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Kev xeb ntawm cov kab mob me me (MIC) yog ib qho teeb meem loj heev hauv ntau lub lag luam, vim nws tuaj yeem ua rau muaj kev poob nyiaj txiag loj heev. Super duplex stainless hlau 2707 (2707 HDSS) siv rau hauv cov chaw nyob hauv dej hiav txwv vim nws cov tshuaj tiv thaiv zoo heev. Txawm li cas los xij, nws txoj kev tiv thaiv rau MIC tsis tau pom los ntawm kev sim. Kev tshawb fawb no tau tshuaj xyuas tus cwj pwm ntawm MIC 2707 HDSS los ntawm cov kab mob aerobic hauv dej hiav txwv Pseudomonas aeruginosa. Kev tshuaj xyuas electrochemical qhia tau hais tias nyob rau hauv qhov muaj Pseudomonas aeruginosa biofilm hauv 2216E nruab nrab, qhov kev hloov pauv zoo hauv qhov muaj peev xwm xeb thiab qhov nce ntxiv ntawm qhov ceev tam sim no xeb tshwm sim. Kev tshuaj xyuas ntawm X-ray photoelectron spectroscopy (XPS) tau qhia txog kev txo qis hauv cov ntsiab lus Cr ntawm qhov chaw ntawm cov qauv hauv qab biofilm. Kev tshuaj xyuas pom ntawm cov qhov av qhia tau hais tias P. aeruginosa biofilm tsim qhov tob tshaj plaws ntawm 0.69 µm thaum 14 hnub ntawm kev sib xyaw. Txawm hais tias qhov no me me, nws qhia tau tias 2707 HDSS tsis muaj zog tiv thaiv MIC ntawm P. aeruginosa biofilms.
Cov hlau tsis xeb duplex (DSS) siv dav hauv ntau yam lag luam vim muaj kev sib xyaw ua ke zoo kawg nkaus ntawm cov khoom siv kho tshuab zoo heev thiab kev tiv thaiv corrosion1,2. Txawm li cas los xij, qhov chaw pitting tseem tshwm sim thiab cuam tshuam rau kev ncaj ncees ntawm cov hlau no3,4. DSS tsis tiv taus microbial corrosion (MIC)5,6. Txawm hais tias muaj ntau yam kev siv rau DSS, tseem muaj ib puag ncig uas qhov kev tiv thaiv corrosion ntawm DSS tsis txaus rau kev siv mus sij hawm ntev. Qhov no txhais tau tias cov ntaub ntawv kim dua nrog kev tiv thaiv corrosion siab dua yog qhov yuav tsum tau ua. Jeon et al7 pom tias txawm tias super duplex stainless steels (SDSS) muaj qee qhov kev txwv hauv kev tiv thaiv corrosion. Yog li ntawd, qee zaum, super duplex stainless steels (HDSS) nrog kev tiv thaiv corrosion siab dua yog qhov yuav tsum tau ua. Qhov no ua rau kev txhim kho ntawm cov hlau alloyed siab.
Kev tiv thaiv xeb DSS nyob ntawm qhov sib piv ntawm alpha thiab gamma theem thiab depleted hauv Cr, Mo thiab W cheeb tsam 8, 9, 10 nyob ib sab ntawm theem thib ob. HDSS muaj cov ntsiab lus siab ntawm Cr, Mo thiab N11, yog li nws muaj kev tiv thaiv xeb zoo heev thiab tus nqi siab (45-50) ntawm qhov sib npaug pitting tiv thaiv tus lej (PREN) txiav txim siab los ntawm wt.% Cr + 3.3 (wt.% Mo + 0.5 wt. .%W) + 16% wt. N12. Nws qhov kev tiv thaiv xeb zoo heev nyob ntawm qhov sib npaug sib xyaw uas muaj kwv yees li 50% ferritic (α) thiab 50% austenitic (γ) theem. HDSS muaj cov khoom siv kho tshuab zoo dua thiab muaj kev tiv thaiv zoo dua rau chloride corrosion. Kev tiv thaiv xeb zoo dua txuas ntxiv kev siv HDSS hauv cov chaw chloride ntau dua xws li cov chaw nyob hauv dej hiav txwv.
MICs yog ib qho teeb meem loj hauv ntau lub lag luam xws li roj thiab roj av thiab dej lag luam14. MIC suav txog 20% ​​ntawm tag nrho cov kev puas tsuaj los ntawm xeb15. MIC yog ib qho kev xeb bioelectrochemical uas tuaj yeem pom hauv ntau qhov chaw ib puag ncig. Cov biofilms uas tsim rau ntawm cov hlau hloov pauv cov xwm txheej electrochemical, yog li cuam tshuam rau cov txheej txheem xeb. Nws ntseeg tau tias MIC xeb yog tshwm sim los ntawm biofilms. Cov kab mob electrogenic noj cov hlau kom tau txais lub zog uas lawv xav tau kom muaj sia nyob17. Cov kev tshawb fawb MIC tsis ntev los no tau qhia tias EET (extracellular electron transfer) yog qhov txwv tus nqi hauv MIC uas tshwm sim los ntawm cov kab mob electrogenic. Zhang et al. 18 tau qhia tias cov neeg nruab nrab electron ua kom nrawm hloov pauv ntawm cov electrons ntawm Desulfovibrio sessificans hlwb thiab 304 stainless hlau, ua rau MIC tawm tsam hnyav dua. Anning et al. 19 thiab Wenzlaff et al. 20 tau qhia tias biofilms ntawm corrosive sulfate-reducing bacteria (SRBs) tuaj yeem nqus cov electrons ncaj qha los ntawm cov hlau substrates, ua rau muaj kev sib tsoo hnyav.
DSS paub tias muaj kev phom sij rau MIC hauv cov xov xwm uas muaj SRBs, cov kab mob txo cov hlau (IRBs), thiab lwm yam. 21. Cov kab mob no ua rau muaj qhov chaw nyob ntawm qhov chaw ntawm DSS hauv qab biofilms22,23. Tsis zoo li DSS, HDSS24 MIC tsis paub zoo.
Pseudomonas aeruginosa yog ib hom kab mob Gram-negative, txav tau yooj yim, zoo li tus pas nrig uas muaj ntau nyob hauv xwm25. Pseudomonas aeruginosa kuj yog ib pawg kab mob loj hauv dej hiav txwv, ua rau muaj MIC ntau ntxiv. Pseudomonas koom nrog hauv cov txheej txheem xeb thiab raug lees paub tias yog tus thawj coj hauv kev tsim cov biofilm. Mahat et al. 28 thiab Yuan et al. 29 tau qhia tias Pseudomonas aeruginosa feem ntau ua rau cov hlau tsis muaj zog thiab cov hlau sib xyaw ua rau cov hlau hauv dej xeb ntau ntxiv.
Lub hom phiaj tseem ceeb ntawm txoj haujlwm no yog los tshawb nrhiav cov khoom ntawm MIC 2707 HDSS uas tshwm sim los ntawm cov kab mob hauv dej hiav txwv Pseudomonas aeruginosa siv cov txheej txheem electrochemical, cov txheej txheem tshuaj xyuas qhov chaw thiab kev tshuaj xyuas cov khoom xeb. Kev tshawb fawb electrochemical, suav nrog qhib lub zog hluav taws xob (OCP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), thiab potential dynamic polarization, tau ua los kawm txog tus cwj pwm ntawm MIC 2707 HDSS. Kev tshuaj xyuas lub zog dispersive spectrometric (EDS) tau ua los ntes cov tshuaj lom neeg ntawm qhov chaw corroded. Tsis tas li ntawd, X-ray photoelectron spectroscopy (XPS) tau siv los txiav txim siab qhov ruaj khov ntawm oxide zaj duab xis passivation nyob rau hauv kev cuam tshuam ntawm ib puag ncig hauv dej hiav txwv uas muaj Pseudomonas aeruginosa. Qhov tob ntawm cov qhov av tau ntsuas nyob rau hauv lub tshuab confocal laser scanning microscope (CLSM).
Rooj 1 qhia txog cov tshuaj lom neeg ntawm 2707 HDSS. Rooj 2 qhia tau tias 2707 HDSS muaj cov khoom siv zoo heev nrog lub zog tso zis ntawm 650 MPa. Ntawm daim duab 1 qhia txog qhov microstructure optical ntawm cov tshuaj kho cua sov 2707 HDSS. Hauv microstructure uas muaj li 50% austenite thiab 50% ferrite theem, cov kab ntev ntawm austenite thiab ferrite theem tsis muaj theem theem ob pom tau.
Hauv daim duab 2a qhia txog qhov qhib lub voj voog muaj peev xwm (Eocp) piv rau lub sijhawm raug rau 2707 HDSS hauv 2216E abiotic medium thiab P. aeruginosa kua zaub rau 14 hnub ntawm 37 ° C. Nws qhia tau hais tias qhov kev hloov pauv loj tshaj plaws thiab tseem ceeb tshaj plaws hauv Eocp tshwm sim hauv 24 teev thawj zaug. Cov nqi Eocp hauv ob qho xwm txheej tau nce siab tshaj plaws ntawm -145 mV (piv rau SCE) nyob ib puag ncig 16 teev thiab tom qab ntawd poob qis heev, ncav cuag -477 mV (piv rau SCE) thiab -236 mV (piv rau SCE) rau cov qauv abiotic. thiab P Pseudomonas aeruginosa coupons, feem). Tom qab 24 teev, tus nqi Eocp 2707 HDSS rau P. aeruginosa ruaj khov ntawm -228 mV (piv rau SCE), thaum tus nqi sib xws rau cov qauv tsis yog biological yog kwv yees li -442 mV (piv rau SCE). Eocp nyob rau hauv lub xub ntiag ntawm P. aeruginosa yog qis heev.
Kev tshawb fawb electrochemical ntawm 2707 HDSS cov qauv hauv abiotic medium thiab Pseudomonas aeruginosa broth ntawm 37 ° C:
(a) Eocp ua haujlwm ntawm lub sijhawm raug, (b) cov kab polarization ntawm hnub 14, (c) Rp ua haujlwm ntawm lub sijhawm raug, thiab (d) icorr ua haujlwm ntawm lub sijhawm raug.
Rooj 3 qhia cov kev ntsuas electrochemical corrosion ntawm 2707 HDSS qauv raug rau abiotic thiab Pseudomonas aeruginosa inoculated media dhau lub sijhawm 14 hnub. Cov tangents ntawm cov anode thiab cathode curves tau extrapolated kom tau txais kev sib tshuam muab corrosion tam sim no ceev (icorr), corrosion potential (Ecorr) thiab Tafel slope (βα thiab βc) raws li cov txheej txheem txheem 30,31.
Raws li pom hauv daim duab 2b, qhov kev hloov pauv mus rau sab saud ntawm P. aeruginosa curve ua rau muaj kev nce ntxiv hauv Ecorr piv rau qhov abiotic curve. Tus nqi icorr, uas yog proportional rau qhov corrosion rate, nce mus txog 0.328 µA cm-2 hauv cov qauv Pseudomonas aeruginosa, uas yog plaub npaug ntau dua li hauv cov qauv tsis yog biological (0.087 µA cm-2).
LPR yog ib txoj kev siv hluav taws xob uas tsis ua rau puas tsuaj rau kev tshuaj xyuas xeb sai. Nws kuj tau siv los kawm MIC32. Hauv daim duab 2c qhia txog qhov tsis kam polarization (Rp) ua lub luag haujlwm ntawm lub sijhawm raug. Tus nqi Rp siab dua txhais tau tias muaj xeb tsawg dua. Hauv 24 teev thawj zaug, Rp 2707 HDSS tau nce mus txog 1955 kΩ cm2 rau cov qauv abiotic thiab 1429 kΩ cm2 rau cov qauv Pseudomonas aeruginosa. Daim duab 2c kuj qhia tau tias tus nqi Rp tau txo qis sai tom qab ib hnub thiab tom qab ntawd tseem tsis hloov pauv ntau dhau 13 hnub tom ntej. Tus nqi Rp ntawm cov qauv Pseudomonas aeruginosa yog li 40 kΩ cm2, uas qis dua tus nqi 450 kΩ cm2 ntawm cov qauv tsis yog biological.
Tus nqi ntawm icorr yog proportional rau qhov sib npaug ntawm corrosion. Nws tus nqi tuaj yeem suav los ntawm cov kab zauv Stern-Giri hauv qab no:
Raws li Zoe et al. 33, tus nqi ib txwm ntawm Tafel slope B hauv txoj haujlwm no tau coj mus rau 26 mV / dec. Daim duab 2d qhia tau hais tias icorr ntawm cov qauv tsis yog biological 2707 tseem ruaj khov, thaum cov qauv P. aeruginosa hloov pauv ntau heev tom qab 24 teev thawj zaug. Cov nqi icorr ntawm P. aeruginosa cov qauv yog qhov kev txiav txim siab ntawm qhov loj dua li cov ntawm cov kev tswj tsis yog biological. Qhov sib txawv no yog sib xws nrog cov txiaj ntsig ntawm kev tiv thaiv polarization.
EIS yog lwm txoj kev tsis puas tsuaj uas siv los piav qhia txog cov tshuaj electrochemical ntawm cov nplaim corroded. Impedance spectra thiab cov nqi capacitance xam ntawm cov qauv uas raug rau ib puag ncig abiotic thiab Pseudomonas aeruginosa kua, passive zaj duab xis / biofilm tsis kam Rb tsim rau ntawm qhov chaw qauv, them hloov tsis kam Rct, hluav taws xob ob txheej capacitance Cdl (EDL) thiab tas mus li QCPE Phase element parameters (CPE). Cov kev ntsuas no tau raug soj ntsuam ntxiv los ntawm kev haum cov ntaub ntawv siv tus qauv sib npaug (EEC).
Hauv daim duab 3 qhia txog cov qauv Nyquist (a thiab b) thiab Bode (a' thiab b') rau 2707 HDSS qauv hauv abiotic media thiab P. aeruginosa broth rau lub sijhawm sib txawv. Lub cheeb tsam ntawm Nyquist ring txo qis thaum muaj Pseudomonas aeruginosa. Daim duab Bode (Daim duab 3b') qhia txog kev nce ntxiv ntawm tag nrho cov impedance. Cov ntaub ntawv hais txog lub sijhawm so tsis tu ncua tuaj yeem tau txais los ntawm theem maxima. Hauv daim duab 4 qhia txog cov qauv lub cev raws li monolayer (a) thiab bilayer (b) thiab EECs sib xws. CPE tau qhia rau hauv EEC qauv. Nws qhov kev nkag mus thiab impedance tau qhia raws li hauv qab no:
Ob lub qauv lub cev thiab cov voj voog sib npaug sib xws rau kev haum rau qhov impedance spectrum ntawm cov qauv 2707 HDSS:
qhov twg Y0 yog tus nqi KPI, j yog tus lej xav lossis (-1)1/2, ω yog lub zaus kaum sab xis, n yog KPI lub zog ntsuas tsawg dua ib qho35. Qhov kev hloov pauv tsis kam ntawm kev them (piv txwv li 1/Rct) sib raug rau qhov nrawm ntawm kev xeb. Rct me dua, qhov nrawm ntawm kev xeb siab dua27. Tom qab 14 hnub ntawm kev sib xyaw, Rct ntawm Pseudomonas aeruginosa cov qauv tau txog 32 kΩ cm2, uas yog tsawg dua li 489 kΩ cm2 ntawm cov qauv tsis yog kab mob (Rooj 4).
Cov duab CLSM thiab cov duab SEM hauv Daim Duab 5 qhia meej meej tias cov txheej biofilm ntawm qhov chaw ntawm HDSS qauv 2707 tom qab 7 hnub yog ntom. Txawm li cas los xij, tom qab 14 hnub, biofilm kev npog tsis zoo thiab qee cov hlwb tuag tau tshwm sim. Rooj 5 qhia qhov tuab biofilm ntawm 2707 HDSS qauv tom qab raug P. aeruginosa rau 7 thiab 14 hnub. Qhov tuab biofilm siab tshaj plaws tau hloov pauv ntawm 23.4 µm tom qab 7 hnub mus rau 18.9 µm tom qab 14 hnub. Qhov nruab nrab biofilm tuab kuj lees paub qhov sib txawv no. Nws txo qis los ntawm 22.2 ± 0.7 μm tom qab 7 hnub mus rau 17.8 ± 1.0 μm tom qab 14 hnub.
(a) duab 3-D CLSM thaum 7 hnub, (b) duab 3-D CLSM thaum 14 hnub, (c) duab SEM thaum 7 hnub, thiab (d) duab SEM thaum 14 hnub.
EMF qhia txog cov tshuaj lom neeg hauv cov biofilms thiab cov khoom xeb ntawm cov qauv uas raug rau P. aeruginosa rau 14 hnub. Hauv daim duab 6 qhia tau hais tias cov ntsiab lus ntawm C, N, O, thiab P hauv biofilms thiab cov khoom xeb yog siab dua li cov hlau ntshiab, vim tias cov ntsiab lus no cuam tshuam nrog biofilms thiab lawv cov metabolites. Cov kab mob me me tsuas xav tau me ntsis ntawm chromium thiab hlau. Cov theem siab ntawm Cr thiab Fe hauv biofilm thiab cov khoom xeb ntawm qhov chaw ntawm cov qauv qhia tau hais tias cov hlau matrix tau poob cov ntsiab lus vim yog xeb.
Tom qab 14 hnub, cov qhov av uas muaj thiab tsis muaj P. aeruginosa tau pom nyob rau hauv nruab nrab 2216E. Ua ntej kev sib xyaw, qhov chaw ntawm cov qauv tau du thiab tsis muaj qhov tsis zoo (Daim duab 7a). Tom qab kev sib xyaw thiab tshem tawm cov biofilm thiab cov khoom xeb, cov qhov av tob tshaj plaws ntawm qhov chaw ntawm cov qauv tau kuaj xyuas siv CLSM, raws li pom hauv Daim duab 7b thiab c. Tsis pom muaj qhov av pom tseeb ntawm qhov chaw ntawm cov kev tswj tsis yog biological (qhov tob tshaj plaws ntawm qhov av 0.02 µm). Qhov tob tshaj plaws ntawm qhov av uas tshwm sim los ntawm P. aeruginosa yog 0.52 µm ntawm 7 hnub thiab 0.69 µm ntawm 14 hnub, raws li qhov nruab nrab qhov tob tshaj plaws ntawm qhov av los ntawm 3 cov qauv (10 qhov tob tshaj plaws tau xaiv rau txhua tus qauv). Kev ua tiav ntawm 0.42 ± 0.12 µm thiab 0.52 ± 0.15 µm, feem (Rooj 5). Cov nqi tob ntawm qhov av no me me tab sis tseem ceeb.
(a) ua ntej raug tus kab mob, (b) 14 hnub nyob rau hauv ib puag ncig abiotic, thiab (c) 14 hnub nyob rau hauv Pseudomonas aeruginosa kua zaub.
Hauv daim duab. Rooj 8 qhia txog cov XPS spectra ntawm ntau qhov chaw kuaj, thiab cov tshuaj lom neeg sib xyaw ua ke rau txhua qhov chaw tau muab sau ua ke hauv Rooj 6. Hauv Rooj 6, feem pua ​​​​​​ntawm Fe thiab Cr nyob rau hauv qhov muaj P. aeruginosa (cov qauv A thiab B) qis dua li cov ntawm cov kev tswj tsis yog biological. (cov qauv C thiab D). Rau cov qauv P. aeruginosa, cov kab nkhaus spectral ntawm qib ntawm Cr 2p nucleus tau haum rau plaub lub ncov nrog lub zog khi (BE) ntawm 574.4, 576.6, 578.3 thiab 586.8 eV, uas tuaj yeem raug suav tias yog Cr, Cr2O3, CrO3. thiab Cr (OH) 3, feem (Daim duab 9a thiab b). Rau cov qauv uas tsis yog biological, cov spectrum ntawm cov theem Cr 2p tseem ceeb muaj ob lub ncov tseem ceeb rau Cr (573.80 eV rau BE) thiab Cr2O3 (575.90 eV rau BE) hauv Figs. 9c thiab d, raws li. Qhov sib txawv tseem ceeb tshaj plaws ntawm cov qauv abiotic thiab cov qauv P. aeruginosa yog qhov muaj Cr6+ thiab qhov sib piv siab dua ntawm Cr(OH)3 (BE 586.8 eV) nyob rau hauv biofilm.
Cov spectra XPS dav dav ntawm qhov chaw ntawm cov qauv 2707 HDSS hauv ob lub xov xwm yog 7 thiab 14 hnub, raws li.
(a) raug kab mob P. aeruginosa 7 hnub, (b) raug kab mob P. aeruginosa 14 hnub, (c) 7 hnub nyob rau hauv ib puag ncig uas tsis muaj sia nyob, thiab (d) 14 hnub nyob rau hauv ib puag ncig uas tsis muaj sia nyob.
HDSS qhia txog qib siab ntawm kev tiv thaiv corrosion hauv feem ntau ib puag ncig. Kim et al.2 tau tshaj tawm tias HDSS UNS S32707 tau txheeb xyuas tias yog DSS uas muaj cov khoom sib xyaw ua ke nrog PREN ntau dua 45. Tus nqi PREN ntawm cov qauv 2707 HDSS hauv txoj haujlwm no yog 49. Qhov no yog vim muaj cov ntsiab lus chromium siab thiab cov ntsiab lus siab ntawm molybdenum thiab nickel, uas muaj txiaj ntsig zoo hauv cov chaw acidic. thiab ib puag ncig nrog cov ntsiab lus chloride siab. Tsis tas li ntawd, cov khoom sib npaug zoo thiab cov qauv tsis muaj qhov tsis zoo yog qhov zoo rau kev ruaj khov ntawm cov qauv thiab kev tiv thaiv corrosion. Txawm li cas los xij, txawm tias nws cov tshuaj tiv thaiv zoo heev, cov ntaub ntawv sim hauv txoj haujlwm no qhia tias 2707 HDSS tsis muaj zog tag nrho rau P. aeruginosa biofilm MICs.
Cov txiaj ntsig electrochemical qhia tau hais tias tus nqi xeb ntawm 2707 HDSS hauv P. aeruginosa broth nce ntxiv ntau tom qab 14 hnub piv rau qhov chaw tsis muaj kab mob. Hauv Daim Duab 2a, qhov txo qis hauv Eocp tau pom ob qho tib si hauv abiotic medium thiab hauv P. aeruginosa broth thaum 24 teev thawj zaug. Tom qab ntawd, biofilm npog tag nrho qhov chaw ntawm cov qauv, thiab Eocp dhau los ua qhov ruaj khov36. Txawm li cas los xij, qib bioclimatic Eocp siab dua qib tsis muaj kab mob. Muaj cov laj thawj ntseeg tias qhov sib txawv no cuam tshuam nrog kev tsim cov P. aeruginosa biofilms. Ntawm daim duab 2d nyob rau hauv qhov muaj P. aeruginosa, tus nqi icorr 2707 HDSS tau mus txog 0.627 μA cm-2, uas yog qhov kev txiav txim siab ntawm qhov loj dua li ntawm abiotic tswj (0.063 μA cm-2), uas yog sib xws nrog tus nqi Rct ntsuas los ntawm EIS. Thaum ob peb hnub thawj zaug, cov nqi impedance hauv P. aeruginosa broth tau nce ntxiv vim yog qhov txuas ntawm P. aeruginosa hlwb thiab kev tsim cov biofilms. Txawm li cas los xij, thaum biofilm npog tag nrho qhov chaw ntawm cov qauv, qhov impedance txo qis. Cov txheej txheem tiv thaiv raug tawm tsam feem ntau vim yog qhov tsim ntawm biofilms thiab biofilm metabolites. Yog li ntawd, qhov kev tiv thaiv corrosion txo qis dhau sijhawm thiab qhov txuas ntawm P. aeruginosa ua rau muaj kev xeb hauv zos. Cov qauv hauv cov chaw abiotic sib txawv. Qhov kev tiv thaiv corrosion ntawm cov kev tswj tsis yog biological siab dua li tus nqi sib xws ntawm cov qauv uas raug rau P. aeruginosa broth. Tsis tas li ntawd, rau abiotic accessions, Rct 2707 HDSS tus nqi tau mus txog 489 kΩ cm2 rau hnub 14, uas yog 15 npaug siab dua li tus nqi Rct (32 kΩ cm2) nyob rau hauv qhov muaj P. aeruginosa. Yog li, 2707 HDSS muaj kev tiv thaiv corrosion zoo heev hauv ib puag ncig sterile, tab sis tsis tiv taus MICs los ntawm P. aeruginosa biofilms.
Cov txiaj ntsig no kuj tuaj yeem pom los ntawm cov kab polarization hauv Figs. 2b. Anodic branching tau cuam tshuam nrog Pseudomonas aeruginosa biofilm tsim thiab cov hlau oxidation reactions. Hauv qhov no, qhov cathodic reaction yog qhov txo qis ntawm oxygen. Qhov muaj P. aeruginosa ua rau muaj qhov corrosion tam sim no ntau ntxiv, txog qhov kev txiav txim ntawm qhov loj dua li hauv kev tswj hwm abiotic. Qhov no qhia tau hais tias P. aeruginosa biofilm txhim kho qhov corrosion hauv zos ntawm 2707 HDSS. Yuan et al.29 pom tias qhov corrosion tam sim no ntawm Cu-Ni 70/30 alloy nce ntxiv nyob rau hauv qhov kev ua ntawm P. aeruginosa biofilm. Qhov no yuav yog vim muaj biocatalysis ntawm kev txo qis oxygen los ntawm Pseudomonas aeruginosa biofilms. Qhov kev soj ntsuam no kuj tseem yuav piav qhia txog MIC 2707 HDSS hauv txoj haujlwm no. Kuj tseem yuav muaj oxygen tsawg dua nyob rau hauv aerobic biofilms. Yog li ntawd, qhov tsis kam rov ua dua qhov chaw hlau nrog oxygen yuav yog ib qho tseem ceeb uas ua rau MIC hauv txoj haujlwm no.
Dickinson et al. 38 tau hais tias qhov nrawm ntawm cov tshuaj lom neeg thiab electrochemical cov tshuaj tiv thaiv tuaj yeem cuam tshuam ncaj qha los ntawm kev ua haujlwm ntawm cov kab mob sessile ntawm qhov chaw kuaj thiab qhov xwm txheej ntawm cov khoom xeb. Raws li pom hauv Daim Duab 5 thiab Rooj 5, tus lej ntawm cov hlwb thiab biofilm tuab txo qis tom qab 14 hnub. Qhov no tuaj yeem piav qhia tau zoo los ntawm qhov tseeb tias tom qab 14 hnub, feem ntau ntawm cov hlwb sessile ntawm qhov chaw ntawm 2707 HDSS tuag vim yog kev noj zaub mov tsis txaus hauv 2216E nruab nrab lossis kev tso tawm cov hlau lom ions los ntawm 2707 HDSS matrix. Qhov no yog qhov txwv ntawm kev sim ua pawg.
Hauv daim ntawv no, ib daim biofilm P. aeruginosa tau pab ua rau Cr thiab Fe poob qis hauv qab daim biofilm ntawm qhov chaw ntawm 2707 HDSS (Daim Duab 6). Daim Ntawv Qhia 6 qhia txog kev txo qis hauv Fe thiab Cr hauv cov qauv D piv rau cov qauv C, qhia tias Fe thiab Cr uas yaj los ntawm daim biofilm P. aeruginosa tseem nyob rau thawj 7 hnub. Ib puag ncig 2216E siv los ua qauv ib puag ncig hauv dej hiav txwv. Nws muaj 17700 ppm Cl-, uas sib piv rau nws cov ntsiab lus hauv dej hiav txwv ntuj. Qhov muaj 17700 ppm Cl- yog qhov laj thawj tseem ceeb rau qhov txo qis hauv Cr hauv 7- thiab 14-hnub cov qauv abiotic uas XPS tau soj ntsuam. Piv rau cov qauv P. aeruginosa, qhov kev yaj ntawm Cr hauv cov qauv abiotic tsawg dua vim yog qhov muaj zog tiv thaiv ntawm 2707 HDSS rau chlorine nyob rau hauv cov xwm txheej abiotic. Ntawm daim duab 9 qhia txog qhov muaj Cr6 + hauv zaj duab xis passivating. Nws yuav koom nrog kev tshem tawm cov chromium ntawm cov hlau los ntawm P. aeruginosa biofilms, raws li Chen thiab Clayton tau hais.
Vim yog cov kab mob loj hlob, cov nqi pH ntawm cov khoom nruab nrab ua ntej thiab tom qab cog qoob loo yog 7.4 thiab 8.2, raws li. Yog li, hauv qab P. aeruginosa biofilm, cov organic acid corrosion tsis zoo li yuav pab txhawb rau txoj haujlwm no vim yog pH siab heev hauv cov khoom nruab nrab. Lub pH ntawm cov khoom nruab nrab tswj tsis yog biological tsis hloov pauv ntau (txij li thaum pib 7.4 mus rau qhov kawg 7.5) thaum lub sijhawm sim 14 hnub. Qhov nce hauv pH hauv cov noob nruab nrab tom qab kev sib xyaw yog vim yog cov haujlwm metabolic ntawm P. aeruginosa thiab pom tias muaj tib yam cuam tshuam rau pH thaum tsis muaj cov ntawv xeem.
Raws li pom hauv Daim Duab 7, qhov tob tshaj plaws ntawm qhov av uas tshwm sim los ntawm P. aeruginosa biofilm yog 0.69 µm, uas yog ntau dua li ntawm cov abiotic medium (0.02 µm). Qhov no yog sib xws nrog cov ntaub ntawv electrochemical piav qhia saum toj no. Qhov tob ntawm qhov av ntawm 0.69 µm yog ntau dua kaum npaug me dua li tus nqi 9.5 µm uas tau tshaj tawm rau 2205 DSS nyob rau hauv tib qho xwm txheej. Cov ntaub ntawv no qhia tau tias 2707 HDSS ua pov thawj zoo dua rau MICs dua li 2205 DSS. Qhov no yuav tsum tsis txhob xav tsis thoob vim 2707 HDSS muaj cov theem Cr siab dua uas muab kev passivation ntev dua, nyuaj dua rau depassivate P. aeruginosa, thiab vim nws cov qauv theem sib npaug yam tsis muaj kev phom sij theem ob ua rau muaj kev puas tsuaj.
Xaus lus, cov qhov MIC tau pom nyob rau ntawm qhov chaw ntawm 2707 HDSS hauv P. aeruginosa kua zaub piv rau cov qhov tsis tseem ceeb hauv qhov chaw abiotic. Cov haujlwm no qhia tau hais tias 2707 HDSS muaj kev tiv thaiv zoo dua rau MIC dua li 2205 DSS, tab sis nws tsis tiv thaiv MIC tag nrho vim yog P. aeruginosa biofilm. Cov txiaj ntsig no pab xaiv cov hlau tsis xeb thiab lub neej ntev rau qhov chaw nyob hauv dej hiav txwv.
Daim coupon rau 2707 HDSS muab los ntawm Northeastern University (NEU) Tsev Kawm Ntawv ntawm Metallurgy hauv Shenyang, Suav teb. Cov khoom sib xyaw ua ke ntawm 2707 HDSS tau qhia hauv Rooj 1, uas tau soj ntsuam los ntawm NEU Materials Analysis thiab Testing Department. Tag nrho cov qauv tau kho rau cov tshuaj khov kho ntawm 1180 ° C rau 1 teev. Ua ntej kev sim xeb, lub npib-puab 2707 HDSS nrog thaj chaw qhib sab saum toj ntawm 1 cm2 tau polished rau 2000 grit nrog silicon carbide sandpaper thiab tom qab ntawd polished nrog 0.05 µm Al2O3 hmoov slurry. Cov sab thiab hauv qab yog tiv thaiv nrog inert xim. Tom qab ziab, cov qauv tau ntxuav nrog dej deionized sterile thiab sterilized nrog 75% (v / v) ethanol rau 0.5 teev. Tom qab ntawd lawv tau cua-ziab hauv qab ultraviolet (UV) lub teeb rau 0.5 teev ua ntej siv.
Cov kab mob Marine Pseudomonas aeruginosa hom MCCC 1A00099 tau yuav los ntawm Xiamen Marine Culture Collection Center (MCCC), Suav teb. Pseudomonas aeruginosa tau loj hlob hauv qab qhov kub thiab txias ntawm 37° C. hauv 250 ml flasks thiab 500 ml iav electrochemical cells siv Marine 2216E kua nruab nrab (Qingdao Hope Biotechnology Co., Ltd., Qingdao, Suav teb). Cov khoom nruab nrab muaj (g/l): 19.45 NaCl, 5.98 MgCl2, 3.24 Na2SO4, 1.8 CaCl2, 0.55 KCl, 0.16 Na2CO3, 0.08 KBr, 0.034 SrCl2, 0.08 SrBr2, 0.022 H3BO3, 0.004 NaSiO3, 0016 6NH26NH3, 3.0016 NH3 5.0 peptone, 1.0 yeast extract thiab 0.1 iron citrate. Autoclave ntawm 121°C rau 20 feeb ua ntej txhaj tshuaj. Suav cov hlwb sessile thiab planktonic nrog lub hemocytometer nyob rau hauv lub teeb microscope ntawm 400x magnification. Qhov concentration pib ntawm planktonic Pseudomonas aeruginosa tam sim ntawd tom qab txhaj tshuaj yog kwv yees li 106 hlwb/ml.
Kev ntsuam xyuas electrochemical tau ua tiav hauv lub iav peb-electrode classic nrog qhov ntim nruab nrab ntawm 500 ml. Daim ntawv platinum thiab saturated calomel electrode (SAE) tau txuas nrog lub reactor los ntawm Luggin capillaries puv nrog cov choj ntsev, uas ua haujlwm ua cov electrodes counter thiab reference, feem. Rau kev tsim cov electrodes ua haujlwm, cov hlau tooj liab rubberized tau txuas rau txhua tus qauv thiab npog nrog epoxy resin, tawm txog 1 cm2 ntawm thaj chaw tsis muaj kev tiv thaiv rau cov electrode ua haujlwm ntawm ib sab. Thaum lub sijhawm ntsuas electrochemical, cov qauv tau muab tso rau hauv 2216E nruab nrab thiab khaws cia ntawm qhov kub thiab txias tas li (37 ° C) hauv lub dab dej da dej. OCP, LPR, EIS thiab cov ntaub ntawv dynamic polarization tau ntsuas siv Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA). Kev ntsuam xyuas LPR tau kaw ntawm tus nqi scan ntawm 0.125 mV s-1 hauv qhov ntau ntawm -5 txog 5 mV nrog Eocp thiab tus nqi kuaj ntawm 1 Hz. EIS tau ua tiav nrog nthwv dej sine hla ntau zaus ntawm 0.01 txog 10,000 Hz siv lub zog hluav taws xob ntawm 5 mV ntawm lub xeev ruaj khov Eocp. Ua ntej lub peev xwm sweep, cov electrodes tau nyob rau hauv hom tsis ua haujlwm kom txog thaum tus nqi ruaj khov ntawm lub peev xwm xeb dawb tau mus txog. Cov kab polarization tau ntsuas los ntawm -0.2 txog 1.5 V ua haujlwm ntawm Eocp ntawm tus nqi scan ntawm 0.166 mV / s. Txhua qhov kev xeem tau rov ua dua 3 zaug nrog thiab tsis muaj P. aeruginosa.
Cov qauv rau kev tshuaj xyuas metallographic tau raug txhuam nrog cov ntawv ntub 2000 grit SiC thiab tom qab ntawd txhuam ntxiv nrog 0.05 µm Al2O3 hmoov rau kev soj ntsuam pom. Kev tshuaj xyuas metallographic tau ua tiav siv lub tshuab tsom iav pom. Cov qauv tau etched nrog 10 wt% kua ntawm potassium hydroxide 43.
Tom qab kev sib xyaw ua ke, cov qauv tau ntxuav 3 zaug nrog phosphate buffered saline (PBS) (pH 7.4 ± 0.2) thiab tom qab ntawd kho nrog 2.5% (v/v) glutaraldehyde rau 10 teev kom kho cov biofilms. Tom qab ntawd nws tau qhuav nrog batched ethanol (50%, 60%, 70%, 80%, 90%, 95% thiab 100% los ntawm ntim) ua ntej cua qhuav. Thaum kawg, ib zaj duab xis kub tau tso rau ntawm qhov chaw ntawm cov qauv kom muab kev coj ua rau SEM soj ntsuam. Cov duab SEM tau tsom mus rau cov chaw uas muaj cov hlwb P. aeruginosa sessile tshaj plaws ntawm qhov chaw ntawm txhua tus qauv. Ua qhov kev tshuaj xyuas EDS kom nrhiav tau cov tshuaj lom neeg. Lub Zeiss confocal laser scanning microscope (CLSM) (LSM 710, Zeiss, Lub Tebchaws Yelemees) tau siv los ntsuas qhov tob ntawm qhov av. Txhawm rau soj ntsuam cov qhov av xeb hauv qab cov biofilm, cov qauv kuaj tau raug ntxuav ua ntej raws li Suav Tebchaws Standard (CNS) GB / T4334.4-2000 kom tshem tawm cov khoom xeb thiab biofilm ntawm qhov chaw ntawm cov qauv kuaj.
Kev tshuaj xyuas X-ray photoelectron spectroscopy (XPS, ESCALAB250 surface analysis system, Thermo VG, USA) tau ua tiav los ntawm kev siv lub monochromatic X-ray source (Aluminium Kα line nrog lub zog ntawm 1500 eV thiab lub zog ntawm 150 W) hauv ntau yam kev sib txuas lus 0 nyob rau hauv cov xwm txheej txheem ntawm -1350 eV. Cov spectra daws teeb meem siab tau kaw tseg siv lub zog kis ntawm 50 eV thiab ib kauj ruam ntawm 0.2 eV.
Cov qauv uas tau muab tso rau hauv qhov chaw mos tau raug tshem tawm thiab ntxuav maj mam nrog PBS (pH 7.4 ± 0.2) rau 15 s45. Txhawm rau saib xyuas kev muaj sia nyob ntawm cov kab mob ntawm cov qauv, cov biofilms tau siv cov khoom siv LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA). Cov khoom siv muaj ob hom xim fluorescent: SYTO-9 xim ntsuab fluorescent thiab propidium iodide (PI) xim liab fluorescent. Hauv CLSM, cov xim ntsuab fluorescent thiab cov xim liab sawv cev rau cov hlwb muaj sia thiab tuag, raws li. Rau kev siv cov xim, 1 ml ntawm cov khoom sib xyaw uas muaj 3 µl ntawm SYTO-9 thiab 3 µl ntawm cov kua PI tau muab tso rau hauv qhov chaw mos rau 20 feeb ntawm chav tsev kub (23 ° C) hauv qhov tsaus ntuj. Tom qab ntawd, cov qauv xim tau kuaj xyuas ntawm ob qhov wavelengths (488 nm rau cov hlwb muaj sia thiab 559 nm rau cov hlwb tuag) siv Nikon CLSM apparatus (C2 Plus, Nikon, Nyiv). Lub biofilm thickness tau ntsuas hauv 3D scanning hom.
Yuav hais li cas rau tsab xov xwm no: Li, H. et al. Kev xeb ntawm cov kab mob me me ntawm 2707 super duplex stainless hlau los ntawm Pseudomonas aeruginosa marine biofilm. kev tshawb fawb. 6, 20190. doi: 10.1038/srep20190 (2016).
Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Kev tawg ntawm kev ntxhov siab ntawm LDX 2101 duplex stainless hlau hauv cov tshuaj chloride nyob rau hauv qhov muaj thiosulphate. Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Kev tawg ntawm kev ntxhov siab ntawm LDX 2101 duplex stainless hlau hauv cov tshuaj chloride nyob rau hauv qhov muaj thiosulphate. Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Коррозионное растрескивание под напряжением дуплексной нержавтающей растворах хлоридов в присутствии тиосульфата. Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Kev tawg ntawm kev ntxhov siab ntawm cov hlau duplex stainless hlau LDX 2101 hauv cov tshuaj chloride nyob rau hauv qhov muaj thiosulfate. Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. LDX 2101双相不锈钢在硫代硫酸盐存在下氯化物溶液中的应力腐蚀开裂。 Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. LDX 2101 双相stainless steel 在福代sulfate分下下南性耧生于中囧患像。 Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Коррозионное растрескивание под напряжением дуплексной нержавтающей растворе хлорида в присутствии тиосульфата. Zanotto, F., Grassi, V., Balbo, A., Monticelli, C. & Zucchi, F. Kev tawg ntawm kev ntxhov siab ntawm cov hlau duplex stainless hlau LDX 2101 hauv cov tshuaj chloride nyob rau hauv qhov muaj thiosulfate.coros science 80, 205–212 (2014).
Kim, ST, Jang, SH, Lee, IS & Park, YS Cov teebmeem ntawm kev kho cua sov thiab nitrogen hauv cov roj shielding ntawm kev tiv thaiv pitting corrosion ntawm hyper duplex stainless steel welds. Kim, ST, Jang, SH, Lee, IS & Park, YS Cov teebmeem ntawm kev kho cua sov thiab nitrogen hauv cov roj shielding ntawm kev tiv thaiv pitting corrosion ntawm hyper duplex stainless steel welds.Kim, ST, Jang, SH, Lee, IS thiab Park, YS Cov nyhuv ntawm kev kho cua sov thiab nitrogen hauv cov roj shielding ntawm qhov kev tiv thaiv corrosion pitting ntawm hyperduplex stainless hlau welds. Kim, ST, Jang, SH, Lee, IS & Park, YS. Kim, ST, Jang, SH, Lee, IS & Park, YSKim, ST, Jang, SH, Lee, IS thiab Park, YS Cov nyhuv ntawm kev kho cua sov thiab nitrogen hauv cov roj shielding ntawm qhov tsis kam corrosion ntawm super duplex stainless hlau welds.koros. kev tshawb fawb. 53, 1939–1947 (2011).
Shi, X., Avci, R., Geiser, M. & Lewandowski, Z. Kev kawm sib piv hauv chemistry ntawm microbically thiab electrochemically induced pitting ntawm 316L stainless hlau. Shi, X., Avci, R., Geiser, M. & Lewandowski, Z. Kev kawm sib piv hauv chemistry ntawm microbically thiab electrochemically induced pitting ntawm 316L stainless hlau.Shi, X., Avchi, R., Geyser, M. thiab Lewandowski, Z. Kev kawm sib piv tshuaj lom neeg ntawm microbiological thiab electrochemical pitting ntawm 316L stainless hlau. Shi, X., Avci, R., Geiser, M. & Lewandowski, Z. 微生物和电化学诱导的316L不锈钢点蚀的化学比较研究. Shi, X., Avci, R., Geiser, M. & Lewandowski, Z.Shi, X., Avchi, R., Geyser, M. thiab Lewandowski, Z. Kev kawm txog tshuaj sib piv ntawm cov kab mob microbiological thiab electrochemically induced pitting hauv 316L stainless hlau.koros. kev tshawb fawb. 45, 2577–2595 (2003).
Luo, H., Dong, CF, Li, XG & Xiao, K. Tus cwj pwm electrochemical ntawm 2205 duplex stainless hlau hauv cov kua alkaline nrog pH sib txawv nyob rau hauv qhov muaj chloride. Luo, H., Dong, CF, Li, XG & Xiao, K. Tus cwj pwm electrochemical ntawm 2205 duplex stainless hlau hauv cov kua alkaline nrog pH sib txawv nyob rau hauv qhov muaj chloride.Luo H., Dong KF, Lee HG thiab Xiao K. Kev coj cwj pwm electrochemical ntawm duplex stainless hlau 2205 hauv cov kua alkaline nrog pH sib txawv nyob rau hauv qhov muaj chloride. Luo, H., Dong, CF, Li, XG & Xiao, K. 2205 双相不锈钢在氯化物存在下不同pH 碱性溶液中的电化学行。 Luo, H., Dong, CF, Li, XG & Xiao, K. 2205 Tus cwj pwm electrochemical ntawm 双相stainless hlau nyob rau hauv lub xub ntiag ntawm chloride ntawm pH sib txawv hauv alkaline kua.Luo H., Dong KF, Lee HG thiab Xiao K. Kev coj cwj pwm electrochemical ntawm duplex stainless hlau 2205 hauv cov kua alkaline nrog pH sib txawv nyob rau hauv qhov muaj chloride.Electrochem. Magazine. 64, 211–220 (2012).
Little, BJ, Lee, JS & Ray, RI Qhov cuam tshuam ntawm cov biofilms marine rau kev xeb: Kev tshuaj xyuas luv luv. Little, BJ, Lee, JS & Ray, RI Qhov cuam tshuam ntawm cov biofilms marine rau kev xeb: Kev tshuaj xyuas luv luv.Little, BJ, Lee, JS thiab Ray, RI Cov teebmeem ntawm Marine Biofilms rau Corrosion: Kev Tshuaj Xyuas Luv Luv. Little, BJ, Lee, JS & Ray, RI 海洋生物膜对腐蚀的影响：简明综述. Me, BJ, Lee, JS & Ray, RILittle, BJ, Lee, JS thiab Ray, RI Cov teebmeem ntawm Marine Biofilms rau Corrosion: Kev Tshuaj Xyuas Luv Luv.Electrochem. Magazine. 54, 2-7 (2008).