Izisefu zemolekyulizizinto ezibalulekileyo zokwahlula igesi kunye nolwelo kunye nokucocwa kumashishini ahlukeneyo. Ziyi-crystalline metalloaluminosilicates ezinemibhobho efanayo ekhetha iimolekyuli ze-adsorb ngokusekelwe kubukhulu kunye nokumila kwazo. Iinkqubo yokuvelisa i-molecular sievesibandakanya amanyathelo amaninzi antsonkothileyo okuqinisekisa ukuveliswa kwezinto ezikumgangatho ophezulu ezinobukhulu obuthile bepore kunye neempawu.
Ukuveliswa kwee-sieves ze-molecular kuqala ngokukhethwa kwezinto ezibonakalayo, kuquka i-sodium silicate, i-alumina kunye namanzi. Ezi zixhobo zixutywe ngomlinganiselo ochanekileyo ukuze zenze i-gel ye-homogeneous, ethi ke ixhomekeke kwinkqubo ye-hydrothermal synthesis. Kule nyathelo, i-gel ishushu kwiqondo lokushisa eliphezulu phambi kwezinto ze-alkaline ukukhuthaza ukubunjwa kwesakhiwo se-crystal kunye neepores ezifanayo.
Isigaba esilandelayo esibalulekileyo kwinkqubo yokuvelisa i-ion exchange, ebandakanya ukutshintshwa kwe-sodium ions kwisakhiwo se-crystal kunye nezinye i-cations ezifana ne-calcium, i-potassium okanye i-magnesium. Le nkqubo yokutshintshiselana nge-ion ibaluleke kakhulu ekulawuleni ukusebenza kwee-molecular sieves, kubandakanywa amandla e-adsorption kunye nokukhetha. Uhlobo lwe-cation olusetyenziselwa ukutshintshana kwe-ion luxhomekeke kwiimfuno ezithile zesicelo se-molecular sieve.
Emva kokutshintshiselana kwe-ion, i-sieves ye-molecular idlula uchungechunge lwamanyathelo okuhlamba kunye nokomisa ukususa nakuphi na ukungcola kunye neekhemikhali ezishiyekileyo kwinkqubo yokuvelisa. Oku kuqinisekisa ukuba imveliso yokugqibela ihlangabezana nemigangatho engqongqo yokucoceka efunekayo kwizicelo zamashishini. Emva kokuba inkqubo yokuhlamba kunye nokomisa igqityiwe, i-molecular sieves i-calcined kumaqondo okushisa aphezulu ukuzinzisa isakhiwo se-crystal kwaye isuse nayiphi na i-organic compounds eseleyo.
Inyathelo lokugqibela kwinkqubo yokuvelisa libandakanya ukusebenza kweesefu zemolekyuli ukuzilungiselela izicelo ze-adsorption. Le nkqubo yokuvula ibandakanya ukufudumeza ii-molecular sievekumaqondo obushushu aphezulu ukususa ukufuma kunye nokuphucula iimpawu zayo ze-adsorption. Ubude bexesha kunye nobushushu benkqubo yokuvula kulawulwa ngononophelo ukufezekisa ubungakanani obufunwayo bepore kunye nommandla womphezulu we-molecular sieve.
I-Sieves ye-molecular ifumaneka ngobukhulu obuhlukeneyo be-pore, kuquka i-3A, i-4A kunye ne-5A, nganye ifanelekile kwizicelo ezithile. Umzekelo,3Izisefu zemolekyulizihlala zisetyenziselwa ukuphelelwa ngamanzi emzimbeni kweegesi kunye nolwelo, ngelixaI-4A kunye ne-5A iisefu ze-molecularzikhethwa ukuthengisa iimolekyuli ezinkulu kunye nokususa ukungcola okufana namanzi kunye necarbon dioxide.
Isishwankathelo, ukwenziwa kweesefu zemolekyuli yinkqubo entsonkothileyo nentsonkothileyo ebandakanya amanyathelo aphambili aliqela, kubandakanywa ne-hydrothermal synthesis, utshintsho lwe-ion, ukuhlamba, ukomisa, ukubala, kunye nokusebenza. La manyathelo alawulwa ngononophelo ukuvelisaiisefu zemolekyuliezineepropati ezilungiselelweyo kunye nobukhulu bepore ukuhlangabezana neemfuno ezahlukeneyo zamashishini afana nepetrochemical, amayeza kunye nokusetyenzwa kwegesi yendalo. Umgangatho ophezuluiisefu zemolekyuli zenziwengabavelisi abahloniphekileyo badlala indima ebalulekileyo ekufezekiseni ulwahlulo olusebenzayo kunye neenkqubo zokucoca kwizicelo ezahlukeneyo zoshishino.
Ixesha lokuposa: Apr-19-2024