I-Cellulose, eyona polymer ininzi yezinto eziphilayo emhlabeni, yenza inxalenye ebalulekileyo ye-biomass kunye nezixhobo ezahlukeneyo zemizi-mveliso.Ubume bayo obumangalisayo bobume bubeka imiceli mngeni ekuwohlokeni kwayo ngokufanelekileyo, okubalulekileyo kwizicelo ezifana nokuveliswa kwe-biofuel kunye nolawulo lwenkunkuma.I-hydrogen peroxide (H2O2) iye yavela njengomviwa onokuthi uchithe i-cellulose ngenxa yendalo yayo enobungozi kunye neempawu ze-oxidizing.
Intshayelelo:
I-Cellulose, i-polysaccharide eyenziwe ngeeyunithi ze-glucose ezidityaniswe yi-β-1,4-glycosidic bond, iyona nxalenye enkulu yesakhiwo kwiindonga zeeseli zezityalo.Ubuninzi bayo kwi-biomass buyenza ibe sisixhobo esinomtsalane kumashishini ahlukeneyo, kubandakanya iphepha kunye ne-pulp, amalaphu, kunye ne-bioenergy.Nangona kunjalo, uthungelwano oluqinileyo lwe-hydrogen bonding ngaphakathi kwe-cellulose fibrils luyenza imelane nokunyibilika kwezona zinyibilikisiweyo zininzi, ibeka imiceli mngeni ekusebenziseni kwayo ngokufanelekileyo kunye nokurisayikilisha.
Iindlela zemveli zokuchithwa kwe-cellulose zibandakanya iimeko ezinzima, ezifana ne-acids concentrated okanye i-ionic liquids, ezihlala zihambelana neenkxalabo zokusingqongileyo kunye nokusetyenziswa kwamandla aphezulu.Ngokwahlukileyo, i-hydrogen peroxide ibonelela ngenye indlela ethembisayo ngenxa yobume bayo obuthambileyo bokwenza i-oxidizing kunye nokubanakho ukusetyenzwa kweselulosi ehambelana nokusingqongileyo.Eli phepha lihlolisisa iindlela eziphantsi kwe-hydrogen peroxide-mediated cellulose dissolution kwaye ivavanya ukusebenza kwayo kunye nokusetyenziswa okusebenzayo.
IiNdlela zokuNcitshiswa kweSelulosi ngeHydrogen Peroxide:
Ukuchithwa kwe-cellulose nge-hydrogen peroxide kubandakanya ukuphendulwa kweekhemikhali eziyinkimbinkimbi, ngokuyinhloko i-oxidative cleavage yamabhondi e-glycosidic kunye nokuphazamiseka kwe-intermolecular hydrogen bonding.Inkqubo idla ngokuqhubeka ngala manyathelo alandelayo:
I-Oxidation ye-Hydroxyl Groups: I-hydrogen peroxide idibana kunye namaqela e-cellulose hydroxyl, ekhokelela ekuyilweni kwee-radicals ze-hydroxyl (•OH) nge-Fenton okanye i-Fenton-like reactions kubukho bee-ion zentsimbi eziguqukayo.Ezi radicals zihlasela iibhondi ze-glycosidic, ziqalisa i-chain scission kwaye zivelise amaqhekeza amafutshane e-cellulose.
Ukuphazamiseka kwe-Hydrogen Bonding: I-Hydroxyl radicals iphinda iphazamise inethiwekhi ye-hydrogen bonding phakathi kwamatyathanga e-cellulose, yenza buthathaka isakhiwo esipheleleyo kunye nokuququzelela isisombululo.
Ukuqulunqwa kwe-Soluble Derivatives: Ukutshatyalaliswa kwe-oxidative ye-cellulose kubangela ukubunjwa kwe-intermediates e-soluble yamanzi, njenge-carboxylic acids, i-aldehydes, kunye ne-ketones.Ezi ziphuma zinegalelo kwinkqubo yokutshatyalaliswa ngokunyusa ukunyibilika kunye nokunciphisa i-viscosity.
I-Depolymerization kunye noKwahlulwa: Okunye oxidation kunye nokuqhekeka ukuphendula kukhokelela ekudityanisweni kwekhonkco leselulosi kwiioligomers ezimfutshane kwaye ekugqibeleni kwiswekile enyibilikayo okanye ezinye iimveliso ezinobunzima obuphantsi bemolekyuli.
Izinto ezichaphazela ukuNyulwa kweSelulosi yeHydrogen Peroxide-Mediated:
Ukusebenza kokunyibilikiswa kweselulosi kusetyenziswa ihydrogen peroxide kuphenjelelwa zizinto ezahlukeneyo, eziquka:
Ukuxinana kwePeroxide yeHydrojeni: Ukuxinana okuphezulu kwehydrogen peroxide kudla ngokukhokelela kumazinga okusabela ngokukhawuleza kunye nokuthotywa okubanzi kweselulosi.Nangona kunjalo, ukugxila okuphezulu kakhulu kunokukhokelela ekuphenduleni okusecaleni okanye kwiimveliso ezingafunekiyo.
i-pH kunye noBushushu: I-pH ye-reaction medium ichaphazela ukuveliswa kwee-radicals ze-hydroxyl kunye nokuzinza kwe-cellulose derivatives.Iimeko ze-acidic ephakathi (pH 3-5) zihlala zikhethwa ukwandisa ukunyibilika kwe-cellulose ngaphandle kokuthotywa okukhulu.Ukongeza, ubushushu buchaphazela i-reaction kinetics, kunye namaqondo obushushu aphezulu ngokubanzi akhawulezisa inkqubo yokupheliswa.
Ubukho beCatalysts: Ii-ion zetsimbi zenguqu, ezifana nentsimbi okanye ubhedu, zinokubangela ukubola kwe-hydrogen peroxide kwaye ziphucule ukubunjwa kwe-hydroxyl radicals.Nangona kunjalo, ukhetho lwe-catalyst kunye nokugxininiswa kwayo kufuneka kulungiswe ngononophelo ukunciphisa ukuphendula kwamacala kunye nokuqinisekisa umgangatho wemveliso.
I-Cellulose Morphology kunye neCrystallinity: Ukufikeleleka kwamatyathanga e-cellulose kwi-hydrogen peroxide kunye ne-hydroxyl radicals kuphenjelelwa yi-morphology yezinto kunye ne-crystalline structure.Imimandla ye-Amorphous isengozini yokuthotywa kunemimandla yekristale ephezulu, efuna unyango lwangaphambili okanye izicwangciso zokuguqula ukuphucula ukufikeleleka.
Izinto eziluncedo kunye nezicelo zeHydrogen Peroxide kwiCellulose Dissolution:
Iperoxide yehidrojeni ibonelela ngeengenelo ezininzi zokunyibilikiswa kweselulosi xa kuthelekiswa neendlela eziqhelekileyo:
Ukuhambelana kokusiNgqongileyo: Ngokungafaniyo neekhemikhali ezibukhali ezifana ne-asidi yesulfuric okanye izinyibilikisi ezineklorini, i-hydrogen peroxide ayinabungozi kwaye ibola emanzini nakwi-oxygen phantsi kweemeko ezithambileyo.Olu phawu lwenza ukuba lulungele ukusetyenzwa kweselulosi ezinzileyo kunye nokulungiswa kwenkunkuma.
Iimeko Zokusabela Ezilula: Ukuchithwa kweselulosi ye-hydrogen peroxide-mediated kunokwenziwa phantsi kweemeko ezithambileyo zobushushu kunye noxinzelelo, ukunciphisa ukusetyenziswa kwamandla kunye neendleko zokusebenza xa kuthelekiswa nobushushu obuphezulu be-acid hydrolysis okanye unyango lwe-ionic liquid.
I-Oxidation ekhethiweyo: I-oxidative cleavage yeebhondi ze-glycosidic nge-hydrogen peroxide inokulawulwa kwinqanaba elithile, ivumela ukuguqulwa okukhethiweyo kwamatyathanga e-cellulose kunye nokuveliswa kwezinto ezixutywe kunye neempawu ezithile.
Ukusetyenziswa kwezinto ezininzi: I-soluble cellulose derivatives efunyenwe kwi-hydrogen peroxide-mediated dissolution inezicelo ezinokubakho kwiinkalo ezahlukeneyo, kubandakanywa ukuveliswa kwe-biofuel, izinto ezisebenzayo, izixhobo ze-biomedical, kunye nokucocwa kwamanzi amdaka.
Imiceli mngeni kunye nezikhokelo zexesha elizayo:
Ngaphandle kweempawu zayo ezithembisayo, ukuchithwa kweselulosi ye-hydrogen peroxide-mediated ijongene nemingeni emininzi kunye neendawo zokuphucula:
Ukukhetha kunye neSivuno: Ukufumana izivuno eziphezulu ze-soluble cellulose derivatives kunye neempendulo ezincinci zecala kuhlala kungumngeni, ngakumbi kwi-biomass feedstocks ene-lignin kunye ne-hemicellulose.
I-Scale-Up and Process Integration: Ukunyuswa kweenkqubo zokuchithwa kwe-cellulose esekwe kwi-hydrogen peroxide kumanqanaba emizi-mveliso kufuna uqwalaselo olucokisekileyo loyilo lwe-reactor, ukubuyiswa kwe-solvent, kunye namanyathelo okuqhuba ezantsi ukuze kuqinisekiswe ukubakho koqoqosho kunye nokuzinza kokusingqongileyo.
Uphuhliso lwe-Catalyst: Uyilo lwee-catalysts ezisebenzayo zokuvula i-hydrogen peroxide kunye ne-cellulose oxidation ibalulekile ekuphuculeni izinga lokuphendula kunye nokukhetha ngelixa kuncitshiswa ukulayishwa kwe-catalyst kunye nokwakhiwa kwemveliso.
I-Valorization ye-By-Products: Ubuchule bokwenza ixabiso lemveliso eyenziwe nge-hydrogen peroxide-mediated cellulose ukuchithwa, njenge-carboxylic acids okanye i-oligomeric sugars, inokuphucula ngakumbi uzinzo kunye nokusebenza koqoqosho kwenkqubo.
Iperoxide yehidrojeni inesithembiso esibalulekileyo njengesinyibilikisi esiluhlaza nesiguquguqukayo sokunyibilika kweselulosi, enika iingenelo ezifana nokuhambelana nokusingqongileyo, iimeko zokusabela kancinci, kunye ne-oxidation ekhethiweyo.Nangona kukho imingeni eqhubekayo, iinzame zophando eziqhubekayo ezijolise ekucaciseni iindlela ezisisiseko, ukulungelelanisa iiparamitha zokusabela, kunye nokuhlola izicelo ezintsha kuya kuphucula ngakumbi ukwenzeka kunye nokuzinza kweenkqubo ezisekelwe kwi-hydrogen peroxide ye-cellulose valorization.
Ixesha lokuposa: Apr-10-2024