.Amagwiritsidwa ntchito kwambiri m'malophosphorous.Sieve ya 4Å molecular sieve imagwira ntchito yayikulu m'malo mwa sodium tripolyphosphate ngati chotsukira chothandizira kuti muchepetse kuwononga chilengedwe kwa chotsukira.Itha kugwiritsidwanso ntchito ngati asopokupanga agent ndi inmankhwala otsukira mano.
Kuchiza zinyalala zovulaza
4Å sieves maselo amatha kuyeretsa zimbudzi za mitundu cationic mongaammoniumions, Pb2+, Cu2+, Zn2+ ndi Cd2+.Chifukwa cha kusankha kwakukulu kwa NH4 + iwo agwiritsidwa ntchito bwino m'munda kuti amenyaneeutrophicationndi zotsatira zina m'madzi chifukwa cha ma ion ammonium.4Å masefa a molekyulu amagwiritsidwanso ntchito kuchotsa ayoni olemera omwe amapezeka m'madzi chifukwa cha ntchito zamafakitale.
Zolinga zina
Themakampani metallurgical: kulekanitsa wothandizira, kulekana, kuchotsa brine potaziyamu,rubidium,cesium, ndi zina.
Makampani a Petrochemical,chothandizira,desiccant, adsorbent
Agriculture:nthaka conditioner
Mankhwala: katundu silivazeoliteantibacterial wothandizira.
5 Å
Njira yamankhwala: 0.7CaO•0.30Na2O•Al2O3•2.0SiO2 •4.5H2O
Chiŵerengero cha silika-aluminium: SiO2/ Al2O3≈2
Kupanga
5 Sieve ya molekyulu imapangidwa ndi kusinthanitsa kwa cationcalciumzasodiummu 4A masikelo a molekyulu (Onani pamwambapa)
Kugwiritsa ntchito
Asanu-ångström(5Å) ma sieve a molekyulu amagwiritsidwa ntchito nthawi zambirimafutamafakitale, makamaka pakuyeretsa mitsinje ya gasi komanso mu labotale ya chemistry kuti alekanitsemankhwalandi kuyanika anachita poyambira zipangizo.Amakhala ndi tinthu ting'onoting'ono tating'onoting'ono komanso kukula kwake, ndipo amagwiritsidwa ntchito makamaka ngati adsorbent ya mpweya ndi zakumwa.
Sieve zisanu-ångström molekyulu zimagwiritsidwa ntchito kuti ziumegasi wachilengedwe, pamodzi ndi kuchitadesulfurizationndidecarbonationwa gasi.Atha kugwiritsidwanso ntchito kulekanitsa zosakaniza za okosijeni, nayitrogeni ndi haidrojeni, ndi mafuta-wax n-hydrocarbons kuchokera ku nthambi ndi ma polycyclic hydrocarbons.
Zisanu-ångström maselo sieves amasungidwa firiji, ndichinyezi chachibalezosakwana 90% m'migolo ya makatoni kapena katoni.Ma sieve a maselo sayenera kuwululidwa mwachindunji ndi mpweya ndi madzi, zidulo ndi alkali ziyenera kupewedwa.
Morphology ya sieve ya maselo
Masieve a mamolekyu amapezeka m'mawonekedwe ndi makulidwe osiyanasiyana.Koma mikanda yozungulira ili ndi mwayi kuposa mawonekedwe ena chifukwa imathandizira kutsika kwapang'onopang'ono, imalimbana ndi kutsika chifukwa ilibe m'mbali zakuthwa, ndipo imakhala ndi mphamvu zabwino, mwachitsanzo, mphamvu yophwanyidwa yofunikira pagawo lililonse ndiyokwera kwambiri.Zosefera zina za ma molekyulu zokhala ndi mikanda zimapereka kutentha pang'ono motero kumachepetsa mphamvu zomwe zimafunikira pakukonzanso.
Ubwino wina wogwiritsa ntchito sieve za ma molekyulu okhala ndi mikanda ndi kuchuluka kwa kachulukidwe komwe kumakhala kokulirapo kuposa mawonekedwe ena, motero pakufunika kofananira ndi kuchuluka kwa sieve ya molekyulu yofunikira ndiyocheperako.Chifukwa chake, pochita de-bottlenecking, munthu atha kugwiritsa ntchito sieve ya molekyulu yokhala ndi mikanda, kutsitsa ma adsorbent mu voliyumu yomweyo, ndikupewa kusintha kulikonse.
Nthawi yotumiza: Jul-18-2023
