Tom qab daim nyias nyias fouling, ntxuav yog tsim nyog los kho nws cov kev ua tau zoo. Thaum cov txheej txheem ntxuav tawm los ntawm cov chaw tsim khoom sib txawv sib txawv, lub hauv paus ntsiab lus tseem ceeb yog tib yam: tshem tawm cov kab mob ntawm daim nyias nyias thiab qhov hws los ntawm kev siv lub cev, tshuaj, thiab tshuaj lom neeg, yog li rov kho cov membrane flux thiab selectivity. Tsab ntawv xov xwm no yuav qhia txog cov txheej txheem tseem ceeb thiab cov cim qhia txog kev ua haujlwm ntawm daim nyias nyias rau cov kws kho dej.
I. Txheej txheem cej luam ntawm Membrane Cleaning Methods
Cov txheej txheem tu cov ntaub nplaum feem ntau tuaj yeem muab faib ua peb pawg: kev tu lub cev, tshuaj ntxuav, thiab kev tu tsiaj. Txhua tus muaj nws tus yam ntxwv thiab tuaj yeem siv tus kheej lossis ua ke.
1. Kev ntxuav lub cev
Kev tu lub cev feem ntau suav nrog kev rov qab ntxuav, hydraulic flushing, ultrasonic tu, thiab tshuab ntxhua khaub ncaws. Cov txheej txheem no tso siab rau kev siv tshuab lossis hydraulic ua kom tshem tawm cov kab mob uas ua rau lub membrane nto. Lawv tsis yog - cov txheej txheem tshuaj, kev ua haujlwm yooj yim, tsis tshua muaj nqi, thiab ua rau muaj kev puas tsuaj tsawg rau cov khoom siv membrane, feem ntau ua rau lawv nyiam txoj kev tu. Cov kev tu lub cev feem ntau muaj xws li rov qab ntxuav, qis - siab lossis siab - siab ntws tawm, thiab qee qhov kev tu lub cev tsawg dua, xws li kev tu ultrasonic thiab hluav taws xob tu.
Backwashing yuav tsum siv lub siab rov qab los yuam kom cov dej huv rau hauv daim nyias nyias pores los ntawm sab permeate, tshem tawm cov kab mob uas adhering rau daim nyias nyias thiab hauv qhov pores. Txoj kev no yog tshwj xeeb tshaj yog zoo rau hollow fiber membranes, xws li ultrafiltration los yog hollow fiber nanofiltration membranes.
Tsawg- siab lossis siab - lub siab ntws tawm siv cov dej ntws tawm sab nraud los cuam tshuam rau daim nyias nyias, tshem tawm cov khoom xoob.
Ultrasonic nthwv dej tsim cavitation hauv cov kua; cov kwj deg microjet tsim thaum npuas tawg zoo cuam tshuam rau daim nyias nyias, loosening thiab tshem tawm cov fouling txheej. Txoj kev no yog tsim rau kev tshem tawm offline ntawm ruaj khov nrog cov organic lossis colloidal fouling.
Kev ntxuav hluav taws xob siv hluav taws xob hauv hluav taws xob rau ob qho kawg ntawm daim nyias nyias, siv electroosmosis thiab electrochemical tshuaj tiv thaiv kom tshem tawm cov kab mob. Qhov no yog ib tug tshiab membrane regeneration technology.
Kev tu lub cev yog yooj yim rau kev khiav lag luam, pheej yig, thiab ib puag ncig tus phooj ywg; Txawm li cas los xij, nws txoj kev ua tau zoo yog txwv rau cov nplaum nplaum organic thiab cov txheej txheem inorganic. Yog li ntawd, nws yog feem ntau siv ua ke nrog tshuaj ntxuav.
2. Chemical Cleaning Kev tu tshuaj yog tsim nyog thaum kev ntxuav lub cev tsis zoo. Kev ntxuav tshuaj yog txheej txheem uas siv cov tshuaj tua kab mob kom yaj, ua kom yooj yim, oxidize, lossis saponify cov kab mob hauv thiab sab nraud ntawm daim nyias nyias pores, ua rau cov txheej txheem hloov pauv lossis hloov mus rau hauv cov tshuaj soluble, yog li rov ua haujlwm ntawm daim nyias nyias. Raws li cov khoom siv ntawm cov neeg ua haujlwm siv, tshuaj ntxuav tes tuaj yeem muab faib ua pawg hauv qab no:
(1) Acid Ntxuav
Acid ntxuav feem ntau yog siv los tshem tawm cov kab mob tsis muaj kab mob thiab cov kab mob hlau oxide. Feem ntau siv cov tshuaj muaj xws li hydrochloric acid, nitric acid, phosphoric acid, thiab citric acid. Cov kua qaub tuaj yeem ua rau cov hlau oxides tsim cov ntsev soluble, yog li tshem tawm cov txheej txheem. Piv txwv li, hydrochloric acid tuaj yeem tshem tawm cov nplai inorganic xws li calcium carbonate thiab ferric hydroxide, thaum citric acid yog softer thiab haum rau lub cev rhiab rau cov ntaub ntawv membrane.
(2) Alkaline ntxuav
Alkaline ntxuav feem ntau yog siv los tshem tawm cov kab mob organic, roj, thiab cov kab mob protein. Cov neeg siv feem ntau suav nrog NaOH, Na₂CO₃, Na₃PO₄, thiab EDTA. Nyob rau hauv alkaline tej yam kev mob, organic teeb meem yuav saponified, proteins denatured, los yog microbial flocs decomposed. Piv txwv li, cov tshuaj NaOH tuaj yeem tshem tawm cov kab mob sib kis tau zoo.
(3) Oxidative ntxuav
Oxidative tu cov neeg ua haujlwm, xws li sodium hypochlorite, hydrogen peroxide, thiab peracetic acid, yog cov oxidants muaj zog uas tuaj yeem oxidize organic kuab paug rau hauv me me, dej -soluble molecules. Lawv txo qhov adhesion ntawm cov pa phem los ntawm kev rhuav tshem lawv cov tshuaj lom neeg, pawg carboxyl, lossis pawg amine. Lawv feem ntau siv rau kev tua kab mob thiab tshem tawm cov organic membrane scale, tab sis nws yuav tsum tau muab sau tseg tias qee cov membranes (xws li aromatic polyamide thim rov qab osmosis membranes) yog rhiab heev rau oxidants.
(4) Surfactant Cleaning
Surfactants, xws li Triton X-100 thiab sodium dodecylbenzene sulfonate (SDBS), tuaj yeem emulsify roj thiab cov proteins thiab disperse cov pa phem. Lawv cov txheej txheem ntawm kev ua haujlwm yog txo qis kev sib tshuam ntawm lub ntsej muag, ua kom cov pa phem yooj yim rau desorb. Surfactant tu yog tshwj xeeb tshaj yog zoo rau oily wastewater los yog zaub mov ua cov dej khib nyiab.
(5) Kev tu kom yooj yim
Feem ntau siv cov tshuaj complexing, xws li ethylenediaminetetraacetic acid (EDTA), tuaj yeem tsim cov complexes ruaj khov nrog cov hlau ions, rhuav tshem cov qauv ntawm inorganic nplai thiab yog li tshem tawm cov hlau deposits. Lawv feem ntau siv ua ke hauv cov tshuab nrog ntau cov pa phem (xws li Ca²⁺-organic acid scale) kom tau txais txiaj ntsig zoo dua. Kev ua tiav ntawm kev tu tshuaj yog ze ze rau qhov concentration, kub, sijhawm, thiab pH ntawm cov tshuaj ntxuav. Hauv kev xyaum, ntau yam tsawg- kev ua kom pom tseeb yog feem ntau siv los txo qhov kev puas tsuaj rau cov khoom siv membrane.
3. Biological Cleaning Kev tu tsiaj yog siv cov tshuaj biocatalytic ntawm cov enzymes los yog cov kab mob kom decompose cov kab mob. Piv txwv li, proteases tuaj yeem decompose cov kab mob protein, lipases tuaj yeem tshem tawm cov roj, thiab cellulases tuaj yeem decompose organic membrane scale. Nws qhov zoo yog tias nws yog me me, ib puag ncig tus phooj ywg, tsis yog - tshuaj lom, thiab ua rau muaj kev puas tsuaj tsawg heev rau cov qauv membrane; nws qhov tsis zoo yog tus nqi siab dua thiab siv tsis tau, thiab nws feem ntau yog siv los ua cov tshuaj ntxuav tes.
II. Kev Tshawb Fawb Txog Kev Tshawb Fawb thiab Kev Qhia Txog Kev Ua Haujlwm Engineering
Los ntawm kev xav txog engineering, kev xaiv cov tswv yim ntxuav cov membrane yuav tsum tau txiav txim siab raws li hom fouling, cov khoom siv membrane, thiab cov txheej txheem ua haujlwm.
Inorganic scale fouling: Acid ntxuav + complexing tus neeg sawv cev yog nyiam;
Organic thiab lom fouling: Alkaline ntxuav + surfactant;
Combined fouling: Tshuaj ntxuav tom qab los ntawm kev ntxuav lub cev los yog alternating tu txoj kev;
Yooj yim oxidized membranes: Tsis txhob siv cov oxidants muaj zog.
Thaum lub sij hawm ntxuav, qhov kub yuav tsum tau tswj (feem ntau 25-40 degree) kom nce cov tshuaj tiv thaiv thaum tiv thaiv daim nyias nyias. Tsis tas li ntawd, kev saib xyuas yuav tsum tau them rau cov kev ncig thiab cov qauv ntws ntawm cov tshuaj ntxuav kom huv si kom zoo shearing ntawm cov tshuaj tua kab mob ntawm daim nyias nyias. Kev ntxuav kom huv yog qhov tseem ceeb tom qab ntxuav kom tsis txhob muaj cov kab mob sib kis los ntawm cov khoom seem.
Cov ntsiab lus
Kev tu cov khoom membrane yog ib kauj ruam tseem ceeb hauv kev ua haujlwm ruaj khov ntawm cov txheej txheem sib cais membrane. Ib txoj kev tu kom zoo tuaj yeem tsis tsuas yog ua kom zoo dua cov txheej txheem ntawm daim nyias nyias, tab sis kuj tseem txuas ntxiv lub neej ntawm daim nyias nyias thiab txo cov nqi khiav haujlwm. Kev tu lub cev yog qhov yooj yim thiab kev lag luam, kev siv tshuaj lom neeg yog qhov zoo thiab siv tau zoo, thiab kev tu tsiaj yog ib puag ncig zoo. Los ntawm kev sib txuas peb txoj hauv kev no, kev nthuav dav thiab tus nqi - cov tshuaj ntxuav tau zoo tuaj yeem tsim los ntawm cov yam ntxwv ntawm fouling. Nyob rau hauv lub neej yav tom ntej, nrog kev txhim kho hauv cov ntaub ntawv membrane thiab kev txhim kho cov thev naus laus zis tu, kev siv tshuaj tsawg tsawg, kev tswj tsis siv neeg, thiab kev ntxuav ntse yuav dhau los ua cov kev taw qhia tseem ceeb. Rau cov kws kho dej kho dej, kev paub txog cov txheej txheem thiab kev ntsuam xyuas cov txheej txheem ntawm kev ntxuav cov membrane yog ib qho tseem ceeb rau kev txhim kho kev ntseeg siab thiab kev lag luam.