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He pilikia koʻikoʻi ka microbial corrosion (MIC) i nā ʻoihana he nui, no ka mea hiki ke alakaʻi i nā poho waiwai nui.Hoʻohana ʻia ʻo Super duplex stainless steel 2707 (2707 HDSS) i nā kaiapuni kai ma muli o kona kūpaʻa kemika maikaʻi loa.Eia naʻe, ʻaʻole i hōʻike ʻia kona kūʻē ʻana iā MIC.Ua nānā kēia haʻawina i ka ʻano o MIC 2707 HDSS i hoʻokumu ʻia e ka marine aerobic bacterium Pseudomonas aeruginosa.Ua hōʻike ʻo Electrochemical analysis i ke alo o Pseudomonas aeruginosa biofilm i ka 2216E medium, hiki ke hoʻololi maikaʻi i ka hiki ʻana o ka corrosion a me ka piʻi ʻana o ka nui o ka corrosion i kēia manawa.Ua hōʻike ka ʻike ʻana o ka X-ray photoelectron spectroscopy (XPS) i ka emi ʻana o ka ʻike Cr ma ka ʻili o ka hāpana ma lalo o ka biofilm.Hōʻike ka nānā ʻana i nā lua i ka P. aeruginosa biofilm i hana i ka hohonu o ka lua he 0.69 µm i nā lā 14 o ka incubation.ʻOiai heʻuʻuku kēia, e hōʻike anaʻo 2707 HDSSʻaʻole i palekana loa i ka MIC o nā biofilms P. aeruginosa.
Hoʻohana nui ʻia ʻo Duplex stainless steels (DSS) i nā ʻoihana like ʻole ma muli o ka hui maikaʻi ʻana o nā waiwai mechanical maikaʻi loa a me ke kūpaʻa corrosion1,2.Eia nō naʻe, ke kū nei ka lua kūloko a pili i ka pono o kēia kila3,4.ʻAʻole kūpaʻa ʻo DSS i ka microbial corrosion (MIC)5,6.ʻOiai ka laulā o nā noi no DSS, aia nō nā kaiapuni kahi i lawa ʻole ai ke kūpaʻa corrosion o DSS no ka hoʻohana lōʻihi.ʻO ia hoʻi, pono nā mea kūʻai nui me ke kūpaʻa corrosion kiʻekiʻe.Ua ʻike ʻo Jeon et al7 ʻoiai ʻo ka super duplex stainless steels (SDSS) kekahi mau palena i ke ʻano o ka pale ʻana i ka corrosion.No laila, i kekahi mau hihia, koi ʻia nā kila kila kila super duplex (HDSS) me ke kūpaʻa corrosion kiʻekiʻe.Ua alakaʻi kēia i ka hoʻomohala ʻana o ka HDSS i hoʻohui ʻia.
ʻO ka pale ʻana o ka corrosion DSS e pili ana i ka ratio o ka alpha a me ka gamma phase a hoʻopau ʻia ma Cr, Mo a me W māhele 8, 9, 10 e pili ana i ka pae ʻelua.Loaʻa i ka HDSS kahi maʻiʻo kiʻekiʻe o Cr, Mo a me N11, no laila he kūpaʻa maikaʻi maikaʻi loa ia a me kahi waiwai kiʻekiʻe (45-50) o ka helu hoʻohālikelike pitting (PREN) i hoʻoholo ʻia e wt.% Cr + 3.3 (wt.% Mo + 0.5 wt. .%W) + 16% wt.N12.ʻO kona kūpaʻa ʻino maikaʻi e hilinaʻi ʻia i ka haku mele ʻana i loaʻa ma kahi o 50% ferritic (α) a me 50% austenitic (γ).ʻOi aku ka maikaʻi o ka HDSS a me ke kūpaʻa kiʻekiʻe o ka chloride corrosion.Hoʻonui ka pale ʻana i ka corrosion i ka hoʻohana ʻana i ka HDSS ma nā wahi chloride koʻikoʻi e like me nā kaiapuni moana.
He pilikia nui nā MIC ma nā ʻoihana he nui e like me ka ʻoihana aila a me ka ʻenehana a me ka wai14.ʻO MIC ka 20% o nā pōʻino ʻino a pau15.ʻO ka MIC kahi ʻino bioelectrochemical hiki ke ʻike ʻia ma nā wahi he nui.ʻO nā biofilms i hana ʻia ma luna o nā ʻili metala e hoʻololi i nā kūlana electrochemical, a laila pili i ke kaʻina hana ʻino.Manaʻo nui ʻia ʻo ka MIC corrosion ke kumu o nā biofilms.ʻAi nā microorganisms electrogenic i nā metala no ka loaʻa ʻana o ka ikehu e pono ai ke ola17.Ua hōʻike ʻia nā haʻawina MIC hou ʻo EET (extracellular electron transfer) ka helu-palena kumu i ka MIC i hoʻokomo ʻia e nā microorganisms electrogenic.ʻO Zhang et al.Ua hōʻike ʻo 18 i ka hoʻololi ʻana o nā electron ma waena o Desulfovibrio sessificans cell a me 304 stainless steel, e hopena i ka hoʻouka kaua MIC.ʻO Anning et al.19 a me Wenzlaff et al.Ua hōʻike ʻo 20 e hiki i nā biofilms o corrosive sulfate-reducing bacteria (SRBs) hiki ke hoʻopili pololei i nā electrons mai nā substrate metala, e hopena i ka lua nui.
ʻIke ʻia ʻo DSS e hiki ke maʻalahi i ka MIC i loko o ka media i loaʻa nā SRBs, iron-reducing bacteria (IRBs), etc. 21.ʻO kēia mau bacteria ke kumu o ka lua ʻokoʻa ma ka ʻili o DSS ma lalo o nā biofilms22,23.ʻAʻole like me DSS, ʻaʻole ʻike maikaʻi ʻia ka HDSS24 MIC.
ʻO ka Pseudomonas aeruginosa he mea kino Gram-negative, motile, ʻano koʻokoʻo i laha nui ʻia ma ke ʻano25.ʻO Pseudomonas aeruginosa kekahi pūʻulu microbial nui i ka moana kai, e hoʻonui ana i ka nui o ka MIC.Hoʻokomo ikaika ʻia ʻo Pseudomonas i ke kaʻina hana corrosion a ʻike ʻia ʻo ia he colonizer paionia i ka wā o ka hoʻokumu ʻana o biofilm.Mahat et al.28 a ʻo Yuan et al.Ua hōʻike ʻo 29 i ka Pseudomonas aeruginosa e hoʻonui i ka nui o ka corrosion o nā kila māmā a me nā mea hoʻohui i nā kaiaola.
ʻO ka pahuhopu nui o kēia hana ʻo ia ka noiʻi ʻana i nā waiwai o MIC 2707 HDSS i hoʻokumu ʻia e ka marine aerobic bacterium Pseudomonas aeruginosa me ka hoʻohana ʻana i nā ʻano electrochemical, nā ʻano loiloi ʻili a me ka nānā ʻana i nā huahana corrosion.Ua hana ʻia nā haʻawina electrochemical, me ka open circuit potential (OCP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), a me ka dynamic polarization, e aʻo i ke ʻano o ka MIC 2707 HDSS.Ua hoʻokō ʻia ka ikehu dispersive spectrometric analysis (EDS) no ka ʻike ʻana i nā mea kemika ma kahi ʻili i ʻino.Eia hou, ua hoʻohana ʻia ka X-ray photoelectron spectroscopy (XPS) no ka hoʻoholo ʻana i ke kūpaʻa o ka passivation film oxide ma lalo o ka mana o kahi kaiapuni moana i loaʻa iā Pseudomonas aeruginosa.Ua ana ʻia ka hohonu o nā lua ma lalo o kahi confocal laser scanning microscope (CLSM).
Hōʻike ka Papa 1 i ka haku mele ʻana o 2707 HDSS.Hōʻike ka Papa 2 i ka 2707 HDSS i nā waiwai mechanical maikaʻi loa me ka ikaika o 650 MPa.Ma ka fig.Hōʻike ka 1 i ka microstructure optical o ka hopena wela i mālama ʻia 2707 HDSS.I loko o ka microstructure i loaʻa ma kahi o 50% austenite a me 50% ferrite phases, ʻike ʻia nā kaula elongated o austenite a me ferrite me ka ʻole o nā pae lua.
Ma ka fig.Hōʻike ka 2a i ka hikiwawe kaapuni hāmama (Eocp) me ka manawa hōʻike no 2707 HDSS ma 2216E abiotic medium a me P. aeruginosa broth no 14 mau lā ma 37°C.Hōʻike ia i ka hoʻololi nui a nui loa i ka Eocp i loko o nā hola 24 mua.Ua piʻi nā waiwai Eocp ma nā hihia ʻelua ma -145 mV (hoʻohālikelike ʻia me SCE) ma kahi o 16 mau hola a laila hāʻule nui, hiki i -477 mV (hoʻohālikelike ʻia me SCE) a me -236 mV (hoʻohālikelike ʻia me SCE) no ka laʻana abiotic.a me P Pseudomonas aeruginosa coupons).Ma hope o nā hola 24, ua paʻa ka waiwai Eocp 2707 HDSS no P. aeruginosa ma -228 mV (i hoʻohālikelike ʻia me SCE), ʻoiai ʻo ka waiwai kūpono no nā laʻana non-biological ma kahi o -442 mV (hoʻohālikelike ʻia me SCE).Eocp ma ke alo o P. aeruginosa he haahaa loa.
Haʻawina electrochemical o 2707 HDSS laʻana i loko o ka abiotic a me Pseudomonas aeruginosa broth ma 37 °C:
(a) Eocp ma ke ano he hana o ka manawa hoike, (b) ka polarization curve ma ka la 14, (c) Rp ma ke ano he hana o ka manawa hoike, a (d) icorr ma ke ano he hana o ka manawa hoike.
Hōʻike ka papa 3 i nā ʻāpana electrochemical corrosion o 2707 HDSS laʻana i hōʻike ʻia i ka abiotic a me ka Pseudomonas aeruginosa inoculated media ma kahi o 14 mau lā.Ua hoʻonui ʻia nā tangents o ka anode a me ka cathode curves no ka loaʻa ʻana o nā intersections e hāʻawi ana i ka corrosion current density (icorr), corrosion potential (Ecorr) a me Tafel slope (βα a me βc) e like me nā ala maʻamau30,31.
E like me ka hoike ana ma ka fig.2b, he hoʻololi i luna o ka P. aeruginosa curve i hoʻonui ai i ka Ecorr i hoʻohālikelike ʻia me ka curve abiotic.ʻO ka waiwai icorr, e like me ka nui o ka corrosion, ua hoʻonui ʻia i ka 0.328 µA cm-2 i loko o ka hāpana Pseudomonas aeruginosa, ʻehā mau manawa ʻoi aku ka nui ma mua o ka hāpana non-biological (0.087 µA cm-2).
ʻO LPR kahi hana electrochemical maʻamau no ka nānā ʻana i ka corrosion wikiwiki.Ua hoʻohana ʻia e aʻo i ka MIC32.Ma ka fig.Hōʻike ʻo 2c i ke kūpaʻa polarization (Rp) ma ke ʻano he hana o ka manawa hōʻike.ʻO ke kumu kūʻai Rp kiʻekiʻe, ʻo ia ka liʻiliʻi o ka corrosion.I loko o nā hola 24 mua, ua piʻi ka Rp 2707 HDSS ma ka 1955 kΩ cm2 no nā mea hoʻohālike abiotic a me 1429 kΩ cm2 no nā specimens Pseudomonas aeruginosa.Hōʻike pū ka Paʻi 2c i ka emi wikiwiki ʻana o ke kumukūʻai Rp ma hope o hoʻokahi lā a laila ʻaʻole i loli iki i nā lā he 13 e hiki mai ana.ʻO ka waiwai Rp o kahi laʻana Pseudomonas aeruginosa ma kahi o 40 kΩ cm2, ʻoi aku ka haʻahaʻa ma mua o ka waiwai 450 kΩ cm2 o kahi hāpana olaola ʻole.
Ua like ka waiwai o ka icorr i ka helu corrosion like.Hiki ke helu 'ia kona waiwai mai ka hoohalike Stern-Giri:
Wahi a Zoe et al.33, ua lawe ʻia ka waiwai maʻamau o ka pali Tafel B ma kēia hana he 26 mV/dec.Hōʻike ka Figure 2d i ka icorr o ka hāpana non-biological 2707 i noho paʻa, oiai ka P. aeruginosa hāpana fluctuated nui ma hope o ka mua 24 hola.ʻO nā waiwai icorr o nā laʻana P. aeruginosa he ʻoi aku ka kiʻekiʻe ma mua o nā mana non-biological.Kūlike kēia ʻano me nā hopena o ke kū'ē polarization.
ʻO ka EIS kekahi ʻano hana ʻino ʻole i hoʻohana ʻia e ʻike i nā hopena electrochemical ma nā ʻaoʻao i ʻino.Impedance spectra a me ka helu capacitance waiwai o nā laʻana i hōʻike ʻia i ka abiotic a me ka Pseudomonas aeruginosa solution, passive film/biofilm resistance Rb i hoʻokumu ʻia ma ka ʻaoʻao hiʻohiʻona, ka hoʻoili ʻana i ke kūʻē Rct, ka uila pālua pālua capacitance Cdl (EDL) a me nā ʻāpana ʻāpana QCPE Phase mau. (CPE ).Hoʻopili hou ʻia kēia mau ʻāpana ma ka hoʻopili ʻana i ka ʻikepili me ka hoʻohana ʻana i ke ʻano hoʻohālike like (EEC).
Ma ka fig.Hōʻike ʻo 3 i nā ʻāpana Nyquist maʻamau (a a me b) a me nā ʻāpana Bode (a' a me b') no nā laʻana 2707 HDSS i ka media abiotic a me ka broth P. aeruginosa no nā manawa incubation like ʻole.E emi ana ke anawaena o ke apo Nyquist ma ke alo o Pseudomonas aeruginosa.Hōʻike ka ʻāpana Bode (Fig. 3b ') i ka piʻi ʻana o ka impedance holoʻokoʻa.Hiki ke loaʻa ka ʻike e pili ana i ka manawa hoʻomaha mau mai ka pae maxima.Ma ka fig.Hōʻike ka 4 i nā hale kino e pili ana i kahi monolayer (a) a me kahi bilayer (b) a me nā EEC pili.Hoʻokomo ʻia ʻo CPE i ke ʻano hoʻohālike EEC.Hōʻike ʻia kona ʻae a me ka impedance penei:
ʻElua mau hiʻohiʻona kino a me nā kaapuni like like no ka hoʻopili ʻana i ka spectrum impedance o ka laʻana 2707 HDSS:
ʻo Y0 ka waiwai KPI, j ka helu noʻonoʻo a i ʻole (-1) 1/2, ʻo ω ka alapine angular, n ʻo ia ka helu mana KPI ma lalo o hoʻokahi35.ʻO ka hoʻohuli ʻana i ke kūʻē ʻana o ka hoʻoili kālā (ʻo ia hoʻi, 1/Rct) pili i ka nui o ka corrosion.ʻO ka liʻiliʻi Rct, ʻoi aku ka kiʻekiʻe o ka corrosion rate27.Ma hope o 14 mau lā o ka incubation, hiki i ka Rct o Pseudomonas aeruginosa nā laʻana i 32 kΩ cm2, ʻoi aku ka liʻiliʻi ma mua o ka 489 kΩ cm2 o nā laʻana non-biological (Table 4).
ʻO nā kiʻi CLSM a me nā kiʻi SEM ma ke Kiʻi 5 e hōʻike maopopo ana i ka uhi ʻana o ka biofilm ma ka ʻili o ka laʻana HDSS 2707 ma hope o nā lā 7 he ʻeleʻele.Eia naʻe, ma hope o 14 mau lā, ʻilihune ka uhi ʻana o ka biofilm a ʻike ʻia kekahi mau mea make.Hōʻike ka papa 5 i ka mānoanoa biofilm ma nā laʻana 2707 HDSS ma hope o ka ʻike ʻana iā P. aeruginosa no 7 a me 14 mau lā.Ua hoʻololi ʻia ka mānoanoa biofilm kiʻekiʻe mai 23.4 µm ma hope o 7 mau lā a i 18.9 µm ma hope o 14 mau lā.Ua hōʻoia pū ka mānoanoa biofilm maʻamau i kēia ʻano.Ua emi mai ka 22.2 ± 0.7 μm ma hope o 7 mau lā i 17.8 ± 1.0 μm ma hope o 14 lā.
(a) 3-D CLSM kiʻi ma 7 lā, (b) 3-D CLSM kiʻi ma 14 lā, (c) SEM kiʻi ma 7 lā, a (d) SEM kiʻi ma 14 lā.
Ua hōʻike ʻo EMF i nā mea kemika i loko o nā biofilms a me nā huahana corrosion ma nā laʻana i hōʻike ʻia i P. aeruginosa no 14 mau lā.Ma ka fig.Hōʻike ka Figure 6 ʻoi aku ka kiʻekiʻe o ka maʻiʻo o C, N, O, a me P i nā biofilms a me nā huahana corrosion ma mua o nā metala maʻemaʻe, no ka mea, pili kēia mau mea me nā biofilms a me kā lākou metabolites.Pono nā microbes i ka nui o ka chromium a me ka hao.ʻO nā kiʻekiʻe kiʻekiʻe o Cr a me Fe i loko o ka biofilm a me nā huahana corrosion ma ka ʻili o nā laʻana e hōʻike ana ua nalowale ka matrix metala ma muli o ka pala.
Ma hope o 14 mau lā, ua ʻike ʻia nā lua me ka P. aeruginosa ma waena o 2216E.Ma mua o ka hoʻoulu ʻana, ua maʻalahi ka ʻili o nā laʻana a me ke kīnā ʻole (Fig. 7a).Ma hope o ka hoʻoulu ʻana a me ka wehe ʻana i nā huahana biofilm a me ka corrosion, ua nānā ʻia nā lua hohonu loa ma ka ʻili o nā laʻana me ka hoʻohana ʻana i ka CLSM, e like me ka hōʻike ʻana ma ka Fig. 7b a me c.ʻAʻohe lua i ʻike ʻia ma ka ʻili o nā mea hoʻomalu ola ʻole (0.02 µm ka hohonu lua o ka lua).ʻO ka hohonu o ka lua nui i hana ʻia e P. aeruginosa he 0.52 µm i nā lā 7 a me 0.69 µm i nā lā he 14, e pili ana i ka hohonu o ka lua kiʻekiʻe loa mai nā laʻana 3 (ua koho ʻia nā hohonu lua he 10 no kēlā me kēia hāpana).Loaʻa i ka 0.42 ± 0.12 µm a me 0.52 ± 0.15 µm, i kēlā me kēia (Paukū 5).He liʻiliʻi kēia mau waiwai hohonu hole akā he mea nui.
(a) ma mua o ka ʻike ʻia ʻana, (b) 14 mau lā i loko o kahi kaiapuni abiotic, a (c) 14 mau lā i ka broth Pseudomonas aeruginosa.
Ma ka fig.Hōʻike ka Papa 8 i ke kikoʻī XPS o nā ʻāpana hāpana like ʻole, a ua hōʻuluʻulu ʻia ka haku mele ʻana no kēlā me kēia ʻili ma ka Papa 6. Ma ka Papa 6, ʻo nā pākēneka atomika o Fe a me Cr i mua o P. aeruginosa (nā laʻana A a me B). ʻoi aku ka haʻahaʻa ma mua o nā mea hoʻomalu non-biological.(nā laʻana C a me D).No kahi laʻana P. aeruginosa, ua hoʻokomo ʻia ka ʻōkuhi spectral ma ke kiʻekiʻe o ka Cr 2p nucleus i ʻehā mau ʻāpana kiʻekiʻe me ka ikaika hoʻopaʻa (BE) o 574.4, 576.6, 578.3 a me 586.8 eV, hiki ke hoʻopili ʻia iā Cr, Cr2O3, CrO3 .a me Cr(OH)3, pakahi (Fig. 9a a me b).No nā laʻana olaola ʻole, aia i loko o ka spectrum o ka pae Cr 2p nui ʻelua mau piko nui no Cr (573.80 eV no BE) a me Cr2O3 (575.90 eV no BE) ma Fig.9c a me d.ʻO ka ʻokoʻa ʻoi loa ma waena o nā laʻana abiotic a me nā laʻana P. aeruginosa ʻo ia ka noho ʻana o Cr6+ a me kahi ʻāpana pili kiʻekiʻe o Cr(OH)3 (BE 586.8 eV) ma lalo o ka biofilm.
ʻO ka laulā XPS ākea o ka ʻili o ka laʻana 2707 HDSS i ʻelua mau pāpaʻi he 7 a me 14 mau lā.
(a) 7 lā i ka P. aeruginosa, (b) 14 mau lā i ka P. aeruginosa, (c) 7 lā i loko o kahi abiotic, a (d) 14 mau lā ma kahi abiotic.
Hōʻike ka HDSS i kahi kiʻekiʻe o ka pale ʻana i ka corrosion i ka hapa nui o nā kaiapuni.Ua hōʻikeʻo Kim et al.2 uaʻikeʻiaʻo HDSS UNS S32707 he DSS i hoʻohui nuiʻia me kahi PREN nui aʻe ma mua o 45. ʻO ka waiwai PREN o ka hōʻailona 2707 HDSS i kēia hana he 49. ʻO kēia ma muli o ka nui o ka chromium a me ka kiʻekiʻe o ka waihona. ka molybdenum a me ka nickel, he mea pono i nā wahi ʻawaʻawa.a me nā kaiapuni me ka chloride kiʻekiʻe.Eia kekahi, he mea pono ka haku mele ʻana a me ka microstructure kīnā ʻole no ka paʻa paʻa a me ka pale ʻana i ka corrosion.Eia naʻe, ʻoiai ʻo kona kūpaʻa kemika maikaʻi loa, hōʻike ka ʻikepili hoʻokolohua ma kēia hana ʻaʻole pale loa ʻo 2707 HDSS i nā MIC biofilm P. aeruginosa.
Ua hōʻike nā hopena electrochemical i ka nui o ka corrosion o 2707 HDSS i ka broth P. aeruginosa i hoʻonui nui ʻia ma hope o 14 mau lā i hoʻohālikelike ʻia me ke ʻano o ka biobiological.Ma ke Kiʻi 2a, ua ʻike ʻia ka emi ʻana o ka Eocp ma ka abiotic a me ka broth P. aeruginosa i nā hola 24 mua.Ma hope o kēlā, uhi piha ka biofilm i ka ʻili o ka hāpana, a lilo ʻo Eocp i mea paʻa36.Eia naʻe, ʻoi aku ka kiʻekiʻe o ka pae biological Eocp ma mua o ka pae Eocp non-biological.Aia nā kumu e manaʻoʻiʻo ai ua pili kēia ʻokoʻa me ka hoʻokumu ʻana o nā biofilms P. aeruginosa.Ma ka fig.2d i ke alo o P. aeruginosa, ua hiki i ka waiwai icorr 2707 HDSS i 0.627 μA cm-2, he kauoha ia o ka nui ma mua o ka mana abiotic (0.063 μA cm-2), i kūlike me ka Rct waiwai i anaia. na EIS.I loko o nā lā mua, ua hoʻonui ʻia nā waiwai impedance i ka broth P. aeruginosa ma muli o ka hoʻopili ʻana o nā cell P. aeruginosa a me ka hoʻokumu ʻana o nā biofilms.Eia naʻe, ke uhi piha ka biofilm i ka ʻili hoʻohālike, e emi ana ka impedance.Hoʻouka mua ʻia ka papa pale ma muli o ka hoʻokumu ʻana o nā biofilms a me nā metabolites biofilm.No laila, ua emi ke kūpale ʻana i ka ʻino i ka manawa a me ka hoʻopili ʻana o P. aeruginosa i hoʻopōʻino ʻia.ʻOkoʻa nā ʻano o nā kaiapuni abiotic.ʻOi aku ka kiʻekiʻe o ke kūpaʻa ʻino o ka mana non-biological ma mua o ka waiwai kūpono o nā laʻana i hōʻike ʻia i ka broth P. aeruginosa.Eia kekahi, no ke komo ʻana abiotic, hiki i ka waiwai Rct 2707 HDSS i ka 489 kΩ cm2 ma ka lā 14, ʻo ia ka 15 mau manawa kiʻekiʻe ma mua o ka waiwai Rct (32 kΩ cm2) i mua o P. aeruginosa.No laila, ʻo 2707 HDSS he kūpaʻa maikaʻi loa i ka corrosion i loko o kahi wahi sterile, akā ʻaʻole kūʻē i nā MIC mai nā biofilms P. aeruginosa.
Hiki ke ʻike ʻia kēia mau hopena mai nā pihi polarization ma Fig.2b.Hoʻopili ʻia ka lālā anodic me ka hoʻokumu ʻana o ka biofilm Pseudomonas aeruginosa a me nā hopena oxidation metala.I kēia hihia, ʻo ka hopena cathodic ka hoʻemi ʻana o ka oxygen.ʻO ka loaʻa ʻana o P. aeruginosa i hoʻonui nui i ka nui o ka corrosion o kēia manawa, e pili ana i kahi kauoha o ka nui ma mua o ka mana abiotic.Hōʻike kēia i ka biofilm P. aeruginosa e hoʻonui i ka corrosion localized o 2707 HDSS.Ua ʻike ʻo Yuan et al.29 ua hoʻonui ʻia ka nui o ka corrosion o ka hui Cu-Ni 70/30 ma lalo o ka hana a P. aeruginosa biofilm.ʻO kēia paha ma muli o ka biocatalysis o ka hoʻemi ʻana o ka oxygen e nā biofilms Pseudomonas aeruginosa.Hiki i kēia ʻike ke wehewehe i ka MIC 2707 HDSS i kēia hana.He emi paha ka oxygen ma lalo o nā biofilm aerobic.No laila, ʻo ka hōʻole ʻana i ka hoʻihoʻi hou ʻana i ka ʻili metala me ka oxygen he mea ia e kōkua ai i ka MIC i kēia hana.
ʻO Dickinson et al.Manaʻo ʻo 38 e hiki ke hoʻopili pololei ʻia ka nui o nā hopena kemika a me ka electrochemical e ka hana metabolic o ka bacteria sessile ma ka ʻili hoʻohālike a me ke ʻano o nā huahana corrosion.E like me ka mea i hōʻike ʻia ma ka Figure 5 a me ka Papa 5, ua emi ka helu o nā cell a me ka mānoanoa biofilm ma hope o 14 mau lā.Hiki ke wehewehe ʻia kēia ma ka ʻoiaʻiʻo ma hope o 14 mau lā, make ka hapa nui o nā cell sessile ma ka ʻili o 2707 HDSS ma muli o ka pau ʻana o ka meaʻai ma ka 2216E medium a i ʻole ka hoʻokuʻu ʻana i nā ion metala ʻona mai ka 2707 HDSS matrix.He palena kēia o nā hoʻokolohua pūʻulu.
Ma kēia hana, ua hāʻawi kahi biofilm P. aeruginosa i ka hoʻopau kūloko o Cr a me Fe ma lalo o ka biofilm ma ka ʻili o 2707 HDSS (Fig. 6).Hōʻike ka papa 6 i ka emi ʻana o Fe a me Cr i ka laʻana D i hoʻohālikelike ʻia me ka laʻana C, e hōʻike ana ua hoʻomau ka Fe a me Cr i hoʻoheheʻe ʻia e ka biofilm P. aeruginosa no nā lā 7 mua.Hoʻohana ʻia ke kaiapuni 2216E e hoʻohālikelike i ke kaiapuni kai.Loaʻa iā ia ka 17700 ppm Cl-, kahi i hoʻohālikelike ʻia me kona ʻike i loko o ka wai kai maoli.ʻO ka loaʻa ʻana o 17700 ppm Cl- ke kumu nui o ka emi ʻana o ka Cr ma 7- a me 14 mau lā abiotic laʻana i kālai ʻia e XPS.Ke hoʻohālikelike ʻia me nā laʻana P. aeruginosa, ʻoi aku ka liʻiliʻi o ka hoʻoheheʻe ʻana o Cr i nā laʻana abiotic ma muli o ke kūpaʻa ikaika o 2707 HDSS i ka chlorine ma lalo o nā kūlana abiotic.Ma ka fig.Hōʻike ka 9 i ka hele ʻana o Cr6+ i ke kiʻiʻoniʻoni passivating.Hiki ke komo i ka wehe ʻana i ka chromium mai nā ʻili kila e nā biofilms P. aeruginosa, e like me ka manaʻo o Chen a me Clayton.
Ma muli o ka ulu ʻana o ka bacteria, ʻo 7.4 a me 8.2 ka pH o ka waena ma mua a ma hope o ke kanu ʻana.No laila, ma lalo o ka P. aeruginosa biofilm, ʻaʻole hiki ke hāʻawi i ka corrosion acid organik i kēia hana ma muli o ke kiʻekiʻe o ka pH i loko o ka mea nui.ʻAʻole i loli nui ka pH o ka mea hoʻokele non-biological control (mai ka 7.4 mua a i ka 7.5 hope) i ka wā hoʻāʻo 14 lā.ʻO ka piʻi ʻana o ka pH i loko o ka inoculation medium ma hope o ka incubation ua pili pū me ka hana metabolic o P. aeruginosa a ua ʻike ʻia he hopena like i ka pH me ka loaʻa ʻole o nā ʻāpana hoʻāʻo.
E like me ka mea i hōʻike ʻia ma ke Kiʻi 7, ʻo ka hohonu o ka lua nui i hoʻokumu ʻia e ka biofilm P. aeruginosa he 0.69 µm, ʻoi aku ka ʻoi aku o ka hohonu o ka lua abiotic (0.02 µm).Kūlike kēia me ka ʻikepili electrochemical i hōʻike ʻia ma luna.ʻOi aku ka hohonu o ka lua o 0.69 µm ma mua o ʻumi manawa liʻiliʻi ma mua o ka waiwai 9.5 µm i hōʻike ʻia no 2205 DSS ma lalo o nā kūlana like.Hōʻike kēia mau ʻikepili e hōʻike ana ʻo 2707 HDSS i ke kūʻē maikaʻi ʻana i nā MIC ma mua o 2205 DSS.ʻAʻole kēia he mea kāhāhā no ka loaʻa ʻana o nā pae Cr kiʻekiʻe o 2707 HDSS e hāʻawi ana i ka passivation lōʻihi, ʻoi aku ka paʻakikī o ka hoʻopau ʻana iā P. aeruginosa, a ma muli o ke ʻano o ka pae kaulike me ka ʻole o ka ua lua pōʻino ke kumu o ka pitting.
I ka hopena, ua loaʻa nā lua MIC ma ka ʻili o 2707 HDSS i ka broth P. aeruginosa i hoʻohālikelike ʻia me nā lua liʻiliʻi i ka ʻāina abiotic.Hōʻike kēia hana i ka 2707 HDSS ʻoi aku ka maikaʻi o ke kūʻē ʻana i ka MIC ma mua o 2205 DSS, akā ʻaʻole paʻa loa ia i ka MIC ma muli o ka biofilm P. aeruginosa.Ke kōkua nei kēia mau hopena i ke koho ʻana i nā kila kuhili ʻole kūpono a me ka manaʻolana ola no ke kaiapuni kai.
Kupon no 2707 HDSS i hāʻawi ʻia e Northeastern University (NEU) School of Metallurgy ma Shenyang, Kina.Hōʻike ʻia ka haku mele o 2707 HDSS ma ka Papa 1, i nānā ʻia e ka NEU Materials Analysis and Testing Department.Ua mālama ʻia nā laʻana a pau no ka hoʻonā paʻa ma 1180°C no 1 hola.Ma mua o ka hoʻāʻo ʻana i ka corrosion, ua hoʻomaʻamaʻa ʻia kahi ʻāpana kālā 2707 HDSS me kahi ākea ākea o 1 cm2 i 2000 grit me ka silicon carbide sandpaper a laila poni ʻia me ka 0.05 µm Al2O3 pauka slurry.Mālama ʻia nā ʻaoʻao a me lalo me ka pena inert.Ma hope o ka maloʻo ʻana, holoi ʻia nā laʻana me ka wai deionized sterile a sterilized me 75% (v / v) ethanol no 0.5 h.Hoʻomaloʻo ʻia lākou ma lalo o ke kukui ultraviolet (UV) no 0.5 mau hola ma mua o ka hoʻohana ʻana.
Ua kūʻai ʻia ʻo Marine Pseudomonas aeruginosa strain MCCC 1A00099 mai ka Xiamen Marine Culture Collection Center (MCCC), Kina.Ua ulu ka Pseudomonas aeruginosa ma lalo o nā kūlana aerobic ma 37 ° C. ma 250 ml flasks a me 500 ml aniani electrochemical cell e hoʻohana ana i Marine 2216E wai medium (Qingdao Hope Biotechnology Co., Ltd., Qingdao, Kina).Hilikia odium (g / L): 19.45 Nacl, 5.98 MRLL3, 08 Ka2co3n, 08836 N2SO3, 08- 1 hū hū a me 0.1 hao citrate.Autoclave ma 121 ° C no 20 mau minuke ma mua o ka inoculation.E helu i nā pūnaewele sessile a me planktonic me ka hemocytometer ma lalo o kahi microscope māmā ma ka hoʻonui 400x.ʻO ka neʻe mua ʻana o ka planktonic Pseudomonas aeruginosa ma hope koke o ka inoculation ma kahi o 106 mau cell / ml.
Ua lawe ʻia nā hoʻāʻo electrochemical i loko o kahi keʻena aniani ʻekolu-electrode maʻamau me ka nui o 500 ml.Ua hoʻopili ʻia ka platinum sheet a me ka saturated calomel electrode (SAE) i ka reactor ma o nā capillaries Luggin i hoʻopiha ʻia me nā alahaka paʻakai, i lawelawe ʻia ma ke ʻano he counter a me nā electrodes kuhikuhi.No ka hana ʻana i nā electrodes hana, ua hoʻopili ʻia ke kaula keleawe rubberized i kēlā me kēia laʻana a uhi ʻia me ka resin epoxy, e waiho ana ma kahi o 1 cm2 o ka wahi i pale ʻole ʻia no ka electrode hana ma kekahi ʻaoʻao.I ka wā o nā ana electrochemical, ua waiho ʻia nā laʻana i loko o ka medium 2216E a mālama ʻia i kahi mahana incubation mau (37 ° C) i loko o kahi ʻauʻau wai.ʻO OCP, LPR, EIS a me nā ʻikepili polarization hiki ke ana ʻia me ka hoʻohana ʻana i kahi Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA).Ua hoʻopaʻa ʻia nā hoʻāʻo LPR ma kahi helu scan o 0.125 mV s-1 ma ka laulā o -5 a hiki i 5 mV me Eocp a me kahi helu sampling o 1 Hz.Ua hana ʻia ʻo EIS me kahi hawewe sine ma luna o ke alapinepine o 0.01 a 10,000 Hz me ka hoʻohana ʻana i ka volta i hoʻohana ʻia o 5 mV ma ke kūlana paʻa Eocp.Ma mua o ke kāhili ʻana, aia nā electrodes i ke ʻano hana ʻole a hiki i ka loaʻa ʻana o kahi waiwai paʻa o ka hiki ke hoʻoheheʻe manuahi.A laila ua ana ʻia nā ʻāpana polarization mai -0.2 a i 1.5 V ma ke ʻano he hana o Eocp ma ka helu scan o 0.166 mV/s.Ua hana hou ʻia kēlā me kēia hoʻāʻo ʻana i 3 mau manawa me ka P. aeruginosa a me ka ʻole.
ʻO nā laʻana no ka nānā ʻana i ka metallographic i hoʻomaloʻo ʻia me ka pepa 2000 grit SiC pulu a laila hoʻomaʻamaʻa hou ʻia me ka 0.05 µm Al2O3 pauda hoʻokuʻu ʻia no ka nānā ʻana.Hoʻohana ʻia ka ʻike metallographic me ka microscope optical.Ua kālai ʻia nā laʻana me kahi solution 10 wt% o ka potassium hydroxide 43.
Ma hope o ka incubation, holoi ʻia nā laʻana i nā manawa 3 me ka phosphate buffered saline (PBS) (pH 7.4 ± 0.2) a laila hoʻopaʻa ʻia me 2.5% (v/v) glutaraldehyde no 10 mau hola e hoʻoponopono ai i nā biofilms.A laila ua hoʻomaloʻo ʻia me ka ethanol batched (50%, 60%, 70%, 80%, 90%, 95% a me 100% ma ka leo) ma mua o ka maloʻo ʻana o ka ea.ʻO ka hope, waiho ʻia kahi kiʻi gula ma ka ʻili o ka hāpana e hāʻawi i ka conductivity no ka nānā ʻana iā SEM.Ua kālele ʻia nā kiʻi SEM ma nā kiko me nā pūnaewele P. aeruginosa loa ma ka ʻili o kēlā me kēia hāpana.E hana i ka nānā ʻana i ka EDS no ka ʻimi ʻana i nā mea kemika.Ua hoʻohana ʻia kahi Zeiss confocal laser scanning microscope (CLSM) (LSM 710, Zeiss, Kelemānia) e ana i ka hohonu o ka lua.No ka nānā ʻana i nā lua ʻino ma lalo o ka biofilm, ua hoʻomaʻemaʻe mua ʻia ka laʻana hoʻāʻo e like me ka Chinese National Standard (CNS) GB/T4334.4-2000 e wehe i nā huahana corrosion a me biofilm mai ka ʻili o ka hāpana hoʻāʻo.
X-ray photoelectron spectroscopy (XPS, ESCALAB250 surface analysis system, Thermo VG, USA) ua hana ʻia me ka hoʻohana ʻana i kahi kumu X-ray monochromatic (laina Aluminum Kα me ka ikehu o 1500 eV a me ka mana o 150 W) i kahi ākea ākea. nā ikehu paʻa 0 ma lalo o nā kūlana maʻamau o –1350 eV.Ua hoʻopaʻa ʻia ka spectra hoʻonā kiʻekiʻe me ka hoʻohana ʻana i ka ikehu hoʻoili o 50 eV a me kahi ʻanuʻu o 0.2 eV.
Ua wehe ʻia nā laʻana incubated a holoi ʻia me ka PBS (pH 7.4 ± 0.2) no 15 s45.No ka nānā ʻana i ka hiki ʻana o ka maʻi bacteria o nā biofilms ma nā laʻana, ua hoʻopaʻa ʻia nā biofilms me ka hoʻohana ʻana i ka LIVE / DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA).Aia i loko o ka pahu nā mea hoʻonanea ʻelua: SYTO-9 ʻulaʻula ʻulaʻula a me propidium iodide (PI).Ma CLSM, hōʻike nā kiko ʻōmaʻomaʻo a me ka ʻulaʻula i nā mea ola a me nā mea make.No ka hoʻopaʻa ʻana, ua hoʻokomo ʻia ka 1 ml o ka hui ʻana i loko o 3 µl o SYTO-9 a me 3 µl o ka solution PI no 20 mau minuke ma ka lumi wela (23°C) i ka pōʻeleʻele.Ma hope mai, ua nānā ʻia nā laʻana stained ma ʻelua nalu nalu (488 nm no nā cell ola a me 559 nm no nā cell make) me ka hoʻohana ʻana i kahi mea hana Nikon CLSM (C2 Plus, Nikon, Iapana).Ua ana ʻia ka mānoanoa biofilm ma ke ʻano scanning 3D.
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