I-Cellulose, eyona polymer yendalo ininzi kakhulu eMhlabeni, yenza inxalenye ebalulekileyo ye-biomass kunye nezixhobo ezahlukeneyo zoshishino. Ukuqina kwayo okumangalisayo kubeka imingeni ekuqhekekeni kwayo ngokufanelekileyo, okubalulekileyo kwizicelo ezifana nokuveliswa kwe-biofuel kunye nolawulo lwenkunkuma. I-hydrogen peroxide (H2O2) ivele njengeyona nto inokubangela ukunyibilika kwe-cellulose ngenxa yendalo yayo engenabungozi kokusingqongileyo kunye neempawu zokuxilisa.
Intshayelelo:
I-Cellulose, i-polysaccharide eyenziwe ziiyunithi zeglucose ezidityaniswe ziibhondi ze-β-1,4-glycosidic, yinxalenye ebalulekileyo yolwakhiwo kwiindonga zeeseli zezityalo. Ubuninzi bayo kwi-biomass buyenza ibe sisixhobo esinomtsalane kumashishini ahlukeneyo, kuquka iphepha kunye ne-pulp, amalaphu, kunye ne-bioenergy. Nangona kunjalo, inethiwekhi eqinileyo ye-hydrogen bonding ngaphakathi kwi-cellulose fibrils iyenza imelane nokunyibilika kwiintlambululi ezininzi, nto leyo ebangela imingeni ekusebenziseni kwayo ngokufanelekileyo nasekusetyenzisweni kwakhona.
Iindlela zemveli zokunyibilikisa i-cellulose ziquka iimeko ezinzima, ezifana nee-acid ezixineneyo okanye ii-ionic liquids, ezidla ngokunxulunyaniswa neenkxalabo zokusingqongileyo kunye nokusetyenziswa kwamandla aphezulu. Ngokwahlukileyo koko, i-hydrogen peroxide inika enye indlela ethembisayo ngenxa yendalo yayo ethambileyo yokuxilisa kunye nokukwazi kwayo ukucutshungulwa kwe-cellulose enobuhlobo nokusingqongileyo. Eli phepha lijonga iindlela ezisisiseko sokunyibilikisa i-cellulose ebangelwa yi-hydrogen peroxide kwaye livavanya ukusebenza kwayo kunye nokusetyenziswa kwayo okusebenzayo.
Iindlela zokunyibilika kweCellulose yiHydrogen Peroxide:
Ukunyibilika kwe-cellulose yi-hydrogen peroxide kubandakanya ukusabela okuntsonkothileyo kweekhemikhali, ngokuyintloko ukuqhekeka kwe-oxidative kwiibhondi ze-glycosidic kunye nokuphazamiseka kwebhondi ye-hydrogen ephakathi kweemolekyuli. Inkqubo idla ngokuqhubeka ngala manyathelo alandelayo:
Ukuxinana kwamaqela eHydroxyl: I-hydrogen peroxide isabela namaqela e-cellulose hydroxyl, nto leyo ekhokelela ekwakhiweni kwee-hydroxyl radicals (•OH) ngeFenton okanye ii-Fenton-like reactions xa kukho ii-ion ze-transition metal. Ezi radicals zihlasela ii-glycosidic bonds, ziqala ukuqhekeka kwe-chain kwaye zivelise iziqwenga ze-cellulose ezimfutshane.
Ukuphazamiseka kweHydrogen Bonding: IiHydroxyl radicals zikwaphazamisa inethiwekhi yehydrogen bonding phakathi kwee-cellulose chains, ziyenza buthathaka isakhiwo siphela kwaye ziququzelele ukusonjululwa.
Ukwenziwa kweeMveliso ezinyibilikayo: Ukuwohloka kwe-oxidative kwe-cellulose kubangela ukwakheka kwezinto ezinyibilikayo emanzini, ezifana nee-carboxylic acids, i-aldehydes, kunye nee-ketones. Ezi mveliso zinegalelo kwinkqubo yokunyibilika ngokunyusa ukunyibilika kunye nokunciphisa i-viscosity.
Ukususwa kwepolymerization kunye nokuqhekeka: Ukusabela okungakumbi kwe-oxidation kunye nokuqhekeka kukhokelela ekususweni kwe-cellulose chains zibe zii-oligomers ezimfutshane kwaye ekugqibeleni zibe ziishukela ezinyibilikayo okanye ezinye iimveliso ezinobunzima obuphantsi beemolekyuli.
Izinto Ezichaphazela Ukunyibilika kweHydrogen Peroxide-Mediated Cellulose:
Ukusebenza kakuhle kokuchithwa kwe-cellulose kusetyenziswa i-hydrogen peroxide kuphenjelelwa zizinto ezahlukeneyo, kuquka:
Uxinzelelo lweHydrogen Peroxide: Uxinzelelo oluphezulu lwehydrogen peroxide ludla ngokubangela amazinga okusabela akhawulezayo kunye nokonakala okukhulu kwe-cellulose. Nangona kunjalo, uxinzelelo oluphezulu kakhulu lunokubangela iziphumo ezingalindelekanga okanye iziphumo ezingafunekiyo.
i-pH kunye nobushushu: I-pH ye-reaction medium inefuthe ekuvelisweni kwee-hydroxyl radicals kunye nokuzinza kwee-cellulose derivatives. Iimeko ze-acidic eziphakathi (i-pH 3-5) zihlala zikhethwa ukuze kuphuculwe ukunyibilika kwe-cellulose ngaphandle kokuwohloka okukhulu. Ukongeza, ubushushu buchaphazela i-reaction kinetics, apho amaqondo obushushu aphezulu ngokubanzi akhawulezisa inkqubo yokunyibilika.
Ubukho beeCatalysts: Ii-ion zesinyithi eziguqukayo, ezifana nentsimbi okanye ubhedu, zinokukhuthaza ukubola kwe-hydrogen peroxide kwaye zonyuse ukwakheka kwee-hydroxyl radicals. Nangona kunjalo, ukhetho lwe-catalyst kunye noxinzelelo lwayo kufuneka luphuculwe ngononophelo ukuze kuncitshiswe iziphumo ebezingalindelekanga kwaye kuqinisekiswe umgangatho wemveliso.
Imofoloji yeSellulose kunye neCrystallinity: Ukufikeleleka kweetsheyini zecellulose kwihydrogen peroxide kunye nehydroxyl radicals kuchatshazelwa yimofoloji yezinto kunye nolwakhiwo lwekristale. Iindawo ezingafaniyo zisengozini yokuwohloka kuneendawo ezikristale kakhulu, nto leyo ebangela ukuba kufuneke unyango lwangaphambi kwexesha okanye amaqhinga okuguqula ukuphucula ukufikeleleka.
Iingenelo kunye nokusetyenziswa kweHydrogen Peroxide kwiCellulose Dissolution:
I-hydrogen peroxide ineenzuzo ezininzi zokunyibilikisa i-cellulose xa kuthelekiswa neendlela eziqhelekileyo:
Ukuhambelana kweNdalo: Ngokungafaniyo neekhemikhali ezibukhali ezifana ne-sulfuric acid okanye izinyibilikisi ze-chlorine, i-hydrogen peroxide ayinabungozi kwaye iyabola ibe ngamanzi kunye ne-oksijini phantsi kweemeko ezithambileyo. Olu phawu lunobuhlobo nokusingqongileyo lwenza ukuba ifaneleke ekucutshungulweni kwe-cellulose okuzinzileyo kunye nokulungiswa kwenkunkuma.
Iimeko Ezingashukumiyo: Ukuchithwa kwe-cellulose ebangelwa yi-hydrogen peroxide kungenziwa phantsi kweemeko ezishushu zobushushu kunye noxinzelelo, kunciphisa ukusetyenziswa kwamandla kunye neendleko zokusebenza xa kuthelekiswa nonyango lwe-acid hydrolysis yobushushu obuphezulu okanye i-ionic liquid.
Ukukhetha i-Oxidation: Ukuqhekeka kwe-oxidative kweebhondi ze-glycosidic yi-hydrogen peroxide kunokulawulwa ukuya kuthi ga kwinqanaba elithile, okuvumela ukuguqulwa okukhethiweyo kweetsheyini ze-cellulose kunye nokuveliswa kwezinto ezilungiselelwe zona ezineempawu ezithile.
Ukusetyenziswa ngeendlela ezahlukeneyo: Izinto ezinyibilikayo ze-cellulose ezifumaneka kwi-hydrogen peroxide-mediated dissolving zinokusetyenziswa kwiindawo ezahlukeneyo, kubandakanya ukuveliswa kwe-biofuel, izixhobo ezisebenzayo, izixhobo zonyango, kunye nonyango lwamanzi amdaka.
Imingeni kunye neMigqaliselo yexesha elizayo:
Nangona ineempawu ezithembisayo, ukuchithwa kwe-cellulose okubangelwa yi-hydrogen peroxide kujongana nemingeni emininzi kunye neendawo ekufuneka ziphuculwe:
Ukukhetha kunye neNzuzo: Ukufumana isivuno esiphezulu se-soluble cellulose derivatives kunye neempendulo ezincinci ezisecaleni kusengumngeni, ngakumbi kwi-complex biomass feedstocks equlethe i-lignin kunye ne-hemicellulose.
Ukwandiswa kunye nokuhlanganiswa kweNkqubo: Ukunyusa iinkqubo zokuchithwa kwe-cellulose ezisekelwe kwi-hydrogen peroxide ukuya kumanqanaba emizi-mveliso kufuna ukuqwalaselwa ngononophelo kuyilo lwe-reactor, ukubuyiswa kwe-solvent, kunye namanyathelo okucubungula asezantsi ukuqinisekisa ukuba imeko yezoqoqosho kunye nokuzinza kokusingqongileyo iyaqhubeka.
Uphuhliso lweCatalyst: Uyilo lwee-catalysts ezisebenzayo zokuvuselela i-hydrogen peroxide kunye ne-cellulose oxidation lubalulekile ekuphuculeni amazinga okusabela kunye nokukhetha ngelixa kunciphisa ukulayishwa kwe-catalyst kunye nokwakheka kwemveliso ephuma kuyo.
Ukuqinisekiswa kweeMveliso eziNgezinye: Amaqhinga okuqinisekisa ixabiso leemveliso ezingezinye eziveliswa ngexesha lokuchithwa kwe-cellulose ebangelwa yi-hydrogen peroxide, njenge-carboxylic acids okanye iiswekile ze-oligomeric, anokuphucula ngakumbi uzinzo kunye nokuphila kakuhle kwenkqubo.
I-hydrogen peroxide inesithembiso esibalulekileyo njengesinyibilikisi esiluhlaza nesinokuguquguquka ekunyibilikeni kwe-cellulose, inika iingenelo ezifana nokuhambelana nokusingqongileyo, iimeko zokusabela ezithambileyo, kunye ne-oxidation ekhethiweyo. Nangona kukho imingeni eqhubekayo, imizamo yophando eqhubekayo ejolise ekucaciseni iindlela ezisisiseko, ukuphucula iiparameter zokusabela, kunye nokuphonononga ukusetyenziswa okutsha kuya kuphucula ngakumbi ukwenzeka kunye nokuzinza kweenkqubo ezisekelwe kwi-hydrogen peroxide zokwandisa i-cellulose.
Ixesha lokuthumela: Epreli-10-2024