I-Cellulose yi-polysaccharide eyinkimbinkimbi eyenziwe ziiyunithi ezininzi zeglucose ezidityaniswe ziibhondi ze-β-1,4-glycosidic. Yinto ephambili kwiindonga zeeseli zezityalo kwaye inika iindonga zeeseli zezityalo inkxaso eqinileyo yesakhiwo kunye nokuqina. Ngenxa yetsheyini ende yemolekyuli ye-cellulose kunye ne-crystallinity ephezulu, izinzile kwaye ayinyibiliki.
(1) Iimpawu ze-cellulose kunye nobunzima bokunyibilika
I-Cellulose ineempawu ezilandelayo ezenza kube nzima ukunyibilika:
Ubukhristalo obuphezulu: Iitsheyini zemolekyuli ze-cellulose zenza isakhiwo se-lattice esiqinileyo ngokusebenzisa iibhondi ze-hydrogen kunye nemikhosi ye-van der Waals.
Inqanaba eliphezulu le-polymerization: Inqanaba le-polymerization (oko kukuthi, ubude be-molecular chain) ye-cellulose liphezulu, lidla ngokuqala kumakhulu ukuya kumawaka eeyunithi ze-glucose, nto leyo enyusa ukuzinza kwe-molecule.
Inethiwekhi yebhondi yeHydrogen: Iibhondi zeHydrogen zifumaneka ngokubanzi phakathi nangaphakathi kweetsheyini zeemolekyuli zecellulose, nto leyo eyenza kube nzima ukutshatyalaliswa nokunyibilikiswa zizinyibilikisi eziqhelekileyo.
(2) Izinto ezinyibilikisa i-cellulose
Okwangoku, ii-reagents ezaziwayo ezinokunyibilikisa i-cellulose ngempumelelo ziquka ezi ndidi zilandelayo:
1. Ulwelo lwe-Ionic
Ii-ionic liquids zizinto ezidityaniswe nee-organic cations kunye nee-anions ze-organic okanye ezingaphiliyo, zihlala zine-volatility ephantsi, uzinzo oluphezulu lobushushu kunye nokulungelelaniswa okuphezulu. Ezinye ii-ionic liquids zinokunyibilikisa i-cellulose, kwaye indlela ephambili kukwaphula ii-hydrogen bonds phakathi kwee-cellulose molecular chains. Ii-ionic liquids eziqhelekileyo ezinyibilikisa i-cellulose ziquka:
I-1-Butyl-3-methylimidazolium chloride ([BMIM]Cl): Olu lwelo lwe-ionic lunyibilikisa i-cellulose ngokusebenzisana neebhondi ze-hydrogen kwi-cellulose ngokusebenzisa ii-hydrogen bond acceptors.
I-1-Ethyl-3-methylimidazolium acetate ([EMIM][Ac]): Olu lwelo lwe-ionic lunokunyibilikisa amazinga aphezulu e-cellulose phantsi kweemeko ezibuthathaka.
2. Isisombululo se-amine oxidant
Isisombululo se-amine oxidant esifana nesisombululo esixutyiweyo se-diethylamine (DEA) kunye ne-copper chloride sibizwa ngokuba yi-[Cu(II)-ammonium solution], esisixombululo esinamandla esinokunyibilikisa i-cellulose. Sitshabalalisa isakhiwo sekristale se-cellulose nge-oxidation kunye ne-hydrogen bonding, okwenza i-cellulose molecular chain ithambe kwaye inyibilike ngakumbi.
3. Inkqubo yeLithium chloride-dimethylacetamide (LiCl-DMac)
Inkqubo yeLiCl-DMAc (lithium chloride-dimethylacetamide) yenye yeendlela zakudala zokunyibilikisa i-cellulose. I-LiCl inokwenza ukhuphiswano lweebhondi ze-hydrogen, ngaloo ndlela itshabalalise inethiwekhi yebhondi ye-hydrogen phakathi kweemolekyuli ze-cellulose, ngelixa i-DMAc njenge-solvent inokunxibelelana kakuhle ne-cellulose molecular chain.
4. Isisombululo se-Hydrochloric acid/zinc chloride
Isisombululo se-hydrochloric acid/zinc chloride sisixhobo esafunyanwa kwangoko esinokunyibilikisa i-cellulose. Sinokunyibilikisa i-cellulose ngokwenza isiphumo sokudibanisa phakathi kwe-zinc chloride kunye ne-cellulose molecular chains, kwaye i-hydrochloric acid itshabalalise ii-hydrogen bonds phakathi kwee-molecules ze-cellulose. Nangona kunjalo, esi sisombululo siyingozi kakhulu kwizixhobo kwaye silinganiselwe kwizicelo ezisebenzayo.
5. Ii-enzymes ze-Fibrinolytic
Ii-enzymes ze-fibrinolytic (ezifana nee-cellulases) zinyibilikisa i-cellulose ngokubangela ukubola kwe-cellulose ibe zii-oligosaccharides ezincinci kunye nee-monosaccharides. Le ndlela ineendlela ezininzi zokusetyenziswa kwiindawo zokubola kwe-biogradation kunye nokuguqulwa kwe-biomass, nangona inkqubo yayo yokunyibilikisa ingekuko ukunyibilika ngokupheleleyo kweekhemikhali, kodwa ifezekiswa nge-biocatalysis.
(3) Indlela yokunyibilika kweselilulose
Ii-reagents ezahlukeneyo zineendlela ezahlukeneyo zokunyibilikisa i-cellulose, kodwa ngokubanzi zinokubangelwa ziindlela ezimbini eziphambili:
Ukutshatyalaliswa kweebhondi zehydrogen: Ukutshabalalisa iibhondi zehydrogen phakathi kweetsheyini zemolekyuli zecellulose ngokwakhiwa kwebhondi yehydrogen ekhuphisanayo okanye ukusebenzisana kwe-ionic, okwenza ukuba inyibilike.
Ukuphumla kwe-molecular chain: Ukwandisa ukuthamba kwe-cellulose molecular chains kunye nokunciphisa i-crystallinity ye-molecular chains ngeendlela zomzimba okanye zeekhemikhali, ukuze zinyibilike kwi-solvents.
(4) Ukusetyenziswa okusebenzayo kokunyibilika kweselilulose
Ukunyibilika kweseli kunezicelo ezibalulekileyo kwiindawo ezininzi:
Ukulungiswa kwezinto eziphuma kwi-cellulose: Emva kokunyibilikisa i-cellulose, ingatshintshwa ngakumbi ngokweekhemikhali ukuze kulungiswe ii-cellulose ethers, ii-cellulose esters kunye nezinye izinto eziphuma kuyo, ezisetyenziswa kakhulu ekutyeni, kumayeza, kwiingubo nakwezinye iindawo.
Izinto ezisekelwe kwi-cellulose: Ukusebenzisa i-cellulose enyibilikisiweyo, ii-nanofibers ze-cellulose, ii-membranes ze-cellulose kunye nezinye izinto zinokulungiswa. Ezi zinto zineempawu ezilungileyo zoomatshini kunye nokuhambelana kwezinto eziphilayo.
Amandla e-biomass: Ngokunyibilikisa nokonakalisa i-cellulose, ingaguqulwa ibe ziishukela ezinokubila ukuze kuveliswe ii-biofuels ezifana ne-bioethanol, enceda ekuphuhliseni nasekusebenziseni amandla avuselelekayo.
Ukunyibilika kweselilulose yinkqubo entsonkothileyo equka iindlela ezininzi zamakhemikhali nezomzimba. Ii-ionic liquids, izisombululo ze-amino oxidant, iinkqubo ze-LiCl-DMAc, izisombululo ze-hydrochloric acid/zinc chloride kunye nee-enzymes ze-cellolytic okwangoku zaziwa njengeearhente ezisebenzayo zokunyibilikisa i-cellulose. Iarhente nganye inendlela yayo eyahlukileyo yokunyibilikisa kunye nentsimi yesicelo. Ngophando olunzulu lwendlela yokunyibilikisa i-cellulose, kukholelwa ukuba iindlela zokunyibilikisa ezisebenzayo nezinobuhlobo nokusingqongileyo ziya kuphuhliswa, zibonelele ngamathuba amaninzi okusetyenziswa kunye nokuphuhliswa kwe-cellulose.
Ixesha leposi: Julayi-09-2024