Membrane sib cais tshuab, nrog nws qhov zoo ntawm kev ua haujlwm siab, txuag hluav taws xob, thiab kev ua haujlwm yooj yim, yog siv dav hauv kev kho dej, kev ua zaub mov, biomedicine, thiab tshuaj lom neeg kev lag luam. Txawm li cas los xij, thaum lub sijhawm ua haujlwm ntev -, daim nyias nyias fouling tseem yog qhov teeb meem tseem ceeb txwv nws txoj kev ua haujlwm thiab kev ua neej. Tshwj xeeb tshaj yog rau cov porous membranes xws li ultrafiltration, nanofiltration, thiab thim rov qab osmosis, fouling tsis tsuas yog ua rau txo qis flux thiab nce zog noj tab sis kuj tuaj yeem ua rau kev puas tsuaj rau daim nyias nyias. Yog li, dab tsi yam cuam tshuam rau daim nyias nyias fouling? Los ntawm cov khoom siv rau kev ua haujlwm, tsab xov xwm no tau tshuaj xyuas 6 yam tseem ceeb cuam tshuam rau daim nyias nyias fouling thiab, ua ke nrog cov qauv theoretical classic, coj koj kom nkag siab lub hauv paus ua rau fouling los ntawm kev xav txog kev siv tshuab.
I. Particle lossis Solute Size thiab Morphology
Thaum cov khoom los yog colloids mus rau ntawm daim nyias nyias, lawv raug rau ntau lub zog, suav nrog van der Waals rog, electrostatic rog, thiab cov kua dej shear rog. Yog hais tias cov particle loj me me los yog spherical, lawv muaj feem ntau yuav tsim ib txheej densely ntim rau ntawm daim nyias nyias, ua rau blockage thiab irreversible fouling. Conversely, fibrous los yog dendritic hais yog ntau cuam tshuam los ntawm kev khiav hauj lwm cuam tshuam, ua rau kuj tsis muaj zog adsorption.
Tshwj xeeb tshaj yog thaum cov khoom raug them, lub zog ionic, kev faib tawm, thiab daim nyias nyias muaj peev xwm hauv cov tshuaj cuam tshuam rau qhov fouling nyiam. Piv txwv li, cov khoom zoo colloids feem ntau yuav adsorb mus rau qhov tsis zoo ntawm daim nyias nyias, yog li tsim ib "neutralized adsorption txheej." Tsis tas li ntawd, aggregated colloids lossis polymers tsis ruaj khov hauv cov kua dej thiab tuaj yeem sib sau ua ke thiab tso rau hauv lub zog shear, ua kom cov membrane fouling.
II. Solute-Kev sib cuam tshuam ntawm Membrane
Kev sib cuam tshuam quab yuam ntawm cov kua nplaum thiab cov khoom siv membrane yog ib qho tseem ceeb tshaj plaws cuam tshuam rau daim nyias nyias fouling. Raws li cov txheej txheem, cov no tuaj yeem muab faib ua electrostatic rog, van der Waals rog, hydrogen bonding, thiab steric hindrance.
1. Cov Hluav Taws Xob Hluav Taws Xob
Yog tias cov khoom siv hauv daim nyias nyias muaj cov pab pawg them nyiaj (xws li carboxyl lossis amine pawg), electrostatic adsorption yuav tshwm sim thaum cov kua dej hauv cov tshuaj nqa cov nqi sib txawv, txhawb kev tsim fouling txheej. Hloov pauv, yog tias daim nyias nyias thiab cov kua nplaum nqa tib lub nqi, electrostatic repulsion pab txo fouling.
2. Van der Waals Forces
Qhov no yog ib tug universal intermolecular attraction, characterized los ntawm lub Hamaker tas li. Lub van der Waals rog ntawm cov kua nplaum thiab daim nyias nyias tuaj yeem suav nrog cov qauv hauv qab no:
Qhov twg H11, H22, thiab H33 yog Hamaker tas li ntawm cov khoom siv membrane, solute, thiab daws, feem.
Qhov me me ntawm H213 tus nqi, qhov tsis muaj zog qhov kev nyiam ntawm daim nyias nyias thiab cov kuab tshuaj, thiab qhov qis dua qhov nyiam foul. Qhov no txhais tau hais tias kev xaiv cov ntaub ntawv membrane yuav tsum tsis txhob tsim kom muaj zog molecular attraction nrog cov kua. Piv txwv li, hauv kev kho dej, cov ntaub ntawv membrane uas muaj zog hydrophilicity thiab tsis tshua muaj zog saum npoo yog feem ntau tiv taus fouling.
3. Hydrogen Bonding Hydrogen bonds yog ib hom high - zog tshuaj daim ntawv cog lus, tshwj xeeb tshaj yog tseem ceeb rau polar solutes. Thaum cov organic tebchaw uas muaj cov pab pawg ua haujlwm xws li hydroxyl thiab carboxyl pawg tuaj rau hauv kev sib cuag nrog daim nyias nyias, lawv tuaj yeem tsim hydrogen- txheej txheej, ua rau fouling hnyav. Ntuj organic molecules (NOMs) los yog biomolecules tshwj xeeb tshaj yog nquag tsim "organic fouling txheej" ntawm daim nyias nyias los ntawm hydrogen bonding.
4. Steric Hinderation Rau polymers los yog biomolecules nrog ntev molecular chains, txav nyob rau hauv daim nyias nyias pores los yog nyob rau saum npoo yog spatially txwv. Thaum muaj zog steric hindrance nyob rau hauv lub system, cov pa phem yog nyuaj rau mus rau ntawm daim nyias nyias, yog li txo cov kab mob mus rau qee yam.
III. Membrane Structure thiab Properties
Cov yam ntxwv ntawm cov txheej txheem ntawm daim nyias nyias ncaj qha txiav txim siab nws cov kev ua haujlwm antifouling. Microscopically, tsis xws li pore loj tis, nto roughness, tus yam ntxwv nqi, thiab hydrophilicity tag nrho cov cuam tshuam cov kab mob.
1. Pore Loj thiab Pore Structure
Ultrafiltration los yog nanofiltration membranes nrog me pore qhov ntau thiab tsawg yog feem ntau yuav txo tau flux vim particle blockage. Yog hais tias qhov pore loj faib tsis sib npaug los yog cov tawv nqaij muaj teeb meem, kev sib kis yuav hnyav dua. Qhov no piav qhia vim li cas qee lub tuam txhab Asmeskas lub tuam txhab ultrafiltration membrane, thawj lub npe muaj qhov pore loj ntawm 0.02 micrometers, muaj qhov pore loj tsis sib xws; nyob rau hauv xyoo tas los no, lawv tau tshaj tawm XP series ultrafiltration membranes nrog ntau qhov sib txawv pore loj.
2. Nto Roughness
Rough membrane nto muaj ntau micropores thiab grooves, yooj yim tsim ib qho chaw nyob ruaj khov, ua rau muaj kuab paug paug.
3. Hydrophilicity
Hydrophilic membranes feem ntau muaj qis zog saum npoo thiab txheej nyias nyias, tso cai rau cov dej molecules yooj yim tsim "hydration film" ntawm daim nyias nyias, yog li inhibiting cov organic teeb meem deposition. Hydrophilicity feem ntau yog nyob ntawm daim nyias nyias qhov kev sib cuag lub kaum sab xis. Tus nqi no feem ntau yog muab rau hauv daim ntawv qhia daim nyias nyias rau cov khoom tuaj txawv teb chaws, uas cov neeg nyeem tuaj yeem xa mus rau thaum yuav daim nyias nyias. Txawm li cas los xij, nws tsis tshua muaj nyob rau hauv phau ntawv qhia rau domestically tsim membranes.
4. Cov yam ntxwv them nqi
Negatively charged daim nyias nyias nto tiv tsis zoo nqi colloids los yog hais, txo fouling. Txawm li cas los xij, thaum cov tshuaj muaj cations, them nyiaj nruab nrab tuaj yeem tshwm sim, ua rau kev txhim kho adsorption. Qhov no yog ib qho laj thawj vim li cas daim nyias nyias fouling sai hauv siab - dej qab ntsev.
IV. Influence of Solution Characteristics Cov khoom siv tshuaj ntawm cov tshuaj muaj kev cuam tshuam loj heev rau daim nyias nyias fouling. Cov no feem ntau suav nrog: (1) pH hloov pauv tus nqi ntawm cov kuab tshuaj thiab daim nyias nyias, yog li cuam tshuam rau kev cuam tshuam electrostatic; (2) Lub zog ionic siab tuaj yeem ua rau ob txheej txheej, ua kom tsis muaj zog electrostatic repulsion thiab ua kom muaj kuab paug yooj yim rau adsorb, xws li hauv siab - dej qab ntsev; (3) Qhov kub thiab txias txo qhov kev daws viscosity, nce flux nyob rau hauv lub sij hawm luv luv, tab sis kuj accelerates kev sib cuam tshuam ntawm cov organic teeb meem thiab daim nyias nyias, muaj feem cuam tshuam fouling nyob rau hauv lub sij hawm ntev; (4) Lub complexity ntawm coexisting system ntawm cov organic teeb meem, colloids, thiab hlau ions nyob rau hauv cov tshuaj yuav ua rau complex fouling.
V. Lub cev muaj zog ntawm Membranes
Lub cev muaj zog ntawm daim nyias nyias muaj xws li nto roughness, pore loj faib, porosity, thiab nto nqi. Cov npoo ntawm daim nyias nyias yog tsis tshua muaj fouling; uniform pore loj faib ua rau cov permeate ruaj khov thiab qeeb fouling txheej tsim. Tsis tas li ntawd, yog tias cov khoom siv ntawm daim nyias nyias yog qhov tsis zoo, nws tuaj yeem tsim qhov ruaj khov electrostatic barrier hauv dej, tiv thaiv qhov tsis zoo ntawm cov kuab tshuaj los ntawm kev txav mus los; thaum tus nqi yog ib nrab neutralized los yog daim nyias nyias muaj cov cheeb tsam hydrophobic, nws yog feem ntau adsorb organic teeb meem.
Yog li ntawd, optimizing lub membrane qauv los ntawm cov ntaub ntawv science foundations yog ib qho tseem ceeb cov lus qhia rau suppressing fouling. Piv txwv li, siv hydrophilic polyamide puas daim nyias nyias los yog qhia cov pawg polar xws li hydroxyl thiab carboxyl pawg ntawm daim nyias nyias tuaj yeem txhim kho cov khoom tiv thaiv fouling.
VI. Kev khiav hauj lwm Parameter
Kev ua haujlwm tsis ua haujlwm ntawm cov txheej txheem membrane ua lub luag haujlwm txiav txim siab hauv kev tsim fouling. Cov tsis tseem ceeb muaj xws li transmembrane siab sib txawv (TMP), transmembrane txaus tshaj tawm (CFV), thiab flux (J).
1. Flux thiab Critical Flux
Thaum cov flux tshaj ib qho kev txwv, qhov fouling tus nqi nce sharply. Field et al. thawj zaug tau tshaj tawm lub tswvyim ntawm "kev cuam tshuam tseem ceeb" hauv xyoo 1995 los piav txog qhov tseem ceeb ntawm fouling.
Thaum cov kev khiav hauj lwm flux qis dua qhov tseem ceeb flux Jc, ib txheej irreversible fouling yuav tsis tsim rau ntawm daim nyias nyias; Thaum cov flux tshaj Jc, cov kab mob kis tau sai sai, thiab kev tiv thaiv nce ntxiv raws sijhawm.
Thaum lub sijhawm ua haujlwm ntev - lub sijhawm ua haujlwm, lub kaw lus yuav tsum nyob ruaj khov nyob rau hauv qhov chaw qis dua qhov tseem ceeb los ntawm kev tswj cov dej ntws ntawm cov dej ntws thiab qhov sib txawv ntawm qhov sib txawv ntawm transmembrane.
2. Shear Force thiab kua muaj nuj nqi
Siab shear rog pab tshem tawm cov fouling txheej ntawm daim nyias nyias, tab sis ntau shear quab yuam yuav ua rau cov membrane puas los yog ua kom lub zog noj. Yog li ntawd, xaiv tus nqi txaus thiab kev pom zoo (xws li tus ntoo khaub lig-flow filtration) yog qhov tseem ceeb.
3. Kub thiab ua haujlwm siab
Qhov kub nce ntxiv txo cov kua viscosity thiab nce permeation tus nqi, tab sis nws kuj txhim kho cov kua qaub adsorption. Kev khiav hauj lwm siab dhau heev tuaj yeem ua rau cov txheej txheem fouling, tsim kom muaj cov txheej txheem denser.
Cov ntsiab lus
Membrane fouling yog txheej txheem nyuaj uas muaj ntau yam ua ke, cuam tshuam los ntawm ob qho tib si khoom thiab kev ua haujlwm. Los ntawm kev xav txog kev siv tshuab, qhov loj me me, tus nqi saum npoo, kev sib cuam tshuam molecular rog, cov khoom siv ntawm cov khoom siv membrane, thiab cov kua dej dynamics sib sau ua ke txiav txim siab tsim thiab hloov pauv ntawm fouling. Cov lus qhia yav tom ntej rau kev tswj cov membrane fouling yuav tsom mus ntxiv rau: kev hloov kho saum npoo thiab kev ua haujlwm ntawm cov khoom siv membrane, kev tswj xyuas kev ua haujlwm zoo thiab kev tswj xyuas qhov tseem ceeb, kev tswj xyuas kev daws teeb meem, thiab kev ua kom zoo ntawm lub zog interfacial. Tsuas yog los ntawm kev pib ntawm microscopic kev sib cuam tshuam thiab kev nkag siab zoo ntawm fouling mechanism tuaj yeem ua tiav kev ua haujlwm siab thiab kev ruaj khov hauv cov txheej txheem membrane sib cais hauv kev ua haujlwm engineering.