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I-Microbial corrosion (MIC) yingxaki enkulu kumashishini amaninzi kuba inokukhokelela kwilahleko enkulu yezoqoqosho.I-Super duplex steel stainless 2707 (2707 HDSS) isetyenziswa kwiindawo zaselwandle ngenxa yokumelana kwayo neekhemikhali.Nangona kunjalo, ukuchasana kwayo ne-MIC akuboniswanga ngokomfuniselo.Olu phononongo luvavanye ukuziphatha kwe-MIC 2707 HDSS ebangelwa yibhaktheriya ye-aerobic yolwandle i-Pseudomonas aeruginosa.Uhlalutyo lwe-Electrochemical lubonise ukuba phambi kwe-Pseudomonas aeruginosa biofilm kwi-medium ye-2216E, amandla okutshatyalaliswa atshintshile ngokufanelekileyo, kwaye ukuxinwa kwe-corrosion kwanda.Iziphumo zohlalutyo lwe-X-ray photoelectron spectroscopy (XPS) lubonise ukuhla komxholo we-Cr kumgangatho wesampulu phantsi kwe-biofilm.Uhlalutyo lwemifanekiso yomngxuma lubonise ukuba i-Pseudomonas aeruginosa biofilms ivelise ubunzulu bomgodi obuyi-0.69 µm emva kweentsuku ezili-14 zenkcubeko.Nangona oku kuncinci, kubonisa ukuba i-2707 HDSS ayikhuselekanga ngokupheleleyo kwimiphumo ye-P. aeruginosa biofilms kwi-MIC.
I-Duplex insimbi engenasici (i-DSS) isetyenziswa ngokubanzi kumashishini ahlukeneyo ngenxa yokudibanisa okugqibeleleyo kweempawu ezibalaseleyo zoomatshini kunye nokumelana nokubola1,2.Nangona kunjalo, i-pitting yendawo isengenzeka, enokuthi ichaphazele ingqibelelo yale ntsimbi 3, 4.I-DSS ayikhuselwanga kwi-corrosion ye-microbial (MIC)5,6.Nangona uluhlu lwesicelo se-DSS lubanzi kakhulu, kusekho iindawo apho ukuxhatshazwa kwe-DSS akwanele ukusetyenziswa kwexesha elide.Oku kuthetha ukuba kufuneka izixhobo ezibiza kakhulu ezinokumelana nomhlwa.UJeon et al.7 wafumanisa ukuba nentsimbi ye-duplex egqwesileyo (SDSS) inezithintelo ezithile malunga nokumelana nokubola.Ke ngoko, kukho imfuneko yeentsimbi ze-super duplex stainless (HDSS) ezinokumelana nokonakala okuphezulu kwizicelo ezithile.Oku kwakhokelela ekuphuhlisweni kwe-HDSS ene-alloyed kakhulu.
Ukuxhatshazwa kwe-corrosion ye-DSS kunqunywe ngumlinganiselo we-α-phase ukuya kwi-γ-isigaba kunye neendawo ezichithwe kwi-Cr, i-Mo kunye ne-W ecaleni kwezigaba zesibini8,9,10.I-HDSS iqulethe umxholo ophezulu we-Cr, i-Mo kunye ne-N11, enika ukuchasana kwe-corrosion egqwesileyo kunye nexabiso eliphezulu (45-50) ixabiso elilinganayo lokumelana ne-pitting (PREN), echazwa yi-wt.% Cr + 3.3 (wt.% Mo + 0, 5 wt % W) + 16 wt%.N12.Ukuxhatshazwa kwayo okugqwesileyo kuxhomekeke ekubunjweni kokulinganisela okuqulethe malunga ne-50% ye-ferritic (α) kunye ne-50% ye-austenitic (γ) izigaba.I-HDSS iye yaphucula iipropati zoomatshini kunye nokumelana okuphezulu kweklorini xa kuthelekiswa ne-DSS13 eqhelekileyo.Iimpawu zokubola kweekhemikhali.Ukuphuculwa kokumelana nomhlwa kwandisa ukusetyenziswa kwe-HDSS kwiindawo ezinobundlongondlongo zekloride ezifana neendawo ezihlala elwandle.
I-MIC yingxaki ebalulekileyo kumashishini amaninzi, kuquka i-oyile negesi kunye nonikezelo lwamanzi14.I-MIC yenza i-20% yawo wonke umonakalo owenziwe ngumhlwa15.I-MIC yi-bioelectrochemical corrosion enokubonwa kwiindawo ezininzi16.Ukuqulunqwa kwe-biofilms kwiindawo zetsimbi kutshintsha iimeko ze-electrochemical kwaye ngaloo ndlela kuphembelela inkqubo yokubola.Kuyamkelwa ngokubanzi ukuba i-MIC corrosion ibangelwa yi-biofilms14.Iimicroorganisms ze-Electrogenic zitya iintsimbi ukuze zifumane amandla okuphila17.Uphononongo lwakutsha nje lwe-MIC lubonise ukuba i-EET (ukudluliselwa kwe-electron yangaphandle) yinto ethintelayo ye-MIC eyenziwa zii-electrogenic microorganisms.U-Zhang et al.18 ubonise ukuba abalamli be-electron bakhawulezisa ukudluliselwa kwe-electron phakathi kweeseli ze-Desulfovibrio vulgaris sessile kunye ne-304 yensimbi engenasici, okukhokelela kuhlaselo olubi kakhulu lwe-MIC.UAnning et al.19 kunye noWenzlaff et al.I-20 ibonise ukuba i-biofilms ye-corrosive sulfate-reducing bacteria (SRBs) inokufunxa ii-electron ngokuthe ngqo kwii-substrates zetsimbi, okukhokelela kwi-pitting enzima.
I-DSS yaziwa ukuba ichaphazeleka kwi-MIC kumajelo eendaba aqukethe ii-SRBs, iibhaktheriya zokunciphisa isinyithi (IRBs), njl.Ezi bhaktheriya zibangela i-pitting yendawo ebusweni be-DSS phantsi kwe-biofilm22,23.Ngokungafaniyo ne-DSS, kuncinci okwaziwayo malunga ne-MIC HDSS24.
I-Pseudomonas aeruginosa yintsholongwane ye-Gram-negative, eshukumayo, emile okwentonga esasazwe ngokubanzi kwindalo25.I-Pseudomonas aeruginosa nayo i-microbiota ephambili ejongene ne-MIC yensimbi kwindawo yolwandle26.Iintlobo ze-Pseudomonas zibandakanyeka ngokuthe ngqo kwiinkqubo ze-corrosion kwaye zibonwa njenge-colonizers yokuqala ngexesha lokuqulunqwa kwe-biofilm27.UMahat et al.28 kunye Yuan et al.I-29 ibonise ukuba i-Pseudomonas aeruginosa ithambekele ekunyuseni izinga lokubola kwentsimbi epholileyo kunye ne-alloys kwiindawo ezihlala emanzini.
Injongo ephambili yalo msebenzi kukufunda iimpawu ze-MIC ze-2707 HDSS ezibangelwa ibhaktheriya ye-aerobic yolwandle i-Pseudomonas aeruginosa isebenzisa iindlela ze-electrochemical, iindlela zokuhlalutya umphezulu kunye nohlalutyo lwemveliso yokubola.Izifundo ze-Electrochemical ezibandakanya amandla esekethe evulekileyo (OCP), ukumelana nomgca we-polarization (LPR), i-electrochemical impedance spectroscopy (EIS) kunye ne-polarization eguquguqukayo enokuthi yenziwe ukuze kufundwe ukuziphatha kwe-MIC 2707 HDSS.Uhlalutyo lwe-energy dispersive spectroscopy (EDS) lwenziwa ukuze kufunyanwe izakhi zekhemikhali kwiindawo ezidlekileyo.Ukongezelela, ukuzinza kwefilimu ye-oxide passivation phantsi kweempembelelo zendalo yaselwandle equkethe i-Pseudomonas aeruginosa inqunywe yi-X-ray photoelectron spectroscopy (XPS).Ubunzulu bemingxuma bulinganiswe phantsi kwe-confocal laser scanning microscope (CLSM).
Itheyibhile 1 ibonisa ukubunjwa kweekhemikhali ze-2707 HDSS.Itheyibhile ye-2 ibonisa ukuba i-2707 HDSS ineempawu ezibalaseleyo zoomatshini kunye namandla esivuno se-650 MPa.Kwikhiwane.I-1 ibonisa i-microstructure ye-optical yesisombululo sobushushu esiphathwe nge-2707 HDSS.Iibhendi ezongezelelweyo zezigaba ze-austenitic kunye ne-ferritic ngaphandle kwezigaba zesibini zingabonwa kwi-microstructure equkethe malunga ne-50% ye-austenitic kunye ne-50% ye-ferritic phases.
Kwikhiwane.I-2a ibonisa amandla esekethe evulekileyo (Eocp) ngokubhekiselele kwixesha lokuvezwa kwe-2707 HDSS kwi-2216E abiotic medium kunye ne-Pseudomonas aeruginosa umhluzi weentsuku ze-14 kwi-37 ° C.Kwafunyaniswa ukuba olona tshintsho luchazwe kakhulu kwi-Eocp lwenzeka kwiiyure ezingama-24 zokuqala.Amaxabiso e-EoCP kuzo zombini iimeko anyuke malunga ne-145 mV (ngokuchasene ne-SCE) malunga neeyure ze-16 kwaye zehla ngokukhawuleza ukuya ku--477 mV (ngokuchasene ne-SCE) kunye -236 mV (ngokuchasene ne-SCE) kwiisampulu ezingezizo zebhayoloji kunye ne-P kwisalamane. SCE) amagqabi epatina, ngokulandelanayo.Emva kweeyure ze-24, ixabiso le-Eocp le-Pseudomonas aeruginosa 2707 HDSS lahlala lizinzile kwi--228 mV (xa kuthelekiswa ne-SCE), ngelixa ixabiso elihambelanayo lesampula engeyiyo yebhayoloji lalimalunga ne-442 mV (xa kuthelekiswa ne-SCE).I-Eocp kubukho bePseudomonas aeruginosa yayiphantsi kakhulu.
Uvavanyo lwe-Electrochemical yeesampuli ze-2707 HDSS kwimidiya ye-abiotic kunye ne-Pseudomonas aeruginosa broth kwi-37 ° C:
(a) Utshintsho kwi-Eocp kunye nexesha lokuvezwa, (b) igophe lepolarization ngosuku lwe-14, (c) utshintsho kwi-Rp kunye nexesha lokuvezwa, (d) utshintsho kwi-corr kunye nexesha lokuvezwa.
Itheyibhile 3 ibonisa iiparamitha ze-electrochemical corrosion ye-2707 HDSS iisampulu ezivezwe kwi-abiotic kunye ne-P. aeruginosa yeendaba ezifakwe kwi-inoculated kwithuba leentsuku ze-14.I-Tangential extrapolation ye-anodic kunye ne-cathodic curves ukuya kwindawo ye-intersection ivumela ukumiselwa kwe-corrosion current density (icorr), i-corrosion potential (Ecorr) kunye ne-Tafel slope (βα kunye ne-βc) ngokweendlela eziqhelekileyo30,31.
Njengoko kuboniswe kwi-Figure 2b, ukunyuka okuphezulu kwe-P. aeruginosa kubangele ukwanda kwe-Ecorr xa kuthelekiswa ne-abiotic curve.Ixabiso le-icorr lesampulu equlethe i-Pseudomonas aeruginosa, ngokomlinganiselo wezinga lokubola, linyuke laya kutsho kwi-0.328 µA cm-2, eliphindwe kane kunelo lesampulu engeyoyebhayoloji (0.087 µA cm-2).
I-LPR yindlela yakudala ye-electrochemical yohlalutyo olungonakalisi lokutya.Ikwasetyenziselwa ukufunda i-MIC32.Kwikhiwane.I-2c ibonisa utshintsho kwi-polarization resistance (Rp) ngokuxhomekeke kwixesha lokuvezwa.Ixabiso eliphezulu le-Rp lithetha ukuthotywa okuncinci.Kwiiyure ezingama-24 zokuqala, i-Rp 2707 HDSS yanda kwi-1955 kΩ cm2 kwimizekelo engeyoyebhayoloji kunye ne-1429 kΩ cm2 yesampulu zePseudomonas aeruginosa.Umzobo 2c ubonisa ukuba ixabiso le-Rp lehle ngokukhawuleza emva kosuku olunye kwaye lahlala lingaguqukanga kwiintsuku ze-13 ezilandelayo.Ixabiso le-Rp lovavanyo lovavanyo lwe-Pseudomonas aeruginosa limalunga ne-40 kΩ cm2, elingaphantsi kakhulu kunexabiso le-450 kΩ cm2 kumzekelo wovavanyo olungelulo lwebhayoloji.
Ixabiso le-icorr lilingana nezinga lokutya okufanayo.Ixabiso layo lingabalwa kule equation yeStern-Giri ilandelayo:
Ngokutsho kukaZoe et al.33 ithambeka le-Tafel B lithathwe njengexabiso eliqhelekileyo le-26 mV/dec kulo msebenzi.Kwikhiwane.I-2d ibonisa ukuba i-icorr ye-2707 ye-abiotic strain yahlala izinzile, ngelixa i-icorr yebhendi ye-Pseudomonas aeruginosa iguquguquka ngamandla ngokutsiba okukhulu emva kweeyure ezingama-24 zokuqala.Ixabiso le-icorr lesampula yovavanyo lwe-Pseudomonas aeruginosa yayingumyalelo wobukhulu obuphezulu kunolawulo olungelulo lwebhayoloji.Lo mkhwa uhambelana neziphumo zokumelana ne-polarization.
I-EIS yenye indlela engonakalisi esetyenziselwa ukubonakalisa ukuphendulwa kwe-electrochemical kwi-corrosion interface34.I-Impedance spectra kunye nokubalwa kwe-capacitance ye-strips evezwe kwimidiya ye-abiotic kunye nezisombululo ze-Pseudomonas aeruginosa, i-Rb yinkcaso ye-passive / biofilm eyenziwe phezu komphezulu we-strip, i-Rct yi-resistance transfer transfer, i-Cdl ngumbane ophindwe kabini.) kunye neeparamitha ze-QCPE zesigaba esiqhubekayo (CPE).Ezi parameters zahlaziywa ngakumbi ngokuthelekisa idatha kunye nemodeli yesekethe yombane elinganayo (EEC).
Kwikhiwane.I-3 ibonisa iiploti zeNyquist eziqhelekileyo (a kunye ne-b) kunye neeploti zeBode (a' kunye ne-b') ze-2707 zesampulu ze-HDSS kwimidiya ye-abiotic kunye ne-Pseudomonas aeruginosa umhluzi ngamaxesha ahlukeneyo okufukamela.Ubukho bePseudomonas aeruginosa, ububanzi beNyquist loop buyancipha.Isakhiwo seBode (Umfanekiso 3b ') ubonisa ukwanda kwe-impedance epheleleyo.Ulwazi malunga nexesha lokuphumla elingaguqukiyo linokufumaneka kwi-phase maxima.Kwikhiwane.I-4 ibonisa izakhiwo ezibonakalayo kunye ne-EEC ehambelanayo esekelwe kwi-single-layer (a) kunye ne-two-layer (b).I-CPE yaziswa kwimodeli ye-EEC.Ukwamkelwa kwayo kunye nokuphazamiseka kubonakaliswa ngolu hlobo lulandelayo:
Iimodeli ezimbini zomzimba kunye neesekethe ezilinganayo zokulinganisa i-2707 HDSS coupon impedance spectrum:
Apho u-Y0 bubukhulu be-CPE, j linani lentelekelelo okanye (−1)1/2, ω yi-angular frequency, kwaye n yi-CPE factor factor engaphantsi kwe-135.I-inversion yokumelana nokudluliselwa kwentlawulo (okt 1 / Rct) ihambelana nezinga lokubola.Ixabiso eliphantsi leRct lithetha izinga eliphezulu lokutya27.Emva kweentsuku ze-14 zokufukamela, i-Rct yesampula yovavanyo lwe-Pseudomonas aeruginosa ifikelele kwi-32 kΩ cm2, engaphantsi kakhulu kwe-489 kΩ cm2 yesampula yovavanyo lwe-non-biological (Itheyibhile 4).
Imifanekiso ye-CLSM kunye nemifanekiso ye-SEM kwifig.I-5 ibonisa ngokucacileyo ukuba i-biofilm coverage ebusweni be-HDSS isampuli ye-2707 yayixinene kakhulu emva kweentsuku ze-7.Nangona kunjalo, emva kweentsuku ezili-14 i-biofilm iyagquma kwaye yavela kwaye ezinye iiseli ezifileyo zavela.Itheyibhile 5 ibonisa ubukhulu be-biofilm ye-2707 HDSS iisampulu emva kwe-7 kunye neentsuku ze-14 zokuvezwa kwi-Pseudomonas aeruginosa.Ubuninzi bebhayofilm ubukhulu butshintshile ukusuka kwi-23.4 µm emva kweentsuku ezisi-7 ukuya kwi-18.9 µm emva kweentsuku ezili-14.Umndilili wobunzima bebhayofilm nawo ubuqinisekisile lo mkhwa.Yehla ukusuka kwi-22.2 ± 0.7 μm emva kweentsuku ezi-7 ukuya kwi-17.8 ± 1.0 μm emva kweentsuku ezili-14.
(a) Umfanekiso we-3-D CLSM ngeentsuku ezisi-7, (b) umfanekiso we-3-D CLSM ngeentsuku ezili-14, (c) umfanekiso we-SEM ngeentsuku ezisi-7, kunye (d) nomfanekiso we-SEM ngeentsuku ezili-14.
I-EMF iveze izinto zekhemikhali kwi-biofilm kunye neemveliso zokubola kwiisampulu ezivezwe kwi-Pseudomonas aeruginosa kangangeentsuku ezili-14.Kwikhiwane.Umzobo we-6 ubonisa ukuba umxholo we-C, N, O, P kwi-biofilm kunye neemveliso ze-corrosion ziphezulu kakhulu kunentsimbi ecocekileyo, ekubeni ezi zinto zidibene ne-biofilm kunye ne-metabolites yayo.Ii-Microorganisms zifuna kuphela umkhondo we-Cr kunye ne-Fe.Umxholo ophezulu we-Cr kunye ne-Fe kwi-biofilm kunye nemveliso ye-corrosion kumphezulu wesampuli ibonisa ukulahlekelwa kwezinto kwi-matrix yensimbi ngenxa ye-corrosion.
Emva kweentsuku ezili-14, imingxuma ene-P. aeruginosa nangaphandle kwayo yabonwa phakathi kwe-2216E.Ngaphambi kokufukanyelwa, ubuso beesampuli bubushelelezi kwaye bungenaziphene (umzobo 7a).Emva kokufakwa kunye nokususwa kwe-biofilm kunye nemveliso ye-corrosion, imingxuma enzulu kakhulu kumphezulu wesampuli ihlolwe kusetyenziswa i-CLSM, njengoko kuboniswe kwi-Fig. 7b kunye ne-c.Akukho mgodi ucacileyo ufunyenwe kumphezulu wolawulo olungelulo lwebhayoloji (obona bukhulu bomngxuma ubunzulu yi-0.02 µm).Obona bukhulu bomngxuma ubunzulu obubangelwa yi-Pseudomonas aeruginosa yaba yi-0.52 µm emva kweentsuku ezisi-7 kunye ne-0.69 µm emva kweentsuku ezili-14, ngokusekwe kumndilili wobunzulu bomngxuma obuphezulu ukusuka kwiisampulu ezi-3 (i-10 ubunzulu bomgodi obuphezulu bakhethwa kwisampulu nganye) kwaye bafikelela kwi-0. 42 ± 0.12 µm .kunye ne-0.52 ± 0.15 µm, ngokulandelelanayo (iThebhile 5).Ezi xabiso zobunzulu be-dimple zincinci kodwa zibalulekile.
(a) phambi kokuba sesichengeni;(b) iintsuku ezili-14 kwindawo yendalo ephilayo;(c) Iintsuku ezili-14 kumhluzi we-P. aeruginosa.
Kwikhiwane.Itheyibhile 8 ibonisa i-XPS spectra yemigangatho eyahlukeneyo yeesampulu, kwaye ikhemistri ehlalutyiweyo kwindawo nganye ishwankathelwa kwiThebhile 6. KwiThebhile 6, iipesenti ze-athomu ze-Fe kunye ne-Cr zaziphantsi kakhulu kubukho be-P. aeruginosa (iisampulu A kunye ne-B ) kunakwimigca yolawulo engeyiyo eyebhayoloji.(iisampulu C kunye no-D).Kwisampulu ye-Pseudomonas aeruginosa, i-Cr 2p yenqanaba le-spectral curve engundoqo ifakwe kumacandelo amane aphezulu kunye namandla okubopha (BE) ye-574.4, 576.6, 578.3 kunye ne-586.8 eV, eyabelwa i-Cr, i-Cr2O3, i-CR (O3) kunye ne-CR (O3) 3, ngokulandelanayo (Umfanekiso 9a kunye b).Kwiisampuli ze-nonbiological, i-spectra yenqanaba eliphambili le-Cr 2p kwiiFig.I-9c kunye ne-d iqulethe iincopho ezimbini eziphambili ze-Cr (BE 573.80 eV) kunye ne-Cr2O3 (BE 575.90 eV), ngokulandelanayo.Owona mahluko ubalaseleyo phakathi kwekhuphoni ye-abiotic kunye nekhuphoni ye-P. aeruginosa yayibubukho be-Cr6 + kunye neqhezu eliphezulu kakhulu le-Cr (OH) 3 (BE 586.8 eV) phantsi kwe-biofilm.
Imbonakalo ebanzi ye-XPS ye-2707 HDSS iisampulu kwimidiya emibini ye-7 kunye neentsuku ze-14, ngokulandelanayo.
(a) iintsuku ezisi-7 ukuba sesichengeni se-P. aeruginosa, (b) iintsuku ezili-14 ukuba sesichengeni se-P. aeruginosa, (c) iintsuku ezisi-7 ukuba sesichengeni se-abiotic, (d) iintsuku ezili-14 zokuba sesichengeni se-abiotic.
I-HDSS ibonisa umgangatho ophezulu wokumelana nokubola kwiindawo ezininzi.UKim et al.2 wabika ukuba i-HDSS UNS S32707 ichongiwe njenge-DSS ene-doped kakhulu kunye ne-PREN enkulu kune-45. Ixabiso le-PREN le-HDSS isampuli ye-2707 kulo msebenzi yayingu-49. Oku kungenxa yomxholo ophezulu we-Cr kunye namazinga aphezulu e-Mo kunye I-Ni, eluncedo kwiindawo ezine-acidic kunye neendawo ezinomxholo ophezulu we-chlorides.Ukongezelela, ukubunjwa okunokulinganisela kunye ne-microstructure engenasiphako inikezela ukuzinza kwesakhiwo kunye nokumelana nokubola.Nangona ukuchasana kweekhemikhali okugqwesileyo, idatha yovavanyo kulo msebenzi ibonisa ukuba i-2707 HDSS ayikhuselekanga ngokupheleleyo kwi-Pseudomonas aeruginosa biofilm MICs.
Iziphumo ze-Electrochemical zibonise ukuba izinga lokubola kwe-2707 HDSS kwi-Pseudomonas aeruginosa broth yanda kakhulu emva kweentsuku ze-14 xa kuthelekiswa nendawo engeyiyo yezinto eziphilayo.Kwi-Figure 2a, ukuncipha kwe-Eocp kwabonwa kokubili kwi-abiotic medium kunye ne-P. aeruginosa umhluzi kwiiyure ezingama-24 zokuqala.Emva koko, i-biofilm igqiba ukugubungela umphezulu wesampuli kwaye i-Eocp izinzile.Nangona kunjalo, inqanaba le-biotic Eocp laliphezulu kakhulu kunenqanaba le-abiotic Eocp.Kukho izizathu zokukholelwa ukuba lo mahluko unxulumene nokusekwa kwe-P. aeruginosa biofilms.Kwikhiwane.I-2g, ixabiso le-icorr le-2707 HDSS lifikelele kwi-0.627 µA cm-2 phambi kwe-Pseudomonas aeruginosa, i-odolo ye-magnitude ephezulu kune-non-biological control (0.063 µA cm-2), ehambelana ne-Rct ixabiso elilinganiswe nge-EIS.Ngeentsuku ezimbalwa zokuqala, ixabiso le-impedance kwi-P. aeruginosa broth liye lanyuka ngenxa yokufakelwa kweeseli ze-P. aeruginosa kunye nokwakhiwa kwe-biofilm.Nangona kunjalo, i-impedance iyancipha xa i-biofilm igubungela ngokupheleleyo umphezulu wesampulu.Uluhlu olukhuselayo luhlaselwa ngokuyinhloko ngenxa yokubunjwa kwe-biofilm kunye ne-biofilm metabolites.Ke ngoko, ukuxhathisa ukubola kuyehla ngokuhamba kwexesha, kwaye iidiphozithi zePseudomonas aeruginosa zibangela ukubola kwendawo.Iindlela zokusingqongileyo ze-abiotic zahlukile.Ukuxhatshazwa kwe-corrosion ye-non-biological control yayiphezulu kakhulu kunexabiso elihambelanayo leesampuli ezivezwe kwi-Pseudomonas aeruginosa broth.Ukongezelela, kwiisampuli ze-abiotic, ixabiso le-Rct 2707 HDSS lifikelele kwi-489 kΩ cm2 ngosuku lwe-14, eliphindwe ka-15 ngaphezu kobukho be-Pseudomonas aeruginosa (32 kΩ cm2).Ngaloo ndlela, i-2707 HDSS inokumelana ne-corrosion egqwesileyo kwindawo eyinyumba, kodwa ayikhuselwanga kuhlaselo lwe-MIC yi-Pseudomonas aeruginosa biofilm.
Ezi ziphumo zinokujongwa kwakhona kwi-polarization curves kwiFig.2b.I-Anodic branching idibene ne-Pseudomonas aeruginosa ukubunjwa kwe-biofilm kunye neempendulo ze-oxidation zetsimbi.Ngelo xesha, ukusabela kwe-cathodic kukunciphisa i-oxygen.Ubukho be-P. aeruginosa bandise kakhulu ubuninzi be-corrosion current, obumalunga nomyalelo wobukhulu obuphezulu kunolawulo lwe-abiotic.Oku kubonise ukuba i-Pseudomonas aeruginosa biofilm iphucule i-corrosion yendawo ye-2707 HDSS.U-Yuan et al.29 wafumanisa ukuba ubuninzi be-corrosion yangoku ye-70/30 Cu-Ni ingxubevange yonyuswa yi-Pseudomonas aeruginosa biofilm.Oku kunokuba ngenxa ye-biocatalysis yokunciphisa i-oksijini nge-Pseudomonas aeruginosa biofilm.Olu qwalaselo lunokucacisa kwakhona i-MIC 2707 HDSS kulo msebenzi.Iifilim zeAerobic nazo zinokunciphisa umxholo weoksijini ongaphantsi kwazo.Ngaloo ndlela, ukwala ukubuyisela i-metal surface nge-oksijini kunokuba yinto ebangela i-MIC kulo msebenzi.
UDickinson et al.38 icebise ukuba ireyithi yeekhemikhali kunye ne-electrochemical reactions ngokuthe ngqo ixhomekeke kwimisebenzi ye-metabolic yebhaktheriya encanyathiselwe kumphezulu wesampulu kunye nohlobo lweemveliso zokubola.Njengoko kuboniswe kwi-Figure 5 kunye neThebhile 5, inani leeseli kunye ne-biofilm ubukhulu behla emva kweentsuku ze-14.Oku kunokuchazwa ngokufanelekileyo kukuba emva kweentsuku ezili-14 uninzi lweeseli ezi-ankile kumphezulu we-2707 HDSS zafa ngenxa yokuncipha kwezondlo kwi-2216E medium okanye ukukhutshwa kwee-ion zesinyithi eziyityhefu kwi-2707 HDSS matrix.Lo ngumda wemifuniselo yebhetshi.
Kulo msebenzi, i-Pseudomonas aeruginosa biofilm ikhuthaze ukuchithwa kwendawo ye-Cr kunye ne-Fe phantsi kwe-biofilm ebusweni be-2707 HDSS (Umfanekiso 6).KwiThebhile 6, i-Fe kunye ne-Cr yehla kwisampula D xa kuthelekiswa nesampuli C, ebonisa ukuba i-Fe kunye ne-Cr yokuchithwa okubangelwa yi-P. aeruginosa biofilm igcinwe emva kweentsuku zokuqala ze-7.Imo engqongileyo ye-2216E isetyenziselwa ukulinganisa imeko-bume yaselwandle.Iqulethe i-17700 ppm Cl-, ethelekiseka nomxholo wayo kumanzi endalo olwandle.Ubukho be-17700 ppm Cl- yayisisizathu esiyintloko sokuhla kwe-Cr kwiintsuku ze-7 kunye ne-14-day non-biological samples ezihlalutywe yi-XPS.Xa kuthelekiswa nesampulu yovavanyo lwe-Pseudomonas aeruginosa, ukuchithwa kwe-Cr kwisampulu yovavanyo lwe-abiotic kuncinci kakhulu ngenxa yokuchasana okunamandla kwe-2707 HDSS kwi-chlorine kwindawo ye-abiotic.Kwikhiwane.I-9 ibonisa ubukho be-Cr6 + kwifilimu edlulayo.Oku kunokuhambelana nokususwa kwe-Cr kwiindawo zensimbi nge-P. aeruginosa biofilms, njengoko kucetyiswe nguChen noClayton39.
Ngenxa yokukhula kwebhaktheriya, ixabiso le-pH eliphakathi ngaphambi nasemva kokufukanyelwa laliyi-7.4 kunye ne-8.2, ngokulandelelanayo.Ngaloo ndlela, ukubola kwe-organic acids akunakwenzeka ukuba negalelo kulo msebenzi phantsi kwe-P. aeruginosa biofilms ngenxa ye-pH ephezulu kwi-bulk medium.I-pH ye-non-biological control medium ayizange itshintshe kakhulu (ukusuka kwi-7.4 yokuqala ukuya kwi-7.5 yokugqibela) ngexesha lovavanyo lweentsuku ezili-14.Ukunyuka kwe-pH kwi-inoculum medium emva kokufakwa kwe-incubation kuhambelana nomsebenzi we-metabolic we-Pseudomonas aeruginosa, kwaye umphumo ofanayo kwi-pH ufunyenwe ngokungabikho komcu wokuvavanya.
Njengoko kubonisiwe kwifig.7, obona bukhulu bomngxuma ubunzulu obubangelwa yi-Pseudomonas aeruginosa biofilm yayiyi-0.69 µm, engaphezulu kakhulu kune-abiotic medium (0.02 µm).Oku kuvumelana nedatha ye-electrochemical engentla.Phantsi kweemeko ezifanayo, ubunzulu bomgodi we-0.69 µm bungaphezulu komphinda-phindwe kashumi omncinci kune-9.5 µm ixabiso elichazwe ku-2205 DSS40.Ezi datha zibonisa ukuba i-2707 HDSS ibonisa ukuchasana okungcono kwi-MIC kune-2205 DSS.Oku akumangalisi kuba i-2707 HDSS inezinga eliphezulu le-Cr, elivumela ukudlula ixesha elide, yenza i-Pseudomonas aeruginosa ibe nzima ukuyikhupha, kwaye iqala inkqubo ngaphandle kwemvula yesibini eyingozi i-Pitting41.
Ukuqukumbela, i-MIC pitting yafunyanwa kwi-2707 HDSS surfaces kwi-Pseudomonas aeruginosa broth, ngelixa i-pitting yayingenamsebenzi kwimidiya ye-abiotic.Lo msebenzi ubonisa ukuba i-2707 HDSS inokuchasana okungcono kwi-MIC kune-2205 DSS, kodwa ayikhuselekanga ngokupheleleyo kwi-MIC ngenxa ye-Pseudomonas aeruginosa biofilm.Ezi ziphumo zinceda ekukhetheni iintsimbi eziziintsimbi ezifanelekileyo kunye neminyaka elindelekileyo yokuphila kwendalo yaselwandle.
Iisampulu ze-HDSS ze-2707 zanikezelwa yiSikolo seMetallurgy, iYunivesithi yaseNortheastern (NEU), iShenyang, eChina.Ukuqulunqwa okusisiseko kwe-2707 HDSS kuboniswe kwiThebhile 1, eyahlalutywa liSebe loHlalutyo lweMathiriyeli kunye noVavanyo lweYunivesithi yaseMntla-mpuma.Zonke iisampuli zaphathwa isisombululo esiqinileyo kwi-1180 ° C ngeyure eli-1.Phambi kovavanyo lomhlwa, intsimbi ye-2707 HDSS enendawo eveziweyo eyi-1 cm2 yapolishwa yaya kutsho ku-2000 grit ngesilicon carbide sandpaper yaze yaphuculwa ngakumbi nge-0.05 µm Al2O3 powder slurry.Amacala kunye nezantsi zikhuselwe ngepeyinti ye-inert.Emva kokumisa, iisampulu zihlanjwe ngamanzi angcolileyo ahlambulukileyo kwaye zihlanjululwe nge-75% (v / v) ye-ethanol ye-0.5 h.Emva koko zomiswa emoyeni phantsi kokukhanya kwe-ultraviolet (UV) i-0.5 h phambi kokusetyenziswa.
Ubunzima baselwandle i-Pseudomonas aeruginosa MCCC 1A00099 yathengwa kwi-Xiamen Marine Culture Collection (MCCC), e-China.I-Marine 2216E liquid medium (Qingdao Hope Biotechnology Co., Ltd., Qingdao, China) yayisetyenziselwa ukulima iPseudomonas aeruginosa kwiiflasks ezingama-250 ml kunye ne-500 ml yeeseli zeglasi ye-electrochemical phantsi kweemeko ze-aerobic kwi-37 ° C.Iphakathi iqulethe (g / l): 19.45 I-NACCL2, 3.24 I-NASIO4I-1.0 yeast extract kunye ne-0.1 citrate yentsimbi.I-Autoclave kwi-121 ° C ye-20 min ngaphambi kokugonywa.I-Sessile kunye neeseli zeplanktonic zibalwe phantsi kwe-microscope yokukhanya usebenzisa i-hemocytometer kwi-400x yokukhulisa.Ukuxinwa kokuqala kweeseli zeplanktonic P. aeruginosa ngokukhawuleza emva kokugonywa kwakumalunga neeseli ze-106 / mL.
Iimvavanyo ze-Electrochemical zenziwa kwi-classic yeglasi ye-electrode emithathu kunye nomthamo ophakathi kwe-500 ml.Iphepha leplatinum kunye ne-calomel electrode egcweleyo (SCE) yaxhunywa kwi-reactor ngokusebenzisa i-Luggin capillary egcwele ibhuloho yetyuwa kwaye yasebenza njenge-counter and reference electrode, ngokulandelanayo.Ukudala i-electrode esebenzayo, i-rubber-copper copper ifakwe kwisampuli nganye kwaye ifakwe kwi-epoxy, ishiya malunga ne-1 cm2 yendawo yendawo kwicala elinye kwi-electrode esebenzayo.Ngexesha lokulinganisa i-electrochemical, iisampuli zifakwe kwi-2216E medium kwaye zigcinwe kwiqondo lokushisa eliqhubekayo (37 ° C) kwindawo yokuhlambela amanzi.I-OCP, i-LPR, i-EIS kunye nedatha ye-polarization enokubakho ilinganiswa kusetyenziswa i-Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA).Iimvavanyo ze-LPR zirekhodwe kwireyithi yokuskena ye-0.125 mV s-1 kwi--5 kunye ne-5 mV uluhlu kunye ne-Eocp kunye ne-sampling rate ye-1 Hz.I-EIS yenziwa kwindawo ezinzileyo ye-Eocp isebenzisa i-voltage esetyenzisiweyo ye-5 mV ene-sinusoid phezu koluhlu lwamaza kwi-0.01 ukuya kwi-10,000 Hz.Ngaphambi kokutshayela okunokwenzeka, i-electrodes yayikwimowudi yesekethe evulekileyo kwaze kwaba yilapho i-stable free corrosion potential of 42 yafikelelwa.Nge.Uvavanyo ngalunye luphindwe kathathu kunye nangaphandle kwePseudomonas aeruginosa.
Iisampulu zohlalutyo lwe-metallographic zapolishwa ngomatshini nge-2000 grit emanzi yephepha le-SiC kwaye emva koko yapolishwa nge-0.05 µm Al2O3 yomgubo we-slurry ukuze ijongwe ngamehlo.Uhlalutyo lwe-metallographic lwenziwa kusetyenziswa i-microscope ebonakalayo.Isampuli yabhalwa nge-10 wt% isisombululo se-potassium hydroxide43.
Emva kokufukanyelwa, hlamba amaxesha e-3 nge-phosphate buffered saline (PBS) (pH 7.4 ± 0.2) uze ulungise nge-2.5% (v/v) glutaraldehyde iiyure ezili-10 ukulungisa i-biofilm.Ukuchithwa okulandelayo kunye ne-ethanol kuluhlu olunyathelweyo (50%, 60%, 70%, 80%, 90%, 95% kunye ne-100% ngevolumu) ngaphambi kokumisa umoya.Ekugqibeleni, ifilimu yegolide yachaphazelwa kumphezulu wesampulu ukubonelela nge-conductivity yokujongwa kwe-SEM44.Imifanekiso ye-SEM igxininise kwindawo eneeseli ze-P. aeruginosa ezisekiweyo kumphezulu wesampuli nganye.Uhlalutyo lwe-EMF lwenziwa ukukhangela izinto zekhemikhali.Ukulinganisa ubunzulu bomngxuma, kwasetyenziswa imakroskopu yeZeiss confocal laser scanning (CLSM) (LSM 710, Zeiss, Germany).Ukuqwalasela imigodi ye-corrosion phantsi kwe-biofilm, isampuli yovavanyo yaqala ukucocwa ngokwe-Chinese National Standard (CNS) GB/T4334.4-2000 ukususa iimveliso ze-corrosion kunye ne-biofilm kumphezulu wesampuli yovavanyo.
I-X-ray photoelectron spectroscopy (XPS, ESCALAB250 Surface Analysis System, Thermo VG, USA) uhlalutyo usebenzisa umthombo we-X-ray we-monochromatic (umgca we-Al Kα onamandla e-1500 eV kunye namandla e-150 W) kuluhlu olubanzi lwamandla okubopha. 0 ngaphantsi kweemeko ezisemgangathweni -1350 eV.Rekhoda i-spectra yesisombululo esiphezulu usebenzisa i-50 eV pass energy kunye ne-0.2 eV ubungakanani besinyathelo.
Susa isampuli efukanyiweyo kwaye uyihlambe ngobunono nge-PBS (pH 7.4 ± 0.2) kwi-15 s45.Ukuqwalasela ukusebenza kwebhaktheriya ye-biofilm kwisampulu, i-biofilm yachithwa kusetyenziswa i-LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA).Ikhithi iqulethe iidayi ezimbini ze-fluorescent: I-SYTO-9 ye-fluorescent eluhlaza kunye ne-propidium iodide (PI) idayi ebomvu ye-fluorescent.Kwi-CLSM, amachaphaza aluhlaza kunye nebomvu e-fluorescent amele iiseli eziphilayo nezifileyo, ngokulandelanayo.Ukucoca, fakela i-1 ml yomxube oqulethe i-3 µl ye-SYTO-9 kunye ne-3 µl yesisombululo se-PI kwiqondo lobushushu begumbi (23°C) ebumnyameni imizuzu engama-20.Emva koko, iisampulu ezinamabala zajongwa kumaza amabini (488 nm yeeseli eziphilayo kunye ne-559 nm yeeseli ezifileyo) kusetyenziswa i-Nikon CLSM apparatus (C2 Plus, Nikon, Japan).Ukulinganisa ubukhulu bebhayofilm kwimowudi yokuskena ye-3-D.
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ULuo H., i-Dong KF, i-Li HG kunye no-Xiao K. Ukuziphatha kwe-Electrochemical ye-2205 i-duplex yensimbi engenasici kwizisombululo ze-alkaline kwiimpawu ezahlukeneyo ze-pH phambi kwe-chloride.electrochemistry.Ijenali.64, 211-220 (2012).
Ixesha lokuposa: Jan-09-2023