Izisefu zemolekyulizizinto ezibalulekileyo ezisetyenziswa kwiinkqubo ezahlukeneyo zoshishino zokwahlula iimolekyuli ngokusekelwe kubukhulu kunye nokumila kwazo. Ziyi-crystalline metal aluminosilicates kunye nothungelwano lwe-alumina kunye ne-silica tetrahedra. Eyona isetyenziswa kakhuluiisefu zemolekyulizi-3A kunye ne-4A, ezohlukileyo ngobukhulu bazo kunye nezicelo.
I-4A i-molecular sieves inobungakanani bepore malunga ne-4 angstroms, ngelixa3Izisefu zemolekyuliube nobungakanani bepore encinci ejikeleze i-3 angstroms. Umahluko kubungakanani bepore kubangela ukuhluka kubuchule babo be-adsorption kunye nokukhetha kweeamolekyu ezahlukeneyo.4Izisefu zemolekyulizidla ngokusetyenziselwa ukuphelelwa ngamanzi emzimbeni kweegesi kunye nolwelo, kunye nokususa amanzi kwizinyibilikisi nakwirhasi yendalo. Ngakolunye uhlangothi, i-3A i-sieves ye-molecular isetyenziselwa ukuchithwa kwamanzi e-unsaturated hydrocarbons kunye ne-polar compounds.
Ukwahluka kobukhulu be-pore kuchaphazela neentlobo zeemolekyuli ezinokuthi zibhengezwe ngohlobo ngalunye lwe-molecular sieve. I-4A i-molecular sieves iyasebenza ekubhengezeni iimolekyuli ezinkulu ezifana namanzi, i-carbon dioxide, kunye ne-unsaturated hydrocarbons, ngelixa i-3A i-molecular sieves ikhetha ngakumbi kwii-molecule ezincinci ezifana namanzi, i-ammonia, kunye ne-alcohols. Olu khetho lubalulekile kwizicelo apho ukungcola okukhethekileyo kufuneka kususwe kumxube weegesi okanye ulwelo.
Enye into ebalulekileyo ekufuneka uyiqwalasele xa ukhetha phakathi3A kunye ne-4A iisefu zemolekyulikukwazi kwabo ukumelana namanqanaba ahlukeneyo okufuma. I-3A i-molecular sieves inokumelana okuphezulu nomphunga wamanzi xa kuthelekiswa ne-4A ye-molecular sieves, ibenza ukuba bafanelekele izicelo apho ubukho bomswakama buxhalabisa. Oku kwenza i-3A ye-molecular sieves ilungele ukusetyenziswa kwiinkqubo zokomisa umoya kunye negesi apho ukususwa kwamanzi kubaluleke kakhulu.
Ngokubhekiselele kwizicelo zoshishino, i-4A i-molecular sieves isetyenziswa ngokuqhelekileyo ekuveliseni i-oksijini kunye ne-nitrogen kwiinkqubo zokuhlukana komoya, kunye nokomisa iifriji kunye negesi yendalo. Ukukwazi kwabo ukususa ngokufanelekileyo amanzi kunye ne-carbon dioxide kubenza baxabiseke kwezi nkqubo. Ngakolunye uhlangothi, i-3A ye-molecular sieves ifumana ukusetyenziswa ngokubanzi ekomisweni kwee-hydrocarbons ezingenasiphelo, ezifana negesi eqhekekileyo, i-propylene, kunye ne-butadiene, kunye nokuhlanjululwa kwegesi ye-petroleum engamanzi.
Kubalulekile ukuba uqaphele ukuba ukhetho phakathi kwe-3A kunye ne-4A ye-molecular sieves ixhomekeke kwiimfuno ezithile zesicelo, kubandakanywa uhlobo lweeamolekyu eziza kubhengezwa, inqanaba lokufuma elikhoyo, kunye nokucoceka okufunwayo kwemveliso yokugqibela. Ukuqonda umahluko phakathi kwezi zihluzo zemolekyuli kubalulekile ekukhetheni olona khetho lufanelekileyo kwinkqubo ethile yoshishino.
Ekugqibeleni, ngelixa zombini3A kunye ne-4A iisefu zemolekyulizibalulekile kwiinkqubo ezahlukeneyo zokuphelelwa ngamanzi emzimbeni kunye nokucoca, ukungafani kwazo kubukhulu be-pore, ukukhetha kwe-adsorption, kunye nokuchasana nokufuma kubenza bafanelekele izicelo ezihlukeneyo. Ngokuqonda ezi yantlukwano, amashishini anokwenza izigqibo ezinolwazi malunga nokukhetha kunye nokusetyenziswa kweesefu ze-molekyuli ukwandisa iinkqubo zabo kunye nokufezekisa ukucoceka kwemveliso efunekayo.
Ixesha lokuposa: Jun-27-2024