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I-Microbial corrosion (MIC) iyinkinga enkulu ezimbonini eziningi njengoba ingabangela ukulahlekelwa okukhulu kwezomnotho.I-2707 super duplex stainless steel (2707 HDSS) isetshenziswe ezindaweni zasolwandle ngenxa yokumelana kwayo namakhemikhali okuhle kakhulu.Kodwa-ke, ukumelana kwayo ne-MIC akuzange kuboniswe ngokuhlolwa. i-aeruginosa yaphenywa.Ukuhlaziywa kwe-electrochemical kwabonisa ukuthi phambi kwe-Pseudomonas aeruginosa biofilm ku-2216E medium, kube noshintsho oluhle emandleni okugqwala kanye nokwanda kokugqwala kwamanje. I-aeruginosa biofilm ikhiqize ukujula komgodi okuphezulu okungu-0.69 μm phakathi nezinsuku eziyi-14 zokufukamela. Nakuba lokhu kukuncane, kubonisa ukuthi i-2707 HDSS ayivikelekile ngokugcwele ku-MIC ye-P. aeruginosa biofilms.
I-Duplex stainless steels (DSS) isetshenziswa kakhulu ezimbonini ezihlukahlukene ngokuhlanganiswa kwayo okuhle kwezinto ezinhle kakhulu zemishini kanye nokumelana nokugqwala1,2.Nokho, umgodi wendawo usaqhubeka usenzeka futhi uthinta ubuqotho bale steel3,4.DSS ayimelani nokugqwala kwe-microbial (MIC)5,6.Naphezu kobubanzi obubanzi bokusebenza kwe-DSS okwanele, i-DSS isekhona ukumelana ne-DSS lapho i-corrosion isekhona ngokwanele ukuze zisetshenziswe isikhathi eside.Lokhu kusho ukuthi kudingeka izinto ezibiza kakhulu ezinokumelana nokugqwala okuphezulu.UJeon et al7 bathole ukuthi ngisho nezinsimbi ezingenasici ze-duplex (SDSS) zinemikhawulo ethile mayelana nokumelana nokugqwala.Ngakho-ke, izinsimbi ezingenasici ze-super duplex (HDSS) ezinokumelana nokugqwala okuphezulu ziyadingeka kwezinye izinhlelo zokusebenza.Lokhu kuholele ekuthuthukisweni kwe-HDSS enengxubevange ephezulu.
Ukumelana nokugqwala kwe-DSS kuncike esilinganisweni sezigaba ze-alpha ne-gamma kanye ne-Cr, Mo kanye ne-W izifunda eziqediwe ezingu-8, 9, 10 eziseduze nesigaba sesibili.I-HDSS iqukethe okuqukethwe okuphezulu kwe-Cr, Mo ne-N11, ngakho inokumelana nokugqwala okuhle kakhulu kanye nenani eliphezulu (45-50) I-Pitting Resistance Equistance (PREN) enqunywa nge-Cr +3% Equilition Equilement + 3%. (wt.% Mo + 0.5 wt% W) + 16 wt% N12.Ukumelana kwayo okuhle kakhulu kokugqwala kuncike ekubunjweni okulinganiselayo okuqukethe cishe izigaba ze-50% ze-ferrite (α) kanye ne-50% austenite (γ), i-HDSS inezakhiwo ezingcono zemishini nokumelana okuphezulu kune-DSS13 evamile. Izakhiwo ze-Chloride corrosion.Ukumelana nokugqwala okuthuthukisiwe kwandisa ukusetshenziswa kwe-HDSS ezindaweni ezigqwalile ze-chloride, njengendawo yasolwandle.
Ama-MIC ayinkinga enkulu ezimbonini eziningi ezifana nezinsiza zikawoyela negesi kanye namanzi14.I-MIC yenza u-20% wawo wonke umonakalo wokugqwala15.MIC ukugqwala kwe-bioelectrochemical okungabonwa ezindaweni eziningi.Amafilimu e-biofilm akha ezindaweni zensimbi ashintsha izimo ze-electrochemical, ngaleyo ndlela athinte inqubo yokugqwala okukholelwa ukuthi i-MIC ibangelwa ukugqwala okubanzi. ama-biofilms.Ama-Electrogenic microorganisms agqwalisa izinsimbi ukuze athole amandla asekelayo ukuze aphile17.Ucwaningo lwakamuva lwe-MIC lubonise ukuthi i-EET (ukudluliselwa kwe-electron engaphandle kweseli) iyisici esinciphisa izinga ku-MIC esibangelwa ama-electrogenic microorganisms.Zhang et al. I-18 ibonise ukuthi abaxhumanisi be-electron basheshisa ukudluliswa kwe-electron phakathi kwamaseli e-Desulfovibrio sessificans kanye ne-304 yensimbi engagqwali, okuholela ekuhlaselweni okunzima kakhulu kwe-MIC.Enning et al. 19 kanye noVenzlaff et al. 20 ibonise ukuthi amabhaktheriya e-corrosive sulfate-reducing (SRB) biofilms angamunca ngokuqondile ama-electron asuka kuma-substrates ensimbi, okuholela ekugqwaleni okukhulu kwemigodi.
I-DSS yaziwa ngokungenwa kalula yi-MIC ezindaweni eziqukethe i-SRB, amagciwane e-iron-reducing (IRB), njll. 21 .Lawa magciwane abangela umgodi wendawo endaweni ye-DSS ngaphansi kwe-biofilms22,23.Ngokungafani ne-DSS, i-MIC ye-HDSS24 ayaziwa kahle.
I-Pseudomonas aeruginosa iyi-bacterium emise okwe-gram-negative motile esakazwa kabanzi emvelweni25.I-Pseudomonas aeruginosa iphinde ibe yiqembu elikhulu le-microbial endaweni yasolwandle, okwenza i-MIC ibe yinsimbi.I-Pseudomonas ihileleke kakhulu ezinqubweni zokubola futhi ibonakala njengephayona le-almafilmt e-biomafilm. 28 kanye noYuan et al. 29 ibonise ukuthi i-Pseudomonas aeruginosa inomkhuba wokwandisa izinga lokugqwala kwensimbi ethambile nama-alloys ezindaweni ezinamanzi.
Inhloso eyinhloko yalo msebenzi bekuwukuphenya izakhiwo ze-MIC ze-2707 HDSS ezibangelwa i-marine aerobic bacterium i-Pseudomonas aeruginosa isebenzisa izindlela ze-electrochemical, amasu okuhlaziya umphezulu kanye nokuhlaziywa komkhiqizo wokugqwala. I-Dynamic Polarization yenziwe ukuze kufundwe ukuziphatha kwe-MIC kwe-2707 HDSS.Ukuhlaziywa kwe-Energy dispersive spectrometer (EDS) kwenziwa ukuze kutholwe izakhi zamakhemikhali endaweni egqwalile.Ngaphezu kwalokho, ukuhlaziywa kwe-X-ray photoelectron spectroscopy (XPS) kwasetshenziswa ukuze kutholwe ukuzinza kwefilimu ye-oxide passivation ngaphansi kwethonya lendawo yasolwandle elinganiselwe equkethe ukujula kwe-pietrugonosa laser. isibonakhulu (CLSM).
Ithebula 1 libala ukwakheka kwamakhemikhali kwe-2707 HDSS.Ithebula lesi-2 libonisa ukuthi i-2707 HDSS inezakhiwo ezinhle kakhulu zemishini ezinamandla okukhiqiza angu-650 MPa.Umfanekiso 1 ubonisa i-optical microstructure yokushisa kwesisombululo esiphathwe nge-2707 HDSS.Amabhande amade wezigaba ze-austenite ne-ferrite ngaphandle kwezigaba zesibili ze-austening 500% eziqukethe i-microstructure equkethe i-500%. izigaba ze-ferrite.
Umfanekiso 2a ubonisa amandla okujikeleza avulekile (Eocp) ngokumelene nedatha yesikhathi sokuchayeka ye-2707 HDSS ku-abiotic 2216E medium kanye ne-P. aeruginosa umhluzi izinsuku ezingu-14 ku-37 °C.Kubonisa ukuthi ushintsho olukhulu nolubalulekile ku-Eocp lwenzeka phakathi namahora angu-24 okuqala. 16 h yase yehla kakhulu, yafinyelela -477 mV (vs. SCE) kanye -236 mV (vs. SCE) yesampula ye-abiotic kanye no-P, ngokulandelanayo ). I-Pseudomonas aeruginosa amakhuphoni, ngokulandelanayo.Ngemva kwamahora angu-24, inani le-Eocp elingu-2707 HDSS le-P. aeruginosa lalizinzile ngokuqhathaniswa kokuthi -228 mV (vs. SCE), kuyilapho inani elihambisanayo lamasampuli angewona awebhayoloji lalicishe libe ngu- -442 mV (vs. I-SCE esikhundleni sokuba khona kwe-Porugino ephansi).
Ukuhlolwa kwe-Electrochemical kwezibonelo ze-2707 HDSS ku-abiotic medium kanye nomhluzi we-Pseudomonas aeruginosa ku-37 °C:
(a) I-Eocp njengomsebenzi wesikhathi sokuchayeka, (b) ijika le-polarization ngosuku 14, (c) Rp njengomsebenzi wesikhathi sokuchayeka kanye (d) ne-icorr njengomsebenzi wesikhathi sokuchayeka.
Ithebula 3 ibala amanani wepharamitha yokugqwala kwe-electrochemical yamasampuli angu-2707 HDSS achayeka ku-abiotic medium kanye ne-Pseudomonas aeruginosa inoculated medium izinsuku eziyi-14. Ama-tangents amajika e-anodic kanye ne-cathodic akhishwa ukuze afike ezimpambanweni ezikhiqiza ukugqwala okunamandla (corrosion current) kanye ne-corrosion yamanje (i-corrosion) amamithambeka (βα kanye no-βc) ngokwezindlela ezijwayelekile30,31.
Njengoba kuboniswe kuMfanekiso 2b, ukushintshwa okuya phezulu kwejika le-P. aeruginosa kubangele ukwanda kwe-Ecorr uma kuqhathaniswa nejika le-abiotic.Inani le-icorr, elilingana nezinga lokugqwala, lenyuke laya ku-0.328 μA cm-2 ku-Pseudomonas aeruginosa isampula, μ Aeruginosa izikhathi ezine ze-μA-7 izikhathi ezine ze-biological).
I-LPR iyindlela yakudala ye-electrochemical engabhubhisi yokuhlaziya ukugqwala okusheshayo.Yaphinde yasetshenziselwa ukutadisha i-MIC32.Umfanekiso 2c ubonisa ukumelana ne-polarization (Rp) njengomsebenzi wesikhathi sokuchayeka.Inani eliphakeme le-Rp lisho ukugqwala okuncane. Phakathi namahora okuqala angu-24, i-Rp engu-2707 HDSS ifinyelele inani eliphakeme lama-5 kbiotic angu-9 cm kanye ne-9 kbiotic 9 cm ephezulu I-kΩ cm2 yamasampuli e-Pseudomonas aeruginosa.Umdwebo 2c uphinda ubonise ukuthi inani le-Rp lehle ngokushesha ngemva kosuku olulodwa futhi lahlala lingashintshile uma kuqhathaniswa izinsuku ezizayo eziyi-13. Inani le-Rp lesampula le-Pseudomonas aeruginosa licishe libe ngu-40 kΩ cm2, elingaphansi kakhulu kunenani elingelona elingu-cm20 lesampula elingu-cm20 kΩ.
Inani le-icorr lilingana nezinga lokugqwala elifanayo.Inani layo lingabalwa kusukela kuzibalo ezilandelayo ze-Stern-Geary,
Ukulandela uZou et al. 33, inani elijwayelekile le-Tafel slope B kulo msebenzi lithathwe njengokungu-26 mV/dec. Umfanekiso 2d ubonisa ukuthi i-icorr yesampula engeyona eyebhayoloji engu-2707 ihlale izinzile, kuyilapho isampula ye-P. aeruginosa iguquguquka kakhulu ngemva kwamahora angu-24 okuqala. kunezilawuli ezingezona ezebhayoloji.Lokhu kuthambekela kuhambisana nemiphumela yokumelana ne-polarization.
I-EIS ingenye indlela engonakali esetshenziselwa ukuveza ukusabela kwe-electrochemical ezindaweni ezigqwalile.I-Impedance spectra kanye namanani okubalwa amandla ezibonelo ezivezwe kumidiya ye-abiotic kanye nesixazululo se-Pseudomonas aeruginosa, ukumelana ne-Rb kwefilimu/ifilimu ye-biofilm okwakhiwa phezu kwesifanekiso, ukumelana nogesi we-Rct ukushaja, i-Cdl capital ye-Cdl capetant Amapharamitha we-Phase Element (CPE).Le mingcele yabuye yahlaziywa ngokufaka idatha kusetshenziswa imodeli yesekethe elinganayo (EEC).
Umfanekiso wesi-3 ubonisa iziza ze-Nyquist ezijwayelekile (a no-b) kanye neziza ze-Bode (a' kanye ne-b') zamasampula e-HDSS angu-2707 ku-abiotic medium kanye nomhluzi we-P. aeruginosa ngezikhathi ezihlukene zokufukamela.Ububanzi bendandatho ye-Nyquist buyancipha uma kukhona i-Pseudomonas aeruginosa. I-impedance.Ulwazi mayelana nesikhathi sokuphumula esingaguquki singanikezwa yi-phase maxima.Umfanekiso 4 ubonisa i-monolayer (a) ne-bilayer (b) izakhiwo ezisekelwe ngokomzimba kanye nama-EEC azo ahambisanayo.CPE yethulwa kumodeli we-EEC.Ukuvuma nokuvinjelwa kwayo kuvezwa kanje:
Amamodeli amabili angokomzimba namasekhethi ahambisanayo afanayo wokufaka i-spectrum ye-impedance yesifanekiso se-2707 HDSS:
lapho i-Y0 iwubukhulu be-CPE, j inombolo ecatshangelwayo noma (-1) 1/2, ω imvamisa ye-angular, futhi n inkomba yamandla e-CPE engaphansi kobunye35.I-inverse of the charge transfer resistance (okungukuthi 1/Rct) ihambisana nezinga lokugqwala.I-Rct encane isho ukuthi i-corrosion rate ye-Rct 27 esheshayo yezinsuku ezingu-27. Amasampuli e-Pseudomonas aeruginosa afinyelele ku-32 kΩ cm2, mancane kakhulu kuno-489 kΩ cm2 wamasampuli angewona awebhayoloji (Ithebula 4).
Izithombe ze-CLSM nezithombe ze-SEM kumfanekiso wesi-5 zibonisa ngokusobala ukuthi ukumbozwa kwe-biofilm ebusweni besampula ye-HDSS engu-2707 ngemva kwezinsuku ezingu-7 kuminyene. Nokho, ngemva kwezinsuku eziyi-14, ukumbozwa kwe-biofilm bekumbalwa futhi kwavela amaseli afile. Ugqinsi lwe-biofilm lushintshile lusuka ku-23.4 μm ngemva kwezinsuku ezingu-7 lwaya ku-18.9 μm ngemva kwezinsuku ezingu-14. Ukuqina kwe-biofilm okumaphakathi nakho kwaqinisekisa lokhu kuthambekela.Yehla ukusuka ku-22.2 ± 0.7 μm ngemva kwezinsuku ezingu-7 kuya ku-17.8 ± 1.0 μm ngemva kwezinsuku eziyi-14.
(a) Isithombe se-3-D CLSM ngemva kwezinsuku ezingu-7, (b) isithombe se-3-D CLSM ngemva kwezinsuku eziyi-14, (c) Isithombe se-SEM ngemva kwezinsuku ezingu-7 kanye (d) nesithombe se-SEM ngemva kwezinsuku eziyi-14.
I-EDS yembule izakhi zamakhemikhali kuma-biofilms kanye nemikhiqizo yokugqwala kumasampuli adalulwe ku-P. aeruginosa izinsuku ezingu-14. Umfanekiso 6 ubonisa ukuthi okuqukethwe kwe-C, N, O, no-P ku-biofilms nemikhiqizo yokugqwala kuphakeme kakhulu kunalokho okusezinsimbi ezingenalutho, ngoba lezi zakhi zihlotshaniswa nama-biofilms kanye nama-metabolites awo.Ama-microbes we-iron kanye namazinga e-iron aphezulu adinga kuphela inani le-iron chromi Imikhiqizo ye-biofilm kanye ne-corrosion ebusweni bezibonelo ibonisa ukuthi i-matrix yensimbi ilahlekelwe izakhi ngenxa yokugqwala.
Ngemva kwezinsuku ezingu-14, umgodi onama-P. aeruginosa nangaphandle kwawo wawubonwa ku-2216E medium.Ngaphambi kokufakwa kwe-incubation, indawo yesampula yayibushelelezi futhi ingenasici (Fig. 7a) .Ngemva kokufakwa nokususwa kwemikhiqizo ye-biofilm kanye ne-corrosion, imigodi ejulile ebusweni bezibonelo yahlolwa njengoba kuboniswe ngaphansi kwe-7 clNo. indawo yamasampula okulawula okungewona awebhayoloji (ubukhulu bokujula komgodi okungu-0.02 μm). Ukujula komgodi okuphezulu okubangelwa i-Pseudomonas aeruginosa kwaba ngu-0.52 μm ngemva kwezinsuku ezingu-7 kanye no-0.69 μm ngemva kwezinsuku ezingu-14, ngokusekelwe ekujuleni komgodi okuphezulu kwamasampuli angu-3 (umgodi omkhulu oyi-10 ofinyelelwe ngu-0 amasampula 0. μm kanye no-0.52 ± 0.15 μm, ngokulandelanayo (Ithebula 5). Lawa manani wokujula komgodi mancane kodwa abalulekile.
(a) Ngaphambi kokuchayeka, (b) izinsuku eziyi-14 ku-abiotic medium kanye (c) nezinsuku eziyi-14 kumhluzi we-Pseudomonas aeruginosa.
Umfanekiso 8 ubonisa i-spectra ye-XPS yezindawo zesampula ezihlukene, futhi ukwakheka kwamakhemikhali okuhlaziywe kwendawo ngayinye kufinyezwa kuThebula 6.Kuthebula lesi-6, amaphesenti e-athomu e-Fe ne-Cr ebukhoneni be-P. aeruginosa (amasampuli A no-B) abephansi kakhulu kunalawo amasampuli okulawula okungewona awebhayoloji (amasampula C, amasampula C, amasampula e-Cr2). Ijika le-spectral leleveli eyinhloko lalifakwe ezingxenyeni ezine eziphezulu ezinamandla abophezelayo (BE) amanani angu-574.4, 576.6, 578.3 kanye no-586.8 eV, okungabalulwa ku-Cr, Cr2O3, CrO3 kanye ne-Cr(OH)3, ngokulandelanayo, i-non-biological specimen. I-spectrum yeleveli eyinhloko engu-2p iqukethe iziqongo ezimbili eziyinhloko ze-Cr (573.80 eV ye-BE) kanye ne-Cr2O3 (575.90 eV ye-BE) ku-Fig. 9c kanye no-d, ngokulandelana. eV) ngaphansi kwe-biofilm.
I-spectra ebanzi ye-XPS yobuso besampula ye-2707 HDSS kumidiya emibili yizinsuku eziyi-7 nezinsuku eziyi-14, ngokulandelana.
(a) Izinsuku eziyi-7 zokuchayeka ku-P. aeruginosa, (b) izinsuku eziyi-14 zokuchayeka ku-P. aeruginosa, (c) izinsuku eziyi-7 ku-abiotic medium kanye (d) nezinsuku eziyi-14 endaweni ye-abiotic.
I-HDSS ibonisa amazinga aphezulu okumelana nokugqwala ezindaweni eziningi.Kim et al. I-2 ibike ukuthi i-UNS S32707 HDSS ichazwe njenge-DSS enengxubevange ephezulu ene-PREN engaphezu kuka-45. Inani le-PREN lesampula le-2707 HDSS kulo msebenzi lalingu-49. Lokhu kungenxa yokuqukethwe kwayo okuphezulu kwe-chromium namazinga aphezulu e-molybdenum kanye ne-Ni, okunenzuzo endaweni ene-acidic kanye ne-high defect-free-chloride. i-microstructure iwusizo ekuzinzeni kwesakhiwo nokumelana nokugqwala.Nokho, naphezu kokumelana kwayo okuhle kakhulu namakhemikhali, idatha yokuhlola kulo msebenzi iphakamisa ukuthi i-2707 HDSS ayivikelekile ngokuphelele ku-MIC ye-P. aeruginosa biofilms.
Imiphumela ye-electrochemical ibonise ukuthi izinga lokugqwala kwe-2707 HDSS ku-P. aeruginosa umhluzi landa kakhulu ngemva kwezinsuku ezingu-14 uma kuqhathaniswa ne-non-biological medium. Emfanekisweni we-2a, ukuncipha kwe-Eocp kwabonwa kokubili okuphakathi kwe-abiotic kanye nomhluzi we-P. aeruginosa phakathi namahora angu-24 okuqala. izinzile36.Nokho, izinga le-Eocp yezinto eziphilayo laliphezulu kakhulu kunalelo le-Eocp engeyona eyebhayoloji.Kunesizathu sokukholelwa ukuthi lo mehluko ubangelwa ukwakheka kwe-biofilm ye-P. aeruginosa.Kumfanekiso we-2d, phambi kwe-P. aeruginosa, inani le-icorr lika-2707 le-HDSS elifinyelele ku-μA ye-HDSS ephakeme ngo-0. leyo yokulawulwa kwe-abiotic (0.063 μA cm-2), eyayihambisana nenani le-Rct elikalwe yi-EIS. Phakathi nezinsuku ezimbalwa zokuqala, amanani e-impedance ku-P. aeruginosa umhluzi anda ngenxa yokunamathiselwa kwamaseli e-P. aeruginosa kanye nokwakhiwa kwama-biofilms. ukwakheka kwama-biofilms kanye nama-metabolites e-biofilm.Ngakho-ke, ukumelana nokugqwala kwehle ngokuhamba kwesikhathi, futhi okunamathiselwe kwe-P. aeruginosa kubangele ukugqwala kwendawo.Izitayela zemidiya ye-abiotic zazihlukile.Ukumelana nokugqwala kokulawulwa okungezona kwebhayoloji kwakuphakeme kakhulu kunevelu ehambisanayo yamasampuli adalulwe ku-P. aeruginosa isampula ye-Rederuginosa, i-Red aeruginosa. I-2707 HDSS ifinyelele ku-489 kΩ cm2 ngosuku lwe-14, okwakuphindwe izikhathi ezingu-15 inani le-Rct (32 kΩ cm2) phambi kwe-P. aeruginosa.Ngakho-ke, i-2707 HDSS inokumelana nokugqwala okuhle kakhulu endaweni eyinyumba, kodwa ayimelani nokuhlaselwa kwe-MIC yi-P. aeruginosa
Le miphumela ingabuye ibonwe kusukela kuma-polarization curves ku-Fig. 2b.I-anodic branching kuthiwa ibangelwa i-Pseudomonas aeruginosa biofilm formation kanye nokusabela kwe-oxidation yensimbi.Ngaso leso sikhathi ukusabela kwe-cathodic ukuncishiswa kwe-oxygen.Ukuba khona kwe-P. aeruginosa kwandisa kakhulu ukulawulwa kwe-corrosion ephakeme kunomthamo wamanje we-corrosion ephakeme kakhulu. ukuthi i-P. aeruginosa biofilm inyusa ukugqwala kwendawo okungu-2707 HDSS.Yuan et al29 bathole ukuthi ukugqwala kwamanje kwe-70/30 Cu-Ni alloy kwenyuke ngaphansi kwenselelo ye-P. aeruginosa biofilm. 2707 HDSS kulo msebenzi.Amafilimu e-Aerobic biofilm nawo angase abe nomoya-mpilo omncane ngaphansi kwawo.Ngakho-ke, ukwehluleka ukuphinda kudlule indawo yensimbi ngomoya komoya kungase kube isici esinomthelela ku-MIC kulo msebenzi.
Dickinson et al. I-38 iphakamise ukuthi amazinga okuphendula kwamakhemikhali kanye ne-electrochemical angathinteka ngokuqondile umsebenzi we-metabolic we-bacterial sessile ebusweni besampula kanye nemvelo yemikhiqizo yokugqwala.Njengoba kuboniswe kuMfanekiso 5 kanye neThebula 5, kokubili inombolo yeseli kanye nokuqina kwe-biofilm kwehle ngemva kwezinsuku ze-14. Lokhu kungachazwa ngokunengqondo ukuthi ngemva kwezinsuku ezingu-14 ze-SSsile ngenxa ye-270 ye-HD, iningi lamaseli e-7 afa ku-70 ukuncipha komsoco endaweni engu-2216E noma ukukhishwa kwama-ion ensimbi anobuthi kusukela ku-matrix ye-HDSS engu-2707. Lokhu kuwumkhawulo wokuhlolwa kwenqwaba.
Kulo msebenzi, i-P. aeruginosa biofilm ikhuthaze ukuncipha kwendawo kwe-Cr ne-Fe ngaphansi kwe-biofilm endaweni engu-2707 HDSS (Fig. 6) .Kuthebula lesi-6, ukuncishiswa kwe-Fe ne-Cr kusampula D uma kuqhathaniswa nesampula C, okubonisa ukuthi i-Fe ne-Cr encibilikisiwe okubangelwa i-P. aeruginosa esetshenziswa ngale kwe-biofilm engu-27 yokuqala ye-21 yezinsuku ezingu-27. linganisa izindawo zasolwandle.Iqukethe i-17700 ppm Cl-, eqhathaniswa naleyo etholakala emanzini olwandle emvelo.Ukuba khona kwe-17700 ppm Cl- kwakuyisizathu esiyinhloko sokwehliswa kwe-Cr kumasampula e-abiotic wezinsuku eziyi-7 nezingu-14 ahlaziywa yi-XPS.Uma kuqhathaniswa nesampula ye-aeruginothi engaphansi kwe-disruginolu engaphansi kwe-disruginolu ye-Cr-aeruginolu eningi ku-Cl− ukumelana okuqinile kwe-2707 HDSS ezindaweni eziphilayo.Umfanekiso 9 ubonisa ukuba khona kwe-Cr6+ kwifilimu ye-passivation.Ingase ihileleke ekukhishweni kwe-Cr endaweni yensimbi yi-P. aeruginosa biofilms, njengoba kuphakanyiswe u-Chen no-Clayton.
Ngenxa yokukhula kwebhaktheriya, amanani e-pH aphakathi ngaphambi nangemuva kokutshala ayengu-7.4 kanye no-8.2, ngokulandelana.Ngakho-ke, ngaphansi kwe-P. aeruginosa biofilm, ukugqwala kwe-organic acid mancane amathuba okuba kube nomthelela kulo msebenzi ngenxa ye-pH ephezulu kakhulu endaweni eyinqwaba. 7.5) phakathi nenkathi yokuhlola yezinsuku eziyi-14. Ukwanda kwe-pH endaweni yokujova ngemva kokufukamela kwakungenxa yomsebenzi we-metabolic we-P. aeruginosa futhi kwatholakala ukuthi kunomphumela ofanayo ku-pH uma ingekho imicu yokuhlola.
Njengoba kuboniswe ku-Figure 7, ukujula komgodi okukhulu okubangelwa i-P. aeruginosa biofilm kwakungu-0.69 μm, okwakukhulu kakhulu kunaleyo ye-abiotic medium (0.02 μm).Lokhu kuhambisana nedatha ye-electrochemical echazwe ngenhla.Ukujula komgodi okungu-0.69 μm kuncane izikhathi eziyishumi kune-μ2m inani elifanayo elibikiwe ngaphansi kwe-DSS ye-9.5. idatha ibonisa ukuthi i-2707 HDSS ibonisa ukumelana ne-MIC okungcono kakhulu uma kuqhathaniswa ne-2205 DSS. Lokhu akufanele kusimangaze, njengoba i-2707 HDSS inokuqukethwe kwe-chromium ephakeme, ehlinzeka ngokudlula okuhlala isikhathi eside, ngenxa yesakhiwo sesigaba esinokulinganisela ngaphandle kwe-precipitates yesibili eyingozi, okwenza kube nzima nge-P. aeruginosa ukuthi ihambe futhi iqale ukufiphala kwamaphuzu.
Ekuphetheni, i-MIC pitting itholakale ebusweni be-2707 HDSS ku-P. aeruginosa umhluzi uma kuqhathaniswa nokubhoboza okungenamsebenzi emithonjeni ye-abiotic.Lo msebenzi ubonisa ukuthi i-2707 HDSS inokumelana okungcono kwe-MIC kune-2205 DSS, kodwa ayivikelekile ngokugcwele ku-MIC ngenxa ye-P. aeruginosa biofilm.
Isigqebhezana se-2707 HDSS sinikezwa iSikole Se-Metallurgy sase-Northeastern University (NEU) e-Shenyang, e-China.Ukwakheka okuyisisekelo kwe-2707 HDSS kuboniswa kuThebula 1, elahlaziywa Umnyango Wokuhlaziywa Kwezinto Zokusebenza kanye Nokuhlola we-NEU.Wonke amasampuli aphathwe ku-1180 °C kuya ku-10-SS noma i-1 corroped yokuhlola i-SS ihora le-10. nendawo engaphezulu eveziwe engaphezulu engu-1 cm2 yapholishwa yaba ngu-2000 grit ngephepha le-silicon carbide futhi yaphinde yapholishwa ngokumiswa kwempushana engu-0.05 μm Al2O3. Izinhlangothi nangaphansi kuvikelwe ngopende ongenayo. Ngemva kokoma, ama-specimens ahlanjululwa ngamanzi angcolile ahlanjululwe futhi afakwa inzalo ngo-5vl/vl. bese yomiswa emoyeni ngaphansi kokukhanya kwe-ultraviolet (UV) amahora angu-0.5 ngaphambi kokusetshenziswa.
I-Marine Pseudomonas aeruginosa I-MCCC 1A00099 strain yathengwa e-Xiamen Marine Culture Collection Centre (MCCC), e-China.I-Pseudomonas aeruginosa ikhuliswe ngendlela ye-aerobic ngo-37°C ngamaflasks angu-250 ml kanye no-500 ml wamaseli engilazi e-electrochemical kusetshenziswa i-Marine 2216E Copeology liquid Qingdao, China).Okumaphakathi (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, 0.2, 0.2 SrCl2, 0.2 H. I-0.004 NaSiO3, 0016 NH3, 0016 NH3, 0016 NaH2PO4, 5.0 peptone, 1.0 yeast extract kanye ne-0.1 ferric citrate.Autoclave ku-121 ° C imizuzu engu-20 ngaphambi kwe-inoculation.Bala i-sessile engaphansi kanye ne-hemocytomic cell400meter ye-apulaktomic ye-planktonic ye-planktonic ukukhuliswa.Iqoqo lokuqala lamaseli e-planktonic Pseudomonas aeruginosa ngokushesha ngemva kokujova cishe lalingamaseli angu-106/ml.
Ukuhlolwa kwe-electrochemical kwenziwa kuseli yengilazi ye-electrode yakudala enevolumu ephakathi kuka-500 ml. Ishidi le-platinum kanye ne-calomel electrode egcwele (SCE) kuxhunywe ku-reactor ngama-Luggin capillaries agcwele amabhuloho kasawoti, asebenza njenge-counter and reference electrode, ngokulandelana. I-cm2 yendawo eveziwe yohlangothi olulodwa lwe-electrode esebenzayo.Ngesikhathi sokulinganisa kwe-electrochemical, amasampula abekwe ku-2216E medium futhi agcinwe ekushiseni okungaguquki kwe-incubation (37 °C) endaweni yokugeza yamanzi.OCP, LPR, EIS kanye nedatha ye-polarization enamandla engase isetshenziswe kulinganiswa kusetshenziswa i-Autolab potentiostat (Reference 600s Instruments werecord at USA scan. isilinganiso esingu-0.125 mV s-1 ebangeni lika -5 no-5 mV nge-Eocp kanye nemvamisa yesampula engu-1 Hz.EIS yenziwe nge-sine wave ebangeni lefrikhwensi engu-0.01 kuya ku-10,000 Hz kusetshenziswa i-voltage engu-5 mV esetshenziswayo endaweni enganyakazi i-Eocp. kufinyelelwe.Amajika e-Polarization abe eseqhutshwa kusukela ku--0.2 kuya ku-1.5 V vs. Eocp ngesilinganiso sokuskena esingu-0.166 mV/s.Ukuhlolwa ngakunye kwaphindwa izikhathi ezi-3 nge-P. aeruginosa nangaphandle kwayo.
Izibonelo zokuhlaziywa kwe-metallographic zapholishwa ngomshini ngephepha le-SiC elimanzi elingu-2000 bese zipholishwa ngokuqhubekayo ngempushana engu-0.05 μm Al2O3 yokumiswa okuyimpushana ukuze ibonwe.
Ngemuva kokufukamela, amasampula ahlanzwa izikhathi ezi-3 ngesisombululo se-phosphate-buffered saline (PBS) (pH 7.4 ± 0.2) bese ehlanganiswa ne-2.5% (v/v) glutaraldehyde amahora angu-10 ukulungisa ama-biofilms. Ngemva kwalokho yaphelelwa amanzi ngochungechunge olulinganiselwe (50%, 8, 70%, 50%, 8%, 70% I-95% kanye ne-100% v/v) ye-ethanol ngaphambi kokoma komoya.Ekugcineni, ingaphezulu lesampula lifafazwa ngefilimu yegolide ukuze kuhlinzekwe ukuqhutshwa kokubhekwa kwe-SEM.Izithombe ze-SEM bezigxile ezindaweni ezinamaseli e-P. aeruginosa anyakazayo kakhulu ebusweni besampula ngayinye.Yenza ukuhlaziya i-EDSAcal ukuze uthole izakhi ze-MCL ze-Scanning ze-MCL (LSM 710, Zeiss, Germany) yasetshenziswa ukukala ukujula komgodi.Ukuze kubhekwe imigodi yokugqwala ngaphansi kwe-biofilm, ucezu lokuhlola lwaqale lwahlanzwa ngokwe-Chinese National Standard (CNS) GB/T4334.4-2000 ukuze kukhishwe imikhiqizo yokugqwala kanye ne-biofilm ebusweni besiqephu sokuhlola.
I-X-ray photoelectron spectroscopy (i-XPS, i-ESCALAB250 uhlelo lokuhlaziya indawo, i-Thermo VG, e-USA) ukuhlaziywa kwenziwa kusetshenziswa umthombo we-X-ray we-monochromatic (umugqa we-aluminium Kα ku-1500 eV amandla kanye namandla angu-150 W) phezu kwebanga elibanzi lamandla abophayo 0 ngaphansi kwezimo ezijwayelekile -1350 eV.High-resolution werecord0 i-eV spection yamandla 20 eV. usayizi.
Izibonelo ezifakiwe zisusiwe futhi zahlanjululwa kahle nge-PBS (pH 7.4 ± 0.2) ye-15 s45. Ukuze kubhekwe ukusebenza kwebhaktheriya kwama-biofilms kumasampuli, ama-biofilms angcoliswa kusetshenziswa i-LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, i-Eugene fluent, i-USA) Udayi we-fluorescent we-SYTO-9 kanye nodayi we-fluorescent we-propidium iodide (PI) obomvu. Ngaphansi kwe-CLSM, amachashazi anombala oluhlaza okotshani kanye nobomvu amele amaseli aphilayo nafile, ngokulandelana. Ukuze kungcoliswe, ingxube engu-1 ml equkethe u-3 μl SYTO-9 kanye nesixazululo esingu-3 μl PI yafakwa endaweni emnyama imizuzu engu-20 oC emazingeni okushisa angama-20 oC. amasampula abonwe ngamaza amaza amabili (488 nm kumaseli aphilayo kanye no-559 nm wamaseli afile) kusetshenziswa umshini we-Nikon CLSM (C2 Plus, Nikon, Japan). Ubukhulu be-Biofilm bulinganiswa ngemodi yokuskena engu-3-D.
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