I-Cellulose, i-polymer eningi kakhulu eMhlabeni, yakha ingxenye ebalulekile ye-biomass kanye nezinto ezahlukahlukene zezimboni. Ukuqina kwayo okuphawulekayo kwesakhiwo kudala izinselele zokuwohloka kwayo okuphumelelayo, okubalulekile ekusetshenzisweni kwayo njengokukhiqiza uphethiloli we-biofuel kanye nokuphathwa kwemfucuza. I-hydrogen peroxide (H2O2) ivele njengethuba elingase libe khona lokuncibilika kwe-cellulose ngenxa yemvelo yayo engenabungozi emvelweni kanye nezakhiwo zayo zokuxosha.
Isingeniso:
I-Cellulose, i-polysaccharide eyakhiwe ngamayunithi e-glucose axhunywe yizibopho ze-β-1,4-glycosidic, iyisakhi esiyinhloko sesakhiwo ezindongeni zamaseli ezitshalo. Ubuningi bayo ku-biomass buyenza ibe umthombo okhangayo wezimboni ezahlukahlukene, kufaka phakathi iphepha ne-pulp, izindwangu, kanye ne-bioenergy. Kodwa-ke, inethiwekhi eqinile yokubopha i-hydrogen ngaphakathi kwe-cellulose fibrils iyenza imelane nokuncibilika ezinyibilikisini eziningi, okudala izinselele zokusetshenziswa kwayo kahle kanye nokusetshenziswa kabusha.
Izindlela zendabuko zokuncibilikisa i-cellulose zihilela izimo ezinzima, njenge-acids egxilile noma uketshezi lwe-ionic, okuvame ukuhlotshaniswa nokukhathazeka ngemvelo kanye nokusetshenziswa kwamandla aphezulu. Ngokuphambene nalokho, i-hydrogen peroxide inikeza enye indlela ethembisayo ngenxa yemvelo yayo ethambile yokuxilisa kanye nekhono lokucubungula i-cellulose enobungani nemvelo. Leli phepha lihlola izindlela ezisekela ukuncibilikisa i-cellulose okubangelwa yi-hydrogen peroxide futhi lihlola ukusebenza kwayo kanye nokusetshenziswa kwayo okusebenzayo.
Izindlela Zokuncibilika Kwe-Cellulose Yi-Hydrogen Peroxide:
Ukuncibilikiswa kwe-cellulose yi-hydrogen peroxide kuhilela ukusabela kwamakhemikhali okuyinkimbinkimbi, ikakhulukazi ukuqhekeka kwezibopho ze-glycosidic kanye nokuphazamiseka kokubopha kwe-hydrogen phakathi kwama-molecule. Inqubo ivame ukuqhubeka ngezinyathelo ezilandelayo:
Ukushiswa Kwamaqembu E-Hydroxyl: I-hydrogen peroxide isabela namaqembu e-cellulose hydroxyl, okuholela ekwakhekeni kwama-hydroxyl radicals (•OH) nge-Fenton noma ukusabela okufana ne-Fenton lapho kukhona ama-ion ensimbi aguqukayo. Lawa ma-radical ahlasela izibopho ze-glycosidic, aqale ukuqhekeka kweketanga futhi akhiqize izingcezu ze-cellulose ezimfushane.
Ukuphazamiseka Kokubopha Kwe-Hydrogen: Ama-hydroxyl radicals nawo aphazamisa inethiwekhi yokubopha i-hydrogen phakathi kwamaketanga e-cellulose, okwenza buthaka isakhiwo sonke futhi kube lula ukuxazululwa.
Ukwakheka Kwezinto Ezincibilikayo: Ukuwohloka kwe-oxidative kwe-cellulose kuphumela ekwakhekeni kwezinto ezincibilikayo emanzini, njenge-carboxylic acid, i-aldehydes, nama-ketone. Lezi zinto ezincibilikayo zinegalelo enqubweni yokuncibilika ngokwandisa ukuncibilika nokunciphisa i-viscosity.
Ukuhlukaniswa Nokuhlukaniswa: Ukusabela okwengeziwe kwe-oxidation kanye nokuqhekeka kuholela ekuhlukanisweni kwamaketanga e-cellulose abe ama-oligomer amafushane futhi ekugcineni kube ushukela oncibilikayo noma eminye imikhiqizo enesisindo esincane sama-molecule.
Izici Ezithinta Ukuncibilika Kwe-Hydrogen Peroxide-Mediated Cellulose:
Ukusebenza kahle kokuncibilikiswa kwe-cellulose kusetshenziswa i-hydrogen peroxide kuthonywa yizici ezahlukahlukene, okuhlanganisa:
Ukuhlushwa kwe-Hydrogen Peroxide: Ukuhlushwa okuphezulu kwe-hydrogen peroxide kuvame ukuholela emazingeni okusabela okusheshayo kanye nokuwohloka okukhulu kwe-cellulose. Kodwa-ke, ukuhlushwa okuphezulu kakhulu kungaholela ekuphenduleni okungekuhle noma emikhiqizweni engathandeki.
i-pH kanye nezinga lokushisa: I-pH ye-reaction medium ithonya ukukhiqizwa kwama-hydroxyl radicals kanye nokuqina kwama-cellulose derivatives. Izimo ze-acidic eziphakathi nendawo (i-pH 3-5) zivame ukuthandwa ukuze kuthuthukiswe ukuncibilika kwe-cellulose ngaphandle kokuwohloka okukhulu. Ngaphezu kwalokho, izinga lokushisa lithinta i-reaction kinetics, kanti amazinga okushisa aphezulu ngokuvamile asheshisa inqubo yokuncibilika.
Ukuba khona kwama-Catalyst: Ama-ion ensimbi aguqukayo, njengensimbi noma ithusi, angakhuthaza ukubola kwe-hydrogen peroxide futhi athuthukise ukwakheka kwama-hydroxyl radicals. Kodwa-ke, ukukhetha i-catalyst kanye nokuhlushwa kwayo kumele kulungiselelwe ngokucophelela ukuze kuncishiswe ukusabela okungekuhle nokuqinisekisa ikhwalithi yomkhiqizo.
Ukwakheka Kweseli kanye Nokwakheka Kwekristalu: Ukufinyeleleka kwamaketanga eselilulose ku-hydrogen peroxide kanye nama-hydroxyl radicals kuthonywa ukwakheka kwezinto kanye nesakhiwo sekristalu. Izindawo ezi-Amorphous zisengozini enkulu yokuwohloka kunezindawo ezinamakristalu amaningi, okudinga amasu okwelashwa kusengaphambili noma okuguqulwa ukuze kuthuthukiswe ukufinyeleleka.
Izinzuzo kanye nokusetshenziswa kwe-Hydrogen Peroxide ekuqhekekeni kwe-Cellulose:
I-hydrogen peroxide inikeza izinzuzo eziningana zokuncibilika kwe-cellulose uma kuqhathaniswa nezindlela ezivamile:
Ukuhambisana Kwemvelo: Ngokungafani namakhemikhali aqinile njenge-sulfuric acid noma izinyibilikisi ezine-chlorine, i-hydrogen peroxide ayinabungozi futhi ibola ibe ngamanzi nomoya-mpilo ngaphansi kwezimo ezithambile. Lesi sici esinobungani nemvelo senza ifanelekele ukucutshungulwa kwe-cellulose okusimeme kanye nokulungiswa kwemfucuza.
Izimo Zokusabela Okuncane: Ukuncibilikiswa kwe-cellulose okubangelwa yi-hydrogen peroxide kungenziwa ngaphansi kwezimo eziphansi zokushisa nokucindezela, kunciphisa ukusetshenziswa kwamandla kanye nezindleko zokusebenza uma kuqhathaniswa nokwelashwa kwe-acid hydrolysis ephezulu noma i-ionic liquid.
Ukwakheka kwe-oxidation okukhethiwe: Ukuqhekeka kwe-oxidative kwezibopho ze-glycosidic yi-hydrogen peroxide kungalawulwa ngezinga elithile, okuvumela ukuguqulwa okukhethiwe kwamaketanga e-cellulose kanye nokukhiqizwa kwezinto ezisuselwe ngokwezifiso ezinezakhiwo ezithile.
Ukusetshenziswa Okuguquguqukayo: Izinto ezincibilikayo ze-cellulose ezitholakala ekuncibilikisweni okubangelwa yi-hydrogen peroxide zinokusetshenziswa okungaba khona emikhakheni eyahlukahlukene, okuhlanganisa ukukhiqizwa kwe-biofuel, izinto ezisebenzayo, amadivayisi e-biomedical, kanye nokwelashwa kwamanzi amdaka.
Izinselele Neziqondiso Zesikhathi Esizayo:
Naphezu kwezimfanelo zayo ezithembisayo, ukuncibilika kwe-cellulose okubangelwa yi-hydrogen peroxide kubhekene nezinselele eziningana kanye nezindawo okufanele zithuthukiswe:
Ukukhetha kanye Nokukhiqiza: Ukuthola isivuno esikhulu sezinto ezincibilikayo ze-cellulose ezincibilikayo ezinemiphumela emibi emincane kusalokhu kuyinselele, ikakhulukazi ezitshalweni eziyinkimbinkimbi ze-biomass eziqukethe i-lignin ne-hemicellulose.
Ukuhlanganiswa Kokukhuliswa Nokukhuliswa Kwezinqubo: Ukwandisa izinqubo zokuncibilikisa i-cellulose ezisekelwe ku-hydrogen peroxide ziye emazingeni ezimboni kudinga ukucatshangelwa ngokucophelela ukwakheka kwe-reactor, ukubuyiselwa kwe-solvent, kanye nezinyathelo zokucubungula ezingezansi ukuqinisekisa ukusebenza kahle kwezomnotho kanye nokusimama kwemvelo.
Ukuthuthukiswa kwe-Catalyst: Ukwakhiwa kwama-catalyst asebenzayo okusebenza kwe-hydrogen peroxide kanye ne-cellulose oxidation kubalulekile ekuthuthukiseni amazinga okusabela kanye nokukhetha ngenkathi kunciphisa ukulayishwa kwama-catalyst kanye nokwakheka komkhiqizo olandelanayo.
Ukuqinisekiswa Kwemikhiqizo Engaphansi: Amasu okuqinisekisa imikhiqizo engaphansi ekhiqizwa ngesikhathi sokuncibilika kwe-cellulose okubangelwa yi-hydrogen peroxide, njenge-carboxylic acid noma ushukela we-oligomeric, angathuthukisa kakhulu ukusimama kanye nokusebenza kahle kwezomnotho kwale nqubo.
I-hydrogen peroxide inesithembiso esibalulekile njengesithako esiluhlaza nesiguquguqukayo sokuncibilika kwe-cellulose, enikeza izinzuzo ezifana nokuhambisana kwemvelo, izimo zokusabela okuncane, kanye ne-oxidation ekhethiwe. Naphezu kwezinselelo eziqhubekayo, imizamo yocwaningo eqhubekayo ehlose ukucacisa izindlela eziyisisekelo, ukwenza ngcono amapharamitha okusabela, kanye nokuhlola izinhlelo zokusebenza ezintsha kuzothuthukisa kakhulu ukwenzeka kanye nokusimama kwezinqubo ezisekelwe ku-hydrogen peroxide zokwandisa i-cellulose.
Isikhathi sokuthunyelwe: Ephreli-10-2024