Cellulose, yog cov organic polymer uas muaj ntau tshaj plaws hauv ntiaj teb, yog ib feem tseem ceeb ntawm cov biomass thiab ntau yam khoom siv hauv kev lag luam. Nws cov qauv zoo kawg nkaus ua rau muaj kev cov nyom rau nws txoj kev tawg ua haujlwm zoo, tseem ceeb rau cov ntawv thov xws li kev tsim roj biofuel thiab kev tswj cov khib nyiab. Hydrogen peroxide (H2O2) tau tshwm sim ua tus neeg sib tw rau kev yaj cellulose vim nws qhov xwm txheej tsis ua rau ib puag ncig puas tsuaj thiab cov khoom oxidizing.
Kev Taw Qhia:
Cellulose, ib qho polysaccharide uas muaj cov glucose units txuas nrog los ntawm β-1,4-glycosidic bonds, yog ib qho tseem ceeb ntawm cov qauv hauv cov phab ntsa cell ntawm cov nroj tsuag. Nws muaj ntau yam biomass ua rau nws yog ib qho chaw zoo rau ntau yam lag luam, suav nrog ntawv thiab pulp, textiles, thiab bioenergy. Txawm li cas los xij, lub network hydrogen bonding muaj zog hauv cellulose fibrils ua rau nws tiv taus kev yaj hauv feem ntau cov kuab tshuaj, ua rau muaj kev cov nyom rau nws siv thiab rov ua dua tshiab.
Cov txheej txheem ib txwm muaj rau kev yaj cellulose suav nrog cov xwm txheej hnyav, xws li cov kua qaub concentrated lossis cov kua ionic, uas feem ntau cuam tshuam nrog kev txhawj xeeb txog ib puag ncig thiab kev siv hluav taws xob ntau. Qhov sib txawv, hydrogen peroxide muab lwm txoj hauv kev zoo vim nws qhov xwm txheej oxidizing me me thiab muaj peev xwm rau kev ua cov cellulose uas zoo rau ib puag ncig. Daim ntawv no tshawb nrhiav cov txheej txheem hauv qab hydrogen peroxide-mediated cellulose yaj thiab ntsuas nws cov txiaj ntsig thiab kev siv tau.
Cov txheej txheem ntawm Cellulose yaj los ntawm Hydrogen Peroxide:
Kev yaj ntawm cellulose los ntawm hydrogen peroxide cuam tshuam nrog cov tshuaj lom neeg nyuaj, feem ntau yog oxidative cleavage ntawm glycosidic bonds thiab kev cuam tshuam ntawm intermolecular hydrogen bonding. Cov txheej txheem feem ntau ua raws li cov kauj ruam hauv qab no:
Kev Oxidation ntawm Hydroxyl Pawg: Hydrogen peroxide reacts nrog cellulose hydroxyl pawg, ua rau muaj hydroxyl radicals (•OH) los ntawm Fenton lossis Fenton-zoo li cov tshuaj tiv thaiv nyob rau hauv lub xub ntiag ntawm cov hlau ions hloov pauv. Cov radicals no tawm tsam cov glycosidic bonds, pib cov saw hlau scission thiab tsim cov cellulose fragments luv dua.
Kev Cuam Tshuam ntawm Hydrogen Bonding: Hydroxyl radicals kuj cuam tshuam lub network hydrogen bonding ntawm cellulose saw, ua rau lub zog tag nrho ntawm cov qauv thiab pab txhawb kev daws teeb meem.
Kev Tsim Cov Khoom Siv Uas Yaj Tau: Kev puas tsuaj ntawm cellulose ua rau muaj cov khoom siv uas yaj tau hauv dej, xws li carboxylic acids, aldehydes, thiab ketones. Cov khoom siv no pab txhawb rau cov txheej txheem yaj los ntawm kev ua kom yaj tau thiab txo qhov viscosity.
Depolymerization thiab Fragmentation: Cov tshuaj oxidation thiab cleavage ntxiv ua rau depolymerization ntawm cellulose saw hlau mus rau hauv cov oligomers luv dua thiab thaum kawg rau cov suab thaj soluble lossis lwm yam khoom qis-molecular-weight.
Cov Yam Cuam Tshuam Rau Hydrogen Peroxide-Mediated Cellulose Dissolution:
Qhov ua tau zoo ntawm kev yaj cellulose siv hydrogen peroxide yog cuam tshuam los ntawm ntau yam, suav nrog:
Kev Ntsuas ntawm Hydrogen Peroxide: Kev ntsuas ntau ntawm hydrogen peroxide feem ntau ua rau muaj kev cuam tshuam sai dua thiab kev puas tsuaj ntawm cellulose ntau dua. Txawm li cas los xij, kev ntsuas ntau dhau yuav ua rau muaj kev cuam tshuam lossis cov khoom tsis xav tau.
pH thiab Kub: pH ntawm cov tshuaj tiv thaiv cuam tshuam rau kev tsim cov hydroxyl radicals thiab kev ruaj khov ntawm cellulose derivatives. Cov xwm txheej acidic nruab nrab (pH 3-5) feem ntau nyiam kom txhim kho cellulose solubility yam tsis muaj kev puas tsuaj loj. Tsis tas li ntawd, kub cuam tshuam rau kinetics tshuaj tiv thaiv, nrog rau qhov kub siab dua feem ntau ua kom cov txheej txheem yaj sai dua.
Muaj Cov Catalysts: Cov hlau hloov pauv ions, xws li hlau lossis tooj liab, tuaj yeem ua rau cov hydrogen peroxide lwj thiab ua rau cov hydroxyl radicals ntau ntxiv. Txawm li cas los xij, kev xaiv cov catalyst thiab nws cov concentration yuav tsum tau ua tib zoo kom txo cov kev tsis haum thiab xyuas kom meej tias cov khoom zoo.
Cellulose Morphology thiab Crystallinity: Kev nkag mus rau cov saw hlau cellulose rau hydrogen peroxide thiab hydroxyl radicals yog cuam tshuam los ntawm cov khoom siv morphology thiab cov qauv crystalline. Cov cheeb tsam amorphous muaj kev phom sij rau kev puas tsuaj ntau dua li cov cheeb tsam crystalline heev, uas yuav tsum tau ua ntej kev kho mob lossis kev hloov kho kom txhim kho kev nkag mus tau.
Cov Zoo thiab Cov Kev Siv ntawm Hydrogen Peroxide hauv Cellulose Dissolution:
Hydrogen peroxide muaj ntau qhov zoo rau kev yaj cellulose piv rau cov txheej txheem ib txwm muaj:
Kev Sib Haum Xeeb Ib Puag Ncig: Tsis zoo li cov tshuaj lom neeg hnyav xws li sulfuric acid lossis cov kuab tshuaj chlorinated, hydrogen peroxide tsis muaj teeb meem thiab lwj mus ua dej thiab oxygen hauv qab qhov xwm txheej tsis hnyav. Tus cwj pwm zoo rau ib puag ncig no ua rau nws tsim nyog rau kev ua cov cellulose thiab kev kho cov khib nyiab.
Cov Xwm Txheej Me Me: Kev yaj cov cellulose uas siv hydrogen peroxide ua ke tuaj yeem ua tiav hauv qab qhov kub thiab txias me me, txo kev siv hluav taws xob thiab cov nqi ua haujlwm piv rau kev siv kua qaub hydrolysis kub lossis kev kho kua ionic.
Kev Xaiv Oxidation: Qhov oxidative cleavage ntawm glycosidic bonds los ntawm hydrogen peroxide tuaj yeem tswj tau qee qhov, tso cai rau kev hloov kho xaiv ntawm cellulose saw thiab kev tsim cov derivatives nrog cov khoom tshwj xeeb.
Kev Siv Tau Ntau Yam: Cov cellulose derivatives uas yaj tau los ntawm kev yaj hydrogen peroxide muaj peev xwm siv tau rau ntau qhov chaw, suav nrog kev tsim cov roj biofuel, cov ntaub ntawv ua haujlwm, cov khoom siv biomedical, thiab kev kho cov dej khib nyiab.
Cov Teeb Meem thiab Cov Lus Qhia Yav Tom Ntej:
Txawm hais tias nws muaj cov yam ntxwv zoo, kev yaj ntawm cellulose uas siv hydrogen peroxide ntsib ntau yam teeb meem thiab cov chaw uas yuav tsum tau txhim kho:
Kev Xaiv thiab Kev Tawm: Kev ua tiav cov txiaj ntsig siab ntawm cov cellulose derivatives uas yaj tau nrog tsawg kawg cov kev tsis haum tshua tseem yog qhov nyuaj, tshwj xeeb tshaj yog rau cov khoom noj biomass nyuaj uas muaj lignin thiab hemicellulose.
Kev Nce Qib thiab Kev Koom Ua Ke ntawm Cov Txheej Txheem: Kev nce qib ntawm cov txheej txheem yaj cellulose uas siv hydrogen peroxide mus rau theem kev lag luam yuav tsum tau xav txog kev tsim cov reactor, kev rov qab tau cov kuab tshuaj, thiab cov kauj ruam ua tiav kom ntseeg tau tias muaj kev lag luam zoo thiab kev ruaj khov ntawm ib puag ncig.
Kev Tsim Kho Catalyst: Kev tsim cov catalysts zoo rau kev ua kom hydrogen peroxide ua haujlwm thiab cellulose oxidation yog qhov tseem ceeb rau kev txhim kho cov nqi tshuaj tiv thaiv thiab kev xaiv thaum txo qis kev thauj khoom catalyst thiab cov khoom tsim tawm.
Kev Txhim Kho Cov Khoom Siv Los Ntawm Lwm Yam: Cov tswv yim rau kev txhim kho cov khoom siv los ntawm lwm yam uas tsim los thaum lub sijhawm hydrogen peroxide-mediated cellulose yaj, xws li carboxylic acids lossis oligomeric sugars, tuaj yeem txhim kho qhov kev ruaj khov thiab kev lag luam ntawm cov txheej txheem.
Hydrogen peroxide muaj kev cia siab tseem ceeb ua ib qho tshuaj ntsuab thiab siv tau ntau yam rau kev yaj cellulose, muab cov txiaj ntsig xws li kev sib haum xeeb ntawm ib puag ncig, cov xwm txheej tsis tshua muaj zog, thiab kev xaiv oxidation. Txawm hais tias muaj kev cov nyom tseem ceeb, kev tshawb fawb txuas ntxiv mus uas tsom mus rau kev piav qhia txog cov txheej txheem hauv qab, kev ua kom zoo dua cov kev ntsuas tshuaj, thiab kev tshawb nrhiav cov ntawv thov tshiab yuav ua rau muaj kev ua tau zoo thiab kev ruaj khov ntawm cov txheej txheem hydrogen peroxide rau kev ua kom cellulose muaj nqis.
Lub sijhawm tshaj tawm: Plaub Hlis-10-2024