Txais tos rau peb lub vev xaib kom tau cov ntaub ntawv hais txog khoom thiab kev sab laj.
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Txoj kev ua kom lub cev thiab tshuaj lom neeg ua haujlwm
Txoj kev ua kom lub cev thiab tshuaj lom neeg ua haujlwm yog hais txog txoj kev npaj cov khoom siv uas muaj qhov ntxeem tau los ntawm kev sib txuas ob txoj kev ua kom lub cev ua haujlwm saum toj no. Feem ntau, kev ua kom lub cev ua haujlwm yog ua ua ntej, thiab tom qab ntawd kev ua kom lub cev ua haujlwm. Ua ntej, muab cellulose tso rau hauv 68% ~ 85% H3PO4 kua ntawm 85 ℃ rau 2 teev, tom qab ntawd carbonized nws hauv lub cub tawg rau 4 teev, thiab tom qab ntawd ua kom nws ua haujlwm nrog CO2. Qhov chaw tshwj xeeb ntawm cov pa roj carbon ua haujlwm tau txais yog siab txog 3700m2 · g-1. Sim siv cov fiber sisal ua cov khoom siv raw, thiab ua kom cov pa roj carbon ua haujlwm (ACF) tau txais los ntawm kev ua kom H3PO4 ua haujlwm ib zaug, ua kom sov rau 830 ℃ hauv qab kev tiv thaiv N2, thiab tom qab ntawd siv cov pa dej ua tus ua kom lub cev ua haujlwm thib ob. Qhov chaw tshwj xeeb ntawm ACF tau txais tom qab 60 feeb ntawm kev ua kom lub cev ua haujlwm tau zoo dua.
Kev piav qhia txog kev ua haujlwm ntawm cov qauv pore ntawm cov activatedcov pa roj carbon
Cov txheej txheem piav qhia txog kev ua haujlwm ntawm cov pa roj carbon uas siv ntau thiab cov lus qhia siv tau qhia nyob rau hauv Rooj 2. Cov yam ntxwv ntawm cov qauv pore ntawm cov khoom siv tuaj yeem sim los ntawm ob qho: kev tshuaj xyuas cov ntaub ntawv thiab kev tshuaj xyuas duab.
Kev tshawb fawb txog kev nce qib ntawm cov txheej txheem kho kom zoo dua ntawm cov pa roj carbon uas ua kom muaj zog
Txawm hais tias cov pa roj carbon activated muaj cov qhov ntau thiab thaj chaw loj heev, nws muaj kev ua tau zoo heev hauv ntau qhov chaw. Txawm li cas los xij, vim nws cov khoom siv raw xaiv dav thiab cov xwm txheej npaj ua tiav, cov khoom tiav feem ntau muaj qhov tsis zoo ntawm cov qauv qhov tsis sib xws, thaj chaw sib txawv, qhov loj me ntawm qhov tsis sib xws, thiab cov khoom siv tshuaj lom neeg tsawg. Yog li ntawd, muaj qhov tsis zoo xws li cov tshuaj ntau thiab kev hloov pauv nqaim hauv cov txheej txheem thov, uas tsis tuaj yeem ua tau raws li qhov xav tau ntawm kev ua lag luam. Yog li ntawd, nws yog qhov tseem ceeb heev rau kev ua kom zoo dua thiab tswj cov qauv thiab txhim kho nws cov kev ua tau zoo siv. Cov txheej txheem siv feem ntau rau kev ua kom zoo dua thiab tswj cov qauv qhov muaj xws li kev tswj tshuaj lom neeg, kev sib xyaw polymer, thiab kev tswj hwm catalytic.
Kev tswj hwm tshuaj lom neeg
Kev siv tshuab tswj tshuaj lom neeg yog hais txog cov txheej txheem ntawm kev ua kom muaj zog thib ob (kev hloov kho) ntawm cov khoom siv porous tau txais tom qab kev ua kom muaj zog nrog cov tshuaj reagents, ua rau cov qhov qub puas tsuaj, nthuav cov micropores, lossis tsim cov micropores tshiab ntxiv kom nce thaj chaw tshwj xeeb thiab cov qauv pore ntawm cov khoom. Feem ntau hais lus, cov khoom tiav ntawm ib qho kev ua kom muaj zog feem ntau raug muab tso rau hauv 0.5 ~ 4 zaug ntawm cov tshuaj lom neeg los tswj cov qauv pore thiab nce thaj chaw tshwj xeeb. Txhua yam kua qaub thiab alkali daws tuaj yeem siv ua reagents rau kev ua kom muaj zog thib ob.
Kev hloov kho tshuab oxidation ntawm cov kua qaub
Kev hloov kho qhov chaw oxidation ntawm cov kua qaub yog ib txoj kev tswj hwm uas siv ntau. Thaum kub txaus, cov tshuaj oxidant ntawm cov kua qaub tuaj yeem ua rau cov qhov hauv cov pa roj carbon ua kom nplua nuj, txhim kho nws qhov loj me, thiab tshem cov qhov uas raug thaiv. Tam sim no, kev tshawb fawb hauv tsev thiab txawv teb chaws feem ntau tsom mus rau kev hloov kho cov kua qaub inorganic. HN03 yog cov tshuaj oxidant uas siv ntau, thiab ntau tus kws tshawb fawb siv HN03 los hloov kho cov pa roj carbon ua kom muaj zog. Tong Li et al. [28] pom tias HN03 tuaj yeem ua rau cov pa oxygen thiab cov nitrogen ua haujlwm ntau ntxiv rau ntawm cov pa roj carbon ua kom muaj zog thiab txhim kho cov nyhuv adsorption ntawm mercury.
Kev hloov kho cov pa roj carbon uas ua haujlwm nrog HN03, tom qab kev hloov kho, thaj chaw tshwj xeeb ntawm cov pa roj carbon uas ua haujlwm tau txo qis los ntawm 652m2 · g-1 mus rau 241m2 · g-1, qhov nruab nrab ntawm qhov loj me nce ntxiv los ntawm 1.27nm mus rau 1.641nm, thiab lub peev xwm adsorption ntawm benzophenone hauv roj av simulated nce ntxiv 33.7%. Kev hloov kho cov pa roj carbon uas ua haujlwm los ntawm ntoo nrog 10% thiab 70% ntim concentration ntawm HN03, raws li. Cov txiaj ntsig qhia tau tias thaj chaw tshwj xeeb ntawm cov pa roj carbon uas ua haujlwm tau hloov kho nrog 10% HN03 nce ntxiv los ntawm 925.45m2 · g-1 mus rau 960.52m2 · g-1; tom qab kev hloov kho nrog 70% HN03, thaj chaw tshwj xeeb txo qis mus rau 935.89m2 · g-1. Cov nqi tshem tawm ntawm Cu2 + los ntawm cov pa roj carbon uas ua haujlwm tau hloov kho nrog ob qhov concentration ntawm HN03 yog siab dua 70% thiab 90%, raws li.
Rau cov pa roj carbon uas siv rau hauv qhov chaw nqus dej, qhov cuam tshuam ntawm kev nqus dej tsis yog nyob ntawm qhov qauv ntawm qhov pore xwb tab sis kuj nyob ntawm cov khoom siv tshuaj lom neeg ntawm qhov chaw nqus dej. Cov qauv ntawm qhov pore txiav txim siab qhov chaw tshwj xeeb thiab lub peev xwm nqus dej ntawm cov pa roj carbon uas ua haujlwm, thaum cov khoom siv tshuaj lom neeg ntawm qhov chaw cuam tshuam rau kev sib cuam tshuam ntawm cov pa roj carbon uas ua haujlwm thiab cov adsorbate. Thaum kawg nws tau pom tias kev hloov kho acid ntawm cov pa roj carbon uas ua haujlwm tsis tsuas yog kho qhov qauv ntawm qhov pore hauv cov pa roj carbon uas ua haujlwm thiab tshem tawm cov qhov pore uas raug thaiv, tab sis kuj ua rau cov ntsiab lus ntawm cov pab pawg acidic ntawm qhov chaw ntawm cov khoom siv thiab txhim kho qhov polarity thiab hydrophilicity ntawm qhov chaw. Lub peev xwm nqus dej ntawm EDTA los ntawm cov pa roj carbon uas ua haujlwm hloov kho los ntawm HCI nce 49.5% piv rau qhov ua ntej hloov kho, uas zoo dua li ntawm HNO3 hloov kho.
Cov pa roj carbon ua haujlwm uas tau hloov kho nrog HNO3 thiab H2O2 feem! Cov cheeb tsam tshwj xeeb tom qab hloov kho yog 91.3% thiab 80.8% ntawm cov ua ntej hloov kho, feem. Cov pab pawg ua haujlwm uas muaj cov pa oxygen tshiab xws li carboxyl, carbonyl thiab phenol tau ntxiv rau saum npoo. Lub peev xwm nqus ntawm nitrobenzene los ntawm kev hloov kho HNO3 yog qhov zoo tshaj plaws, uas yog 3.3 npaug ntawm ua ntej hloov kho. Nws pom tias qhov nce ntawm cov ntsiab lus ntawm cov pab pawg ua haujlwm uas muaj cov pa oxygen hauv cov pa roj carbon ua haujlwm tom qab hloov kho acid ua rau muaj kev nce ntxiv ntawm cov ntsiab lus ua haujlwm ntawm qhov chaw, uas muaj kev cuam tshuam ncaj qha rau kev txhim kho lub peev xwm nqus ntawm lub hom phiaj adsorbate.
Piv nrog cov inorganic acids, muaj ob peb daim ntawv qhia txog kev hloov pauv organic acid ntawm cov pa roj carbon activated. Piv cov teebmeem ntawm kev hloov pauv organic acid ntawm cov qauv pore ntawm cov pa roj carbon activated thiab kev nqus ntawm methanol. Tom qab kev hloov pauv, thaj chaw tshwj xeeb thiab tag nrho cov pore ntim ntawm cov pa roj carbon activated txo qis. Qhov muaj zog ntawm acidity, qhov ntau dua qhov txo qis. Tom qab kev hloov pauv nrog oxalic acid, tartaric acid thiab citric acid, thaj chaw tshwj xeeb ntawm cov pa roj carbon activated txo qis los ntawm 898.59m2 · g-1 mus rau 788.03m2 · g-1, 685.16m2 · g-1 thiab 622.98m2 · g-1 feem. Txawm li cas los xij, qhov microporosity ntawm cov pa roj carbon activated nce tom qab kev hloov pauv. Qhov microporosity ntawm cov pa roj carbon activated hloov kho nrog citric acid nce los ntawm 75.9% mus rau 81.5%.
Kev hloov pauv ntawm oxalic acid thiab tartaric acid yog qhov zoo rau kev nqus ntawm methanol, thaum citric acid muaj cov nyhuv inhibitory. Txawm li cas los xij, J.Paul Chen et al. [35] pom tias cov pa roj carbon uas tau hloov kho nrog citric acid tuaj yeem txhim kho kev nqus ntawm cov ions tooj liab. Lin Tang et al. [36] hloov kho cov pa roj carbon uas tau hloov kho nrog formic acid, oxalic acid thiab aminosulfonic acid. Tom qab kev hloov kho, thaj chaw tshwj xeeb thiab qhov ntim ntawm qhov hws tau txo qis. Cov pab pawg ua haujlwm uas muaj oxygen xws li 0-HC-0, C-0 thiab S = 0 tau tsim rau ntawm qhov chaw ntawm cov khoom tiav, thiab cov channel etched tsis sib xws thiab cov siv lead dawb tau tshwm sim. Lub peev xwm nqus dej sib npaug ntawm acetone thiab isopropanol kuj nce ntxiv ntau.
Kev siv tshuab hloov kho cov kua alkaline
Qee cov kws tshawb fawb kuj siv cov kua alkaline los ua qhov kev ua haujlwm thib ob ntawm cov pa roj carbon activated. Impregnate cov pa roj carbon activated ua hauv tsev nrog cov kua Na0H ntawm ntau qhov sib txawv kom tswj tau cov qauv pore. Cov txiaj ntsig tau qhia tias qhov concentration alkali qis dua yog qhov ua rau pore nce thiab nthuav dav. Qhov zoo tshaj plaws tau ua tiav thaum qhov concentration ntawm cov pa roj carbon activated yog 20%. Cov pa roj carbon activated muaj thaj chaw tshwj xeeb tshaj plaws (681m2 · g-1) thiab qhov ntim ntawm pore (0.5916cm3 · g-1). Thaum qhov concentration ntawm Na0H ntau tshaj 20%, cov qauv pore ntawm cov pa roj carbon activated raug rhuav tshem thiab cov qauv pore pib txo qis. Qhov no yog vim tias qhov concentration ntawm Na0H kua yuav ua rau cov pob txha carbon xeb thiab ntau qhov pores yuav tawg.
Npaj cov pa roj carbon ua haujlwm siab los ntawm kev sib xyaw polymer. Cov khoom ua ntej yog furfural resin thiab furfuryl cawv, thiab ethylene glycol yog tus neeg sawv cev tsim cov qhov. Cov qauv qhov tau tswj los ntawm kev kho cov ntsiab lus ntawm peb cov polymers, thiab cov khoom siv porous nrog qhov loj me ntawm 0.008 thiab 5 μm tau txais. Qee cov kws tshawb fawb tau ua pov thawj tias zaj duab xis polyurethane-imide (PUI) tuaj yeem carbonized kom tau txais zaj duab xis carbon, thiab cov qauv qhov tuaj yeem tswj tau los ntawm kev hloov cov qauv molecular ntawm polyurethane (PU) prepolymer [41]. Thaum PUI raug cua sov rau 200 ° C, PU thiab polyimide (PI) yuav tsim. Thaum qhov kub kho cua sov nce mus txog 400 ° C, PU pyrolysis tsim cov roj, ua rau muaj cov qauv qhov ntawm zaj duab xis PI. Tom qab carbonization, tau txais zaj duab xis carbon. Tsis tas li ntawd, txoj kev sib xyaw polymer kuj tseem tuaj yeem txhim kho qee yam khoom siv lub cev thiab cov khoom siv kho tshuab ntawm cov khoom siv rau qee qhov.
Kev siv tshuab tswj kev ua kom muaj catalytic
Cov txheej txheem tswj kev ua kom muaj catalytic yog qhov tseeb ua ke ntawm txoj kev ua kom muaj tshuaj lom neeg thiab txoj kev ua kom muaj roj kub siab. Feem ntau, cov tshuaj lom neeg raug ntxiv rau cov khoom siv raw ua cov catalysts, thiab cov catalysts raug siv los pab cov txheej txheem carbonization lossis kev ua kom muaj zog kom tau txais cov khoom siv carbon porous. Feem ntau hais lus, cov hlau feem ntau muaj cov teebmeem catalytic, tab sis cov teebmeem catalytic sib txawv.
Qhov tseeb, feem ntau tsis muaj ciam teb pom tseeb ntawm kev tswj hwm kev ua kom muaj tshuaj lom neeg thiab kev tswj hwm kev ua kom muaj catalytic ntawm cov ntaub ntawv porous. Qhov no yog vim tias ob txoj kev ntxiv cov tshuaj reagents thaum lub sijhawm carbonization thiab kev ua kom muaj zog. Lub luag haujlwm tshwj xeeb ntawm cov tshuaj reagents no txiav txim siab seb txoj kev no puas yog rau pawg ntawm catalytic activation.
Cov qauv ntawm cov khoom siv carbon porous nws tus kheej, cov khoom siv lub cev thiab tshuaj lom neeg ntawm cov catalyst, cov xwm txheej catalytic reaction thiab cov txheej txheem catalyst loading tuaj yeem muaj ntau qib sib txawv ntawm kev cuam tshuam rau cov nyhuv tswj. Siv cov thee bituminous ua cov khoom siv raw, Mn (N03) 2 thiab Cu (N03) 2 ua cov catalysts tuaj yeem npaj cov khoom siv porous uas muaj cov hlau oxides. Tus nqi tsim nyog ntawm cov hlau oxides tuaj yeem txhim kho qhov porosity thiab pore ntim, tab sis cov teebmeem catalytic ntawm cov hlau sib txawv yog qhov sib txawv me ntsis. Cu (N03) 2 tuaj yeem txhawb kev txhim kho ntawm cov qhov hws hauv qhov ntau ntawm 1.5 ~ 2.0 nm. Tsis tas li ntawd, cov hlau oxides thiab cov ntsev inorganic uas muaj nyob rau hauv cov khoom siv raw tshauv kuj tseem yuav ua lub luag haujlwm catalytic hauv cov txheej txheem ua kom muaj zog. Xie Qiang et al. [42] ntseeg tias qhov kev ua kom muaj zog catalytic ntawm cov ntsiab lus xws li calcium thiab hlau hauv cov khoom inorganic tuaj yeem txhawb kev txhim kho ntawm cov qhov hws. Thaum cov ntsiab lus ntawm ob lub ntsiab lus no siab dhau, qhov feem pua ntawm cov qhov hws nruab nrab thiab loj hauv cov khoom nce ntxiv ntau.
Xaus lus
Txawm hais tias cov pa roj carbon activated, ua cov khoom siv carbon ntsuab uas siv ntau tshaj plaws, tau ua lub luag haujlwm tseem ceeb hauv kev lag luam thiab lub neej, nws tseem muaj peev xwm zoo rau kev txhim kho hauv kev nthuav dav ntawm cov khoom siv raw, txo tus nqi, txhim kho zoo, txhim kho lub zog, txuas ntxiv lub neej thiab txhim kho lub zog. Nrhiav cov khoom siv raw carbon activated zoo thiab pheej yig, tsim cov thev naus laus zis tsim cov pa roj carbon activated huv thiab ua haujlwm tau zoo, thiab ua kom zoo thiab tswj cov qauv pore ntawm cov pa roj carbon activated raws li cov teb sib txawv yuav yog qhov kev taw qhia tseem ceeb rau kev txhim kho qhov zoo ntawm cov khoom siv carbon activated thiab txhawb kev txhim kho zoo ntawm kev lag luam carbon activated.
Lub sijhawm tshaj tawm: Lub Yim Hli-27-2024