Cellulose, feem ntau cov organic polymer nyob rau hauv lub ntiaj teb, ua ib feem tseem ceeb ntawm biomass thiab ntau yam khoom siv.Nws txoj kev ncaj ncees zoo kawg nkaus ua rau muaj teeb meem rau nws txoj kev puas tsuaj, tseem ceeb heev rau kev siv xws li biofuel ntau lawm thiab kev tswj cov khib nyiab.Hydrogen peroxide (H2O2) tau tshwm sim los ua tus neeg sib tw muaj peev xwm rau kev tshem tawm ntawm cellulose vim nws qhov xwm txheej ib puag ncig zoo thiab oxidizing zog.
Taw qhia:
Cellulose, polysaccharide tsim los ntawm cov piam thaj txuas los ntawm β-1,4-glycosidic bonds, yog ib qho tseem ceeb ntawm cov kab mob hauv cov phab ntsa ntawm cov nroj tsuag.Nws txoj kev nplua nuj nyob hauv biomass ua rau nws muaj peev xwm txaus nyiam rau ntau yam kev lag luam, suav nrog ntawv thiab pulp, textiles, thiab bioenergy.Txawm li cas los xij, lub zog hydrogen bonding network nyob rau hauv cellulose fibrils ua rau nws resistant rau dissolution nyob rau hauv feem ntau cov kuab tshuaj, possibilities rau nws npaum li cas siv thiab recycling.
Cov txheej txheem ib txwm siv rau kev tshem tawm cellulose cuam tshuam nrog cov xwm txheej hnyav, xws li cov kua qaub lossis cov kua ionic, uas feem ntau cuam tshuam nrog kev txhawj xeeb ntawm ib puag ncig thiab kev siv zog siab.Nyob rau hauv sib piv, hydrogen peroxide muaj ib qho kev cog lus lwm txoj kev vim nws qhov me me oxidizing xwm thiab muaj peev xwm rau ib puag ncig tus phooj ywg cellulose ua.Daim ntawv no delves rau hauv cov txheej txheem hauv qab ntawm hydrogen peroxide-mediated cellulose dissolution thiab ntsuas nws cov kev ua tau zoo thiab siv tau.
Mechanisms ntawm Cellulose Dissolution los ntawm Hydrogen Peroxide:
Kev tawg ntawm cellulose los ntawm hydrogen peroxide cuam tshuam cov tshuaj lom neeg cov tshuaj tiv thaiv, feem ntau oxidative cleavage ntawm glycosidic bonds thiab cuam tshuam ntawm intermolecular hydrogen bonding.Cov txheej txheem feem ntau yog ua los ntawm cov kauj ruam hauv qab no:
Oxidation ntawm Hydroxyl Pawg: Hydrogen peroxide reacts nrog cellulose hydroxyl pawg, ua rau tsim cov hydroxyl radicals (•OH) ntawm Fenton los yog Fenton zoo li cov tshuaj tiv thaiv nyob rau hauv lub xub ntiag ntawm kev hloov hlau ions.Cov radicals no tawm tsam cov glycosidic daim ntawv cog lus, pib cov saw hlau thiab tsim cov cellulose luv luv.
Kev cuam tshuam ntawm Hydrogen Bonding: Hydroxyl radicals kuj cuam tshuam cov hydrogen bonding network ntawm cellulose chains, ua kom tsis muaj zog tag nrho cov qauv thiab txhawb kev daws teeb meem.
Tsim cov Soluble Derivatives: Cov oxidative degradation ntawm cellulose ua rau tsim cov dej-soluble intermediates, xws li carboxylic acids, aldehydes, thiab ketones.Cov derivatives no pab txhawb rau cov txheej txheem kev sib cais los ntawm kev ua kom solubility thiab txo viscosity.
Depolymerization thiab Fragmentation: Ntxiv oxidation thiab cleavage tshwm sim ua rau depolymerization ntawm cellulose chains rau luv oligomers thiab thaum kawg rau soluble qab zib los yog lwm yam khoom uas tsis muaj molecular-yuag.
Yam Tseem Ceeb cuam tshuam rau Hydrogen Peroxide-Mediated Cellulose Dissolution:
Kev ua tau zoo ntawm cellulose dissolution siv hydrogen peroxide yog cuam tshuam los ntawm ntau yam, suav nrog:
Kev Cuam Tshuam ntawm Hydrogen Peroxide: Cov ntsiab lus siab dua ntawm hydrogen peroxide feem ntau ua rau cov tshuaj tiv thaiv sai dua thiab ntau dua cellulose degradation.Txawm li cas los xij, kev siv ntau dhau tuaj yeem ua rau muaj kev cuam tshuam sab lossis tsis xav tau los ntawm cov khoom lag luam.
pH thiab Kub: Lub pH ntawm cov tshuaj tiv thaiv nruab nrab cuam tshuam rau tiam ntawm hydroxyl radicals thiab stability ntawm cellulose derivatives.Cov kua qaub nruab nrab (pH 3-5) feem ntau nyiam los txhim kho cellulose solubility yam tsis muaj kev puas tsuaj loj.Tsis tas li ntawd, qhov kub thiab txias cuam tshuam rau cov tshuaj tiv thaiv kinetics, nrog rau qhov kub thiab txias feem ntau ua rau cov txheej txheem tawg.
Muaj Cov Catalysts: Hloov cov hlau ions, xws li hlau lossis tooj liab, tuaj yeem ua rau cov decomposition ntawm hydrogen peroxide thiab txhim kho kev tsim cov hydroxyl radicals.Txawm li cas los xij, kev xaiv ntawm catalyst thiab nws cov concentration yuav tsum tau ua tib zoo ua kom zoo kom txo qis kev cuam tshuam sab thiab ua kom cov khoom zoo.
Cellulose Morphology thiab Crystallinity: Kev nkag tau ntawm cellulose chains rau hydrogen peroxide thiab hydroxyl radicals yog cuam tshuam los ntawm cov khoom siv morphology thiab crystalline qauv.Cov cheeb tsam amorphous muaj kev cuam tshuam ntau dua rau kev degradation dua li cov crystalline ntau heev, xav tau kev kho ua ntej lossis hloov cov tswv yim los txhim kho kev nkag mus tau zoo.
Qhov zoo thiab kev siv ntawm Hydrogen Peroxide hauv Cellulose Dissolution:
Hydrogen peroxide muaj ntau yam zoo rau cellulose dissolution piv rau cov qauv siv:
Environmental Compatibility: Tsis zoo li cov tshuaj hnyav xws li sulfuric acid lossis chlorinated cov kuab tshuaj, hydrogen peroxide yog qhov zoo thiab decomposes rau hauv dej thiab oxygen nyob rau hauv cov mob me.Cov yam ntxwv zoo ib puag ncig no ua rau nws tsim nyog rau kev ua haujlwm cellulose kom ruaj khov thiab kho cov khib nyiab.
Cov xwm txheej me me: Hydrogen peroxide-mediated cellulose dissolution tuaj yeem ua tau nyob rau hauv cov mob me me ntawm qhov kub thiab txias, txo kev siv hluav taws xob thiab cov nqi ua haujlwm piv rau cov kub kub acid hydrolysis lossis ionic kua kho.
Selective Oxidation: Lub oxidative cleavage ntawm glycosidic bonds los ntawm hydrogen peroxide tuaj yeem tswj tau qee qhov, tso cai rau kev xaiv hloov pauv ntawm cellulose chains thiab tsim cov khoom tsim los ntawm cov khoom tshwj xeeb.
Daim ntawv thov ntau yam: Cov soluble cellulose derivatives tau los ntawm hydrogen peroxide-mediated dissolution muaj peev xwm siv nyob rau hauv ntau yam teb, xws li biofuel ntau lawm, cov khoom siv, biomedical devices, thiab dej khib nyiab.
Cov kev sib tw thiab cov kev taw qhia yav tom ntej:
Txawm hais tias nws cov cwj pwm zoo, hydrogen peroxide-mediated cellulose dissolution ntsib ntau qhov kev sib tw thiab thaj chaw rau kev txhim kho:
Selectivity thiab Yield: Ua tiav cov txiaj ntsig siab ntawm soluble cellulose derivatives nrog cov kev tawm tsam tsawg kawg nkaus tseem yog qhov nyuaj, tshwj xeeb tshaj yog rau cov khoom siv biomass complex uas muaj lignin thiab hemicellulose.
Scale-Up and Process Integration: Scaling up hydrogen peroxide-based cellulose dissolution processes to industrial theem yuav tsum tau ua tib zoo xav txog kev tsim reactor, hnyav rov qab, thiab cov kauj ruam hauv nqes los ua kom muaj kev lag luam thiab kev ruaj ntseg ib puag ncig.
Kev Txhim Kho Catalyst: Kev tsim cov catalysts zoo rau kev ua kom hydrogen peroxide thiab cellulose oxidation yog qhov tseem ceeb rau kev txhim kho cov tshuaj tiv thaiv thiab kev xaiv thaum txo qis catalyst loading thiab tsim los ntawm cov khoom.
Valorization ntawm By-Products: Cov tswv yim rau valorizing cov by-products generated thaum lub sij hawm hydrogen peroxide-mediated cellulose dissolution, xws li carboxylic acids los yog oligomeric qab zib, yuav ntxiv txhim khu lub zuag qhia tag nrho sustainability thiab economic ntsoog ntawm cov txheej txheem.
Hydrogen peroxide tuav cov lus cog tseg tseem ceeb raws li cov kuab tshuaj ntsuab thiab muaj txiaj ntsig zoo rau kev tshem tawm cov cellulose, muab qhov zoo xws li kev sib raug zoo ib puag ncig, cov tshuaj tiv thaiv me me, thiab xaiv oxidation.Txawm hais tias muaj kev sib tw tsis tu ncua, kev tshawb fawb txuas ntxiv txhawm rau txhawm rau txheeb xyuas cov txheej txheem hauv qab, txhim kho cov tshuaj tiv thaiv tsis zoo, thiab tshawb nrhiav cov ntawv thov tshiab yuav txhim kho qhov ua tau thiab kev ruaj khov ntawm cov txheej txheem hydrogen peroxide rau cellulose valorization.
Lub sij hawm xa tuaj: Plaub Hlis-10-2024