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Uphuhliso olukhawulezileyo lwe-nanotechnology kunye nokuhlanganiswa kwayo kwizicelo zemihla ngemihla kunokubeka emngciphekweni okusingqongileyo. Nangona iindlela eziluhlaza zokonakalisa izinto ezingcolisayo eziphilayo zisekiwe kakuhle, ukubuyiselwa kwezinto ezingcolisayo ezingabonakaliyo kwi-crystalline kuyinto exhalabisayo kakhulu ngenxa yobuthathaka bazo obuphantsi kwi-biotransformation kunye nokungaqondi ukusebenzisana kwezinto ezisemgangathweni kunye nezo zebhayoloji. Apha, sisebenzisa imodeli ye-2D MXenes engabonakaliyo esekwe kwi-Nb edityaniswe nendlela elula yohlalutyo lweeparamitha zemilo ukulandelela indlela yokulungiswa kwezinto eziphilayo ze-2D ceramic nanomaterials yi-green microalgae Raphidocelis subcapitata. Sifumanise ukuba i-microalgae yonakalisa i-MXenes esekwe kwi-Nb ngenxa yokusebenzisana okunxulumene ne-physico-chemical. Ekuqaleni, ii-nanoflakes ze-MXene ezineleya enye kunye neleya ezininzi zazinamathele kumphezulu we-microalgae, nto leyo eyanciphisa ukukhula kwe-algae. Nangona kunjalo, xa isebenzisana ixesha elide nomphezulu, i-microalgae yaxovula ii-nanoflakes ze-MXene yaza yazibolisa ngakumbi kwi-NbO kunye ne-Nb2O5. Ngenxa yokuba ezi oxides azinabungozi kwiiseli ze-microalgae, zitya ii-nanoparticles ze-Nb oxide ngendlela yokufunxa ebuyisela i-microalgae emva kweeyure ezingama-72 zokunyanga ngamanzi. Iziphumo zezondlo ezinxulumene nokufunxa zikwabonakala ekwandeni komthamo weseli, imo yazo egudileyo kunye notshintsho kwisantya sokukhula. Ngokusekelwe kwezi ziphumo, sigqiba kwelokuba ubukho bexesha elifutshane nelide be-MXenes ezisekelwe kwi-Nb kwiindawo eziphilayo zamanzi acocekileyo bunokubangela iimpembelelo ezincinci kuphela kwindalo. Kuyaphawuleka ukuba, sisebenzisa ii-nanomaterials ezimbini-dimensional njengeenkqubo zemodeli, sibonisa ukuba kunokwenzeka ukulandelela utshintsho lwesimo nakwizinto ezicoliweyo. Ngokubanzi, olu phononongo luphendula umbuzo obalulekileyo osisiseko malunga neenkqubo ezinxulumene nokusebenzisana komphezulu eziqhuba indlela yokulungisa i-bioremediation ye-2D nanomaterials kwaye lubonelela ngesiseko sezifundo zexesha elifutshane nelide zempembelelo kwindalo ye-nanomaterials ezingaphiliyo.
Izinto ezisetyenziswa kwi-nanomaterials ziye zabangela umdla omkhulu ukusukela oko zafunyanwa, kwaye ii-nanotechnologies ezahlukeneyo kutshanje zingene kwisigaba sokuhlaziya1. Ngelishwa, ukuhlanganiswa kwezinto ezisetyenziswa kwi-nanomaterials kwizicelo zemihla ngemihla kunokukhokelela ekukhutshweni ngengozi ngenxa yokulahlwa okungafanelekanga, ukuphathwa ngokungakhathali, okanye ukhuseleko olunganelanga. Ke ngoko, kusengqiqweni ukucinga ukuba izinto ezisetyenziswa kwi-nanomaterials, kuquka izinto ezisetyenziswa kwi-nanomaterials ezimbini (2D), zinokukhululwa kwindawo yendalo, indlela yokuziphatha kunye nomsebenzi webhayoloji ezingekaqondwa ngokupheleleyo. Ke ngoko, akumangalisi ukuba iingxaki ze-ecotoxicity zigxile kubuchule bezinto ezisetyenziswa kwi-nanomaterials ze-2D bokungena kwiinkqubo zasemanzini2,3,4,5,6. Kule mimandla yendalo, ezinye izinto ezisetyenziswa kwi-nanomaterials ze-2D zinokusebenzisana nezinto eziphilayo ezahlukeneyo kumanqanaba ahlukeneyo e-trophic, kuquka ne-microalgae.
Ii-Microalgae zizinto eziphilayo zakudala ezifumaneka ngokwendalo kwiindawo zamanzi acocekileyo kunye neendawo zaselwandle ezivelisa iintlobo ngeentlobo zeemveliso zeekhemikhali ngokusebenzisa i-photosynthesis7. Ngenxa yoko, zibalulekile kwiindawo zasemanzini8,9,10,11,12 kodwa zikwabonisa ubuthi, azibizi kakhulu kwaye zisetyenziswa kakhulu kwi-ecotoxicity13,14. Ekubeni iiseli ze-microalgae ziphindaphindeka ngokukhawuleza nangokukhawuleza xa kukho iikhompawundi ezahlukeneyo, zithembisa ukuphuhliswa kweendlela ezinobuhlobo nokusingqongileyo zokunyanga amanzi angcoliswe zizinto eziphilayo15,16.
Iiseli ze-algae zinokususa ii-ion ezingaphiliyo emanzini ngokusebenzisa i-biosorption kunye nokuqokelelana17,18. Ezinye iintlobo ze-algal ezifana neChlorella, i-Anabaena invar, i-Westiellopsis prolica, i-Stigeoclonium tenue kunye ne-Synechococcus sp. Kufunyenwe ukuba ithwala kwaye yondla ii-ion zesinyithi ezinobuthi ezifana ne-Fe2+, i-Cu2+, i-Zn2+ kunye ne-Mn2+19. Ezinye izifundo zibonise ukuba ii-ion ze-Cu2+, i-Cd2+, i-Ni2+, i-Zn2+ okanye i-Pb2+ ziyawuthintela ukukhula kwe-Scenedesmus ngokutshintsha imo yeseli kunye nokutshabalalisa ii-chloroplast zazo20,21.
Iindlela eziluhlaza zokubola kwezinto ezingcolisayo eziphilayo kunye nokususwa kwee-ion zesinyithi esinzima zitsale ingqalelo yoososayensi kunye neenjineli kwihlabathi liphela. Oku kungenxa yokuba ezi zinto zingcolisayo zicutshungulwa lula kwisigaba solwelo. Nangona kunjalo, izinto ezingcolisayo zekristale ezingaphiliyo zibonakaliswa kukunyibilika kwamanzi okuncinci kunye nokungakhuseleki okuncinci kwiinguqu ezahlukeneyo zebhayoloji, nto leyo ebangela ubunzima obukhulu ekulungisweni, kwaye akukho nkqubela ininzi eyenziweyo kule ndawo22,23,24,25,26. Ngoko ke, ukukhangela izisombululo ezinobuhlobo nokusingqongileyo zokulungiswa kwezinto ezingcolisayo kuhlala kuyindawo enzima nengahlolwayo. Ngenxa yokuphakama kokungaqiniseki malunga neziphumo ze-biotransformation zezinto ezingcolisayo ze-2D, akukho ndlela ilula yokufumana iindlela ezinokwenzeka zokuwohloka kwazo ngexesha lokunciphisa.
Kolu phononongo, sisebenzise i-green algae njenge-arhente yokulungisa izinto ezingaphiliyo emanzini, kunye nokubeka esweni inkqubo yokuwohloka kwe-MXene njengommeli wezinto ezingaphiliyo ze-ceramic. Igama elithi "MXene" libonisa i-stoichiometry yezinto ze-Mn+1XnTx, apho i-M yintsimbi yokutshintsha kwasekuqaleni, i-X yi-carbon kunye/okanye i-nitrogen, i-Tx sisiphelisi somphezulu (umz., -OH, -F, -Cl), kunye no-n = 1, 2, 3 okanye 427.28. Ukususela ekufumanekeni kwe-MXenes nguNaguib et al. IiSensorics, unyango lomhlaza kunye nokuhluzwa kwe-membrane 27,29,30. Ukongeza, ii-MXenes zinokuthathwa njengeenkqubo zemodeli ze-2D ngenxa yokuzinza kwazo okuhle kwe-colloidal kunye nokusebenzisana okunokwenzeka kwezinto eziphilayo31,32,33,34,35,36.
Ngoko ke, indlela ephuhliswe kweli nqaku kunye neengcinga zethu zophando ziboniswe kuMfanekiso 1. Ngokwale ngcinga, ii-microalgae ziyonakalisa ii-MXenes ezisekelwe kwi-Nb zibe ziikhompawundi ezingezizo iityhefu ngenxa yokusebenzisana okunxulumene ne-physico-chemical okunxulumene nomphezulu, okuvumela ukubuyiselwa ngakumbi kwe-algae. Ukuvavanya le ngcinga, kukhethwe amalungu amabini osapho lwee-carbides zesinyithi ezisekelwe kwi-niobium kunye/okanye ii-nitrides (MXenes), ezizezi i-Nb2CTx kunye ne-Nb4C3TX.
Indlela yophando kunye neengcinga ezisekelwe kubungqina bokubuyiselwa kwe-MXene yi-green microalgae Raphidocelis subcapitata. Nceda uqaphele ukuba oku kukubonakaliswa nje kweengcamango ezisekelwe kubungqina. Indawo engqongileyo yechibi yahlukile kwi-nutrient medium esetyenziswayo kunye neemeko (umz., umjikelo wemini kunye nemida kwizondlo ezibalulekileyo ezikhoyo). Yenziwe ngeBioRender.com.
Ngoko ke, ngokusebenzisa iMXene njengenkqubo yomzekelo, sivule ucango lokufunda ngeziphumo ezahlukeneyo zebhayoloji ezingenakubonwa ngezinye izinto ze-nanomaterials eziqhelekileyo. Ngokukodwa, sibonisa ukuba kunokwenzeka ukulungiswa kwezinto ze-nanomaterials ezimbini-dimensional, njenge-MXenes ezisekwe kwi-niobium, yi-microalgae Raphidocelis subcapitata. Ii-Microalgae ziyakwazi ukonakalisa ii-Nb-MXenes zibe zii-oxides ezingezizo ezinobuthi i-NbO kunye ne-Nb2O5, ezibonelela ngezondlo ngokusebenzisa indlela yokufunxwa kwe-niobium. Ngokubanzi, olu phononongo luphendula umbuzo obalulekileyo obalulekileyo malunga neenkqubo ezinxulumene nokusebenzisana kwe-physicochemical kumphezulu ezilawula iindlela zokulungiswa kwezinto ze-nanomaterials ezimbini-dimensional. Ukongeza, siphuhlisa indlela elula esekelwe kwimilo-parameter yokulandelela utshintsho oluncinci kwimo yezinto ze-nanomaterials ze-2D. Oku kuphefumlela uphando oluthe kratya lwexesha elifutshane nexesha elide kwiimpembelelo ezahlukeneyo zokusingqongileyo zezinto ze-nanomaterials ezingaphiliyo. Ke ngoko, uphando lwethu lonyusa ukuqonda kokunxibelelana phakathi komphezulu wezinto kunye nezinto zebhayoloji. Sikwabonelela ngesiseko sophando olwandisiweyo lwexesha elifutshane nexesha elide malunga nefuthe lazo kwindalo ephilayo yamanzi acocekileyo, nto leyo ngoku enokuqinisekiswa ngokulula.
Ii-MXenes zimele udidi olunomdla lwezinto ezinezinto ezibonakalayo nezinomtsalane nezibonakalayo, ngoko ke zininzi izinto ezinokubakho. Ezi mpawu zixhomekeke kakhulu kwi-stoichiometry yazo kunye ne-surface chemistry. Ke ngoko, kuphononongo lwethu, siphande iintlobo ezimbini ze-Nb-based hierarchical single-layer (SL) MXenes, i-Nb2CTx kunye ne-Nb4C3TX, kuba iziphumo ezahlukeneyo zebhayoloji zezi nanomaterials zinokubonwa. Ii-MXenes ziveliswa kwizinto zazo zokuqala ngokukrola okuphezulu kwe-MAX-phase A-layers ezincinci ze-atomically. Isigaba se-MAX si-ceramic ye-ternary eyenziwe ngeebhloko "ezibophelelweyo" zee-transition metal carbides kunye neebhloko ezincinci zezinto "A" ezifana ne-Al, i-Si, kunye ne-Sn kunye ne-MnAXn-1 stoichiometry. Imo yesigaba sokuqala se-MAX yabonwa ngokuskena i-electron microscopy (SEM) kwaye yayihambelana nezifundo zangaphambili (Jonga Ulwazi olongezelelweyo, SI, Umfanekiso S1). I-Multilayer (ML) Nb-MXene ifunyenwe emva kokususa umaleko we-Al nge-48% HF (hydrofluoric acid). Imo ye-ML-Nb2CTx kunye ne-ML-Nb4C3TX ihlolwe ngokuskena i-electron microscopy (SEM) (Imifanekiso S1c kunye ne-S1d ngokulandelelana) kwaye kwabonwa imo ye-MXene eqhelekileyo enamaleko, efana nee-nanoflakes ezimbini ezidlula kwii-slits ezinjenge-pore ezinde. Zombini ii-Nb-MXenes zifana kakhulu ne-MXene phases ezazisenziwa ngaphambili yi-acid etching27,38. Emva kokuqinisekisa ulwakhiwo lwe-MXene, sayibeka ngokudibanisa i-tetrabutylammonium hydroxide (TBAOH) kulandele ukuhlamba kunye ne-sonication, emva koko safumana ii-nanoflakes ze-2D Nb-MXene ezinamaleko omnye okanye ophantsi (SL).
Sisebenzise i-high resolution transmission electron microscopy (HRTEM) kunye ne-X-ray diffraction (XRD) ukuvavanya ukusebenza kakuhle kokugrumba kunye nokuqhekeka ngakumbi. Iziphumo ze-HRTEM ezicutshungulwe kusetyenziswa i-Inverse Fast Fourier Transform (IFFT) kunye ne-Fast Fourier Transform (FFT) ziboniswe kwiFig. 2. Ii-nanoflakes ze-Nb-MXene zazijongiswe emphethweni ukuze zijonge ulwakhiwo lwe-atomic layer kwaye zilinganise imigama ephakathi. Imifanekiso ye-HRTEM yee-nanoflakes ze-MXene Nb2CTx kunye ne-Nb4C3TX zityhile uhlobo lwazo olubhityileyo lwe-atomic (jonga kwiFig. 2a1, a2), njengoko kubikwe ngaphambili nguNaguib et al.27 kunye noJastrzębska et al.38. Kwii-monolayers ezimbini ezikufutshane ze-Nb2CTx kunye ne-Nb4C3Tx, simisele imigama ephakathi kwe-0.74 kunye ne-1.54 nm, ngokulandelelana (IiFig. 2b1,b2), evumelana neziphumo zethu zangaphambili38. Oku kuqinisekiswe ngakumbi yi-inverse fast Fourier transform (Umzobo 2c1, c2) kunye ne-fast Fourier transform (Umzobo 2d1, d2) ebonisa umgama phakathi kwe-Nb2CTx kunye ne-Nb4C3Tx monolayers. Umfanekiso ubonisa utshintsho lweebhendi zokukhanya nezimnyama ezihambelana nee-athomu ze-niobium kunye ne-carbon, nto leyo eqinisekisa ubume bee-MXenes ezifundwayo. Kubalulekile ukuqaphela ukuba i-energy dispersive X-ray spectroscopy (EDX) spectra efunyenwe kwi-Nb2CTx kunye ne-Nb4C3Tx (Imifanekiso S2a kunye ne-S2b) ayibonisanga ntsalela yesigaba sokuqala se-MAX, kuba akukho ncochoyi ye-Al efunyenweyo.
Ukuchazwa kwee-nanoflakes ze-SL Nb2CTx kunye ne-Nb4C3Tx MXene, kuquka (a) i-high resolution electron microscopy (HRTEM) side-view 2D nanoflake imaging kunye ne-compatible, (b) i-intensity mode, (c) inverse fast Fourier transform (IFFT), (d) fast Fourier transform (FFT), (e) iipateni ze-X-ray ze-Nb-MXenes. Kwi-SL 2D Nb2CTx, amanani achazwa ngolu hlobo (a1, b1, c1, d1, e1). Kwi-SL 2D Nb4C3Tx, amanani achazwa ngolu hlobo (a2, b2, c2, d2, e1).
Ukulinganiswa kwe-X-ray diffraction ye-SL Nb2CTx kunye ne-Nb4C3Tx MXenes kuboniswe kwiMifanekiso 2e1 kunye ne-e2, ngokulandelelana. Iincochoyi (002) kwi-4.31 kunye ne-4.32 zihambelana ne-MXenes Nb2CTx kunye ne-Nb4C3TX38,39,40,41 ezichazwe ngaphambili ngokulandelelana. Iziphumo ze-XRD zibonisa nokuba kukho ezinye izakhiwo ze-ML ezisele kunye ne-MAX phases, kodwa uninzi lweepateni ze-XRD ezinxulumene ne-SL Nb4C3Tx (Umzobo 2e2). Ubukho beesuntswana ezincinci ze-MAX phase bunokuchaza i-MAX peak eqinileyo xa ithelekiswa nee-Nb4C3Tx layers ezifakwe ngokungacwangciswanga.
Uphando olongezelelweyo lugxile kwi-microalgae eluhlaza ekwi-R. subcapitata. Sikhethe i-microalgae kuba ngabavelisi ababalulekileyo ababandakanyeka kwi-food webs ezinkulu42. Kwakhona yenye yezona zibonakaliso zibalaseleyo zetyhefu ngenxa yokukwazi ukususa izinto ezinobuthi ezithwalwa kumanqanaba aphezulu e-food chain43. Ukongeza, uphando kwi-R. subcapitata lunokukhanyisa ubuthi obungalindelekanga be-SL Nb-MXenes kwiintsholongwane zamanzi acocekileyo eziqhelekileyo. Ukuze kuboniswe oku, abaphandi bacinge ukuba i-microbe nganye inobuntununtunu obahlukileyo kwiikhompawundi ezinobuthi ezikhoyo kwindalo esingqongileyo. Kwiintlobo ezininzi zezinto eziphilayo, ubuninzi bezinto eziphantsi abuchaphazeli ukukhula kwazo, ngelixa ubuninzi obungaphezulu komda othile bunokuzithintela okanye bubangele nokufa. Ke ngoko, kwizifundo zethu zokunxibelelana komphezulu phakathi kwe-microalgae kunye ne-MXenes kunye nokubuyiselwa okunxulumene noko, sigqibe ekubeni sivavanye ubuninzi obungenabungozi nobunobuthi be-Nb-MXenes. Ukuze senze oku, sivavanye uxinaniso lwe-0 (njengereferensi), i-0.01, i-0.1 kunye ne-10 mg l-1 MXene kunye ne-microalgae eyosulelekileyo enoxinaniso oluphezulu kakhulu lwe-MXene (100 mg l-1 MXene), enokuba yingozi kakhulu kwaye ibulale. . kuyo nayiphi na indawo yendalo.
Iziphumo ze-SL Nb-MXenes kwi-microalgae ziboniswe kuMfanekiso 3, ochazwe njengepesenti yokukhuthazwa kokukhula (+) okanye ukuthintela (-) okulinganiswe kwiisampuli ze-0 mg l-1. Ukuthelekisa, isigaba se-Nb-MAX kunye ne-ML Nb-MXenes nazo zivavanyiwe kwaye iziphumo ziboniswe kwi-SI (jonga uMfanekiso S3). Iziphumo ezifunyenweyo ziqinisekisile ukuba i-SL Nb-MXenes phantse ayinayo kwaphela ityhefu kuluhlu lwamanqanaba aphantsi ukusuka kwi-0.01 ukuya kwi-10 mg/l, njengoko kubonisiwe kuMfanekiso 3a,b. Kwimeko ye-Nb2CTx, asibonanga ngaphezulu kwe-5% ye-ecotoxicity kuluhlu oluchaziweyo.
Ukukhuthaza (+) okanye ukuthintela (-) ukukhula kwe-microalgae xa kukho i-SL (a) Nb2CTx kunye (b) Nb4C3TX MXene. Iiyure ezingama-24, 48 kunye nama-72 zokusebenzisana kwe-MXene-microalgae zihlalutyiwe. Idatha ebalulekileyo (uvavanyo lwe-t, p < 0.05) iphawulwe nge-asterisk (*). Idatha ebalulekileyo (uvavanyo lwe-t, p < 0.05) iphawulwe nge-asterisk (*). Значимые данные (t-критерий, p < 0,05) отмечены звездочкой (*). Idatha ebalulekileyo (uvavanyo lwe-t, p < 0.05) iphawulwe nge-asterisk (*).重要数据（t 检验，p <0.05）用星号(*) 标记。重要数据（t 检验，p <0.05）用星号(*) 标记。 Важные данные (t-test, p < 0,05) отмечены звездочкой (*). Idatha ebalulekileyo (uvavanyo lwe-t, p < 0.05) iphawulwe nge-asterisk (*).Iintolo ezibomvu zibonisa ukupheliswa kokukhuthaza okuthintelayo.
Kwelinye icala, ubuninzi obuphantsi be-Nb4C3TX bubonakalise ukuba buyingozi ngakumbi, kodwa bungadluli kwi-7%. Njengoko bekulindelekile, siqaphele ukuba i-MXenes yayinobuthi obuphezulu kunye nokuthintela ukukhula kwe-microalgae kwi-100mg L-1. Okunomdla kukuba, akukho nanye kwezi zinto ibonise ukuxhomekeka okufanayo kunye nexesha leziphumo zetyhefu/zetyhefu xa kuthelekiswa neesampuli ze-MAX okanye ze-ML (jonga i-SI ukuze ufumane iinkcukacha). Ngelixa kwisigaba se-MAX (jonga uMzobo S3) ubuthi bufikelele malunga ne-15-25% kwaye banda ngokuhamba kwexesha, ukuguquka okuchaseneyo kwabonwa kwi-SL Nb2CTx kunye ne-Nb4C3TX MXene. Ukuthintela ukukhula kwe-microalgae kwehla ngokuhamba kwexesha. Kufikelele malunga ne-17% emva kweeyure ezingama-24 kwaye kwehle ukuya ngaphantsi kwe-5% emva kweeyure ezingama-72 (Umzobo 3a, b, ngokulandelanayo).
Okubaluleke ngakumbi, kwi-SL Nb4C3TX, ukuthintelwa kokukhula kwe-microalgae kufikelele malunga ne-27% emva kweeyure ezingama-24, kodwa emva kweeyure ezingama-72 kwehle ukuya malunga ne-1%. Ke ngoko, sibhale isiphumo esibonwe njengokuthintela okuchaseneyo kokukhuthazwa, kwaye isiphumo sasinamandla kwi-SL Nb4C3TX MXene. Ukukhuthazwa kokukhula kwe-microalgae kuqatshelwe ngaphambili nge-Nb4C3TX (ukusebenzisana kwi-10 mg L-1 iiyure ezingama-24) xa kuthelekiswa ne-SL Nb2CTx MXene. Isiphumo sokuguqula ukuthintelwa nokukhuthaza siboniswe kakuhle kwi-biomass doubling rate curve (jonga uMzobo S4 ngeenkcukacha). Okwangoku, kuphela ubuthi be-ecotoic be-Ti3C2TX MXene obufundwe ngeendlela ezahlukeneyo. Ayinabungozi kwi-zebrafish embryos44 kodwa inobuthi obuphakathi kwi-microalgae Desmodesmus quadricauda kunye ne-Sorghum saccharatum plants45. Eminye imizekelo yeziphumo ezithile ibandakanya ubuthi obuphezulu kwimigca yeeseli zomhlaza kunemigca yeeseli eziqhelekileyo46,47. Kungacingelwa ukuba iimeko zovavanyo ziya kuba nefuthe kutshintsho ekukhuleni kwe-microalgae olubonwa phambi kwe-Nb-MXenes. Umzekelo, i-pH emalunga ne-8 kwi-chloroplast stroma yeyona ifanelekileyo ekusebenzeni kakuhle kwe-enzyme ye-RuBisCO. Ke ngoko, utshintsho lwe-pH luchaphazela kakubi izinga le-photosynthesis48,49. Nangona kunjalo, asizange sibone utshintsho olubalulekileyo kwi-pH ngexesha lovavanyo (jonga i-SI, uMzobo S5 ngeenkcukacha). Ngokubanzi, iinkcubeko ze-microalgae ezine-Nb-MXenes zinciphise kancinci i-pH yesisombululo ngokuhamba kwexesha. Nangona kunjalo, oku kwehla kwakufana notshintsho kwi-pH yesixhobo esicocekileyo. Ukongeza, uluhlu lweenguqu ezifunyenweyo lwalufana nolo lulinganiswe kwinkcubeko ecocekileyo ye-microalgae (isampulu yokulawula). Ke ngoko, sigqiba kwelokuba i-photosynthesis ayichaphazeleki lutshintsho kwi-pH ngokuhamba kwexesha.
Ukongeza, ii-MXenes ezenziweyo zineziphelo zomphezulu (ezibizwa ngokuba yi-Tx). Ezi ngamaqela asebenzayo ikakhulu -O, -F kunye no-OH. Nangona kunjalo, ikhemistri yomphezulu inxulumene ngokuthe ngqo nendlela yokwenza izinto. La maqela ayaziwa ukuba asasazwa ngokungacwangciswanga phezu komphezulu, okwenza kube nzima ukuqikelela isiphumo sawo kwiipropati ze-MXene50. Kungaphikiswana ukuba i-Tx inokuba ngamandla okubangela i-oxidation ye-niobium ngokukhanya. Amaqela asebenzayo kumphezulu ngokwenene abonelela ngeendawo ezininzi zokubambelela kwii-photocatalysts zawo ezingaphantsi ukuze zenze ii-heterojunctions51. Nangona kunjalo, ukwakheka kwe-growth medium akuzange kubonelele nge-photocatalyst esebenzayo (ukwakheka kwe-medium eneenkcukacha kunokufumaneka kwi-SI Table S6). Ukongeza, naluphi na utshintsho kumphezulu nako kubaluleke kakhulu, njengoko umsebenzi webhayoloji we-MXenes unokutshintshwa ngenxa yokulungiswa kweleya emva kokulungiswa, i-oxidation, ukuguqulwa komphezulu weekhemikhali zeekhompawundi ze-organic kunye ne-inorganic52,53,54,55,56 okanye ubunjineli be-surface charge38. Ngoko ke, ukuze kuvavanywe ukuba ingaba i-niobium oxide inento yokwenza nokungazinzi kwezinto ezikhoyo kwi-medium, senze uphando nge-zeta (ζ) potential kwi-microalgae growth medium kunye namanzi acocekileyo (ukuze sithelekise). Iziphumo zethu zibonisa ukuba i-SL Nb-MXenes izinzile (jonga i-SI Fig. S6 kwiziphumo ze-MAX kunye ne-ML). I-zeta potential ye-SL MXenes imalunga ne--10 mV. Kwimeko ye-SR Nb2CTx, ixabiso le-ζ lingaphezulu kancinci kunele-Nb4C3Tx. Utshintsho olunjalo kwixabiso le-ζ lunokubonisa ukuba umphezulu wee-nanoflakes ze-MXene ezitshajiweyo kakubi ufunxa ii-ion ezitshajiweyo kakuhle kwi-culture medium. Ukulinganiswa kwexesha kwe-zeta potential kunye ne-conductivity ye-Nb-MXenes kwi-culture medium (jonga iMifanekiso S7 kunye ne-S8 kwi-SI ukuze ufumane iinkcukacha ezithe vetshe) kubonakala ngathi kuxhasa ingcamango yethu.
Nangona kunjalo, zombini ii-Nb-MXene SL zibonise utshintsho oluncinci ukusuka kwi-zero. Oku kubonisa ngokucacileyo ukuzinza kwazo kwindawo yokukhula kwe-microalgae. Ukongeza, sivavanye ukuba ubukho be-microalgae yethu eluhlaza buya kuyichaphazela na ukuzinza kwe-Nb-MXenes kwindawo yokukhula. Iziphumo ze-zeta potential kunye ne-conductivity ye-MXenes emva kokusebenzisana ne-microalgae kwi-nutrient media kunye nenkcubeko ngokuhamba kwexesha zinokufumaneka kwi-SI (Imifanekiso S9 kunye ne-S10). Okunomdla kukuba, siqaphele ukuba ubukho be-microalgae bubonakala buzinzisa ukusasazeka kwe-MXenes zombini. Kwimeko ye-Nb2CTx SL, i-zeta potential yehle kancinci ngokuhamba kwexesha ukuya kwixabiso elibi ngakumbi (-15.8 ngokuchasene ne--19.1 mV emva kweeyure ezingama-72 zokufunxwa). I-zeta potential ye-SL Nb4C3TX yanda kancinci, kodwa emva kweeyure ezingama-72 yabonisa ukuzinza okuphezulu kune-nanoflakes ngaphandle kobukho be-microalgae (-18.1 vs. -9.1 mV).
Sikwafumanise ukuba izisombululo ze-Nb-MXene azikho lula xa kukho i-microalgae, nto leyo ebonisa ukuba kukho inani elincinci lee-ions kwindawo yezakhamzimba. Okuphawulekayo kukuba, ukungazinzi kwe-MXenes emanzini kubangelwa kakhulu yi-oxidation yomphezulu57. Ke ngoko, sicinga ukuba i-microalgae eluhlaza ngandlela thile yasusa ii-oxides ezenziwe kumphezulu we-Nb-MXene yaze yathintela ukwenzeka kwazo (i-oxidation ye-MXene). Oku kunokubonwa ngokufunda iintlobo zezinto ezifunxwa yi-microalgae.
Nangona izifundo zethu ze-ecotoxicological zibonise ukuba ii-microalgae zikwazile ukoyisa ubuthi be-Nb-MXenes ngokuhamba kwexesha kunye nokuthintela okungaqhelekanga kokukhula okukhuthazwayo, injongo yophando lwethu yayikukuphanda iindlela ezinokwenzeka zokusebenza. Xa izinto eziphilayo ezifana ne-algae zivezwa kwiikhompawundi okanye izinto ezingaziwayo kwiinkqubo zazo zendalo, zinokusabela ngeendlela ezahlukeneyo58,59. Xa kungekho zi-oxide zesinyithi ezinobuthi, ii-microalgae zinokuzondla, zivumele ukuba zikhule ngokuqhubekayo60. Emva kokungenwa kwezinto ezinobuthi, iindlela zokuzikhusela zingasetyenziswa, njengokutshintsha imo okanye imo. Amathuba okufunxa nawo kufuneka aqwalaselwe58,59. Okuphawulekayo kukuba, naluphi na uphawu lwendlela yokuzikhusela luphawu olucacileyo lobuthi bekhompawundi yovavanyo. Ke ngoko, kumsebenzi wethu oqhubekayo, siphande ukusebenzisana okunokwenzeka komphezulu phakathi kwee-nanoflakes ze-SL Nb-MXene kunye ne-microalgae yi-SEM kunye nokufunxwa okunokwenzeka kwe-MXene esekwe kwi-Nb yi-X-ray fluorescence spectroscopy (XRF). Qaphela ukuba uhlalutyo lwe-SEM kunye ne-XRF lwenziwe kuphela kuxinzelelo oluphezulu lwe-MXene ukujongana nemiba yobuthi bomsebenzi.
Iziphumo ze-SEM ziboniswe kwiFig.4. Iiseli ze-microalgae ezinganyangwanga (jonga uMfanekiso 4a, isampuli yesalathiso) zibonise ngokucacileyo imo ye-R. subcapitata eqhelekileyo kunye nemilo yeseli efana ne-croissant. Iiseli zibonakala zithe tyaba kwaye zingacwangciswanga kakuhle. Ezinye iiseli ze-microalgae zadibana kwaye zadibana, kodwa oku mhlawumbi kwakubangelwa yinkqubo yokulungiselela isampuli. Ngokubanzi, iiseli ze-microalgae ezicocekileyo zazinomphezulu ogudileyo kwaye azizange zibonise naluphi na utshintsho lwemo.
Imifanekiso ye-SEM ebonisa ukusebenzisana komphezulu phakathi kwe-microalgae eluhlaza kunye ne-MXene nanosheets emva kweeyure ezingama-72 zokusebenzisana kuxinzelelo oluphezulu (100 mg L-1). (a) I-microalgae eluhlaza enganyangwanga emva kokusebenzisana ne-SL (b) Nb2CTx kunye (c) Nb4C3TX MXenes. Qaphela ukuba ii-Nb-MXene nanoflakes ziphawulwe ngeentolo ezibomvu. Ukuthelekisa, iifoto ezivela kwi-microscope ebonakalayo nazo zongezwa.
Ngokwahlukileyo koko, iiseli ze-microalgae ezifunxwe zii-nanoflakes ze-SL Nb-MXene zonakele (jonga uMzobo 4b, c, iintolo ezibomvu). Kwimeko ye-Nb2CTx MXene (Umzobo 4b), ii-microalgae zikhula ngee-nanoscales ezinamatheleyo ezimbini, ezinokutshintsha imo yazo. Okuphawulekayo kukuba, sikwabone olu tshintsho phantsi kwe-microscopy yokukhanya (jonga uMzobo we-SI S11 ngeenkcukacha). Olu tshintsho lwemo lunesiseko esivakalayo kwi-physiology ye-microalgae kunye nokukwazi kwazo ukuzikhusela ngokutshintsha imo yeseli, njengokunyusa umthamo weseli61. Ke ngoko, kubalulekile ukujonga inani leeseli ze-microalgae ezinxibelelana ne-Nb-MXenes. Izifundo ze-SEM zibonise ukuba malunga ne-52% yeeseli ze-microalgae zazivezwa kwi-Nb-MXenes, ngelixa i-48% yezi seli ze-microalgae zaphepha ukunxibelelana. Kwi-SL Nb4C3Tx MXene, i-microalgae izama ukuphepha ukudibana ne-MXene, ngaloo ndlela ikhula ukusuka kwi-nanoscales ezinemilinganiselo emibini (Umzobo 4c). Nangona kunjalo, asizange sibone ukungena kwe-nanoscales kwiiseli ze-microalgae kunye nomonakalo wazo.
Ukuzigcina kukwayindlela yokuphendula exhomekeke kwixesha xa kuthintelwa i-photosynthesis ngenxa yokufunxwa kwamasuntswana kumphezulu weseli kunye nesiphumo esibizwa ngokuba yi-shading (shading) effect62. Kucacile ukuba into nganye (umzekelo, ii-nanoflakes ze-Nb-MXene) eziphakathi kwe-microalgae kunye nomthombo wokukhanya inciphisa ubungakanani bokukhanya okufunxwa yi-chloroplasts. Nangona kunjalo, asinamathandabuzo okuba oku kunempembelelo enkulu kwiziphumo ezifunyenweyo. Njengoko kubonisiwe kukubona kwethu nge-microscopic, ii-nanoflakes ze-2D azizange zisongelwe ngokupheleleyo okanye zinamathele kumphezulu we-microalgae, nokuba ii-microalgae cells zazinxibelelana ne-Nb-MXenes. Endaweni yoko, ii-nanoflakes zajika zajoliswa kwii-microalgae cells ngaphandle kokugubungela umphezulu wazo. Iseti enjalo yee-nanoflakes/microalgae ayinakunciphisa kakhulu ubungakanani bokukhanya okufunxwa zii-microalgae cells. Ngaphezu koko, ezinye izifundo zibonakalise ukuphucuka kokufunxwa kokukhanya zizinto eziphilayo ze-photosynthetic xa kukho izinto ezi-nanomaterials ezinemilinganiselo emibini63,64,65,66.
Ekubeni imifanekiso ye-SEM ingazange ikwazi ukuqinisekisa ngokuthe ngqo ukufunxwa kwe-niobium ziiseli ze-microalgae, uphando lwethu olongezelelweyo lujike kuhlalutyo lwe-X-ray fluorescence (XRF) kunye ne-X-ray photoelectron spectroscopy (XPS) ukuze kucaciswe le ngxaki. Ke ngoko, sithelekise ubunzulu beencochoyi ze-Nb zeesampulu ze-microalgae ezisetyenzisiweyo ezingadibananga ne-MXenes, ii-MXene nanoflakes ezisuswe kumphezulu weeseli ze-microalgae, kunye neeseli ze-microalgal emva kokususwa kwee-MXenes eziqhotyoshelweyo. Kubalulekile ukuqaphela ukuba ukuba akukho ukufunxwa kwe-Nb, ixabiso le-Nb elifunyenwe ziiseli ze-microalgae kufuneka libe yi-zero emva kokususwa kwee-nanoscales eziqhotyoshelweyo. Ke ngoko, ukuba ukufunxwa kwe-Nb kwenzeka, zombini iziphumo ze-XRF kunye ne-XPS kufuneka zibonise incochoyi ye-Nb ecacileyo.
Kwimeko ye-XRF spectra, iisampulu ze-microalgae zibonise iincopho ze-Nb ze-SL Nb2CTx kunye ne-Nb4C3Tx MXene emva kokusebenzisana ne-SL Nb2CTx kunye ne-Nb4C3Tx MXene (jonga uMfanekiso 5a, qaphela nokuba iziphumo ze-MAX kunye ne-ML MXenes ziboniswe kwi-SI, Imizekeliso S12–C17). Okunomdla kukuba, ubunzulu bencopho ye-Nb buyafana kuzo zombini iimeko (iibha ezibomvu kwiMzekeliso 5a). Oku kubonise ukuba i-algae ayinakukwazi ukufunxa i-Nb engaphezulu, kwaye amandla aphezulu okuqokelela i-Nb afunyenwe kwiiseli, nangona i-Nb4C3Tx MXene ephindwe kabini yayinamathele kwiiseli ze-microalgae (iibha eziluhlaza kwiMzekeliso 5a). Okuphawulekayo kukuba, amandla e-microalgae okufunxa iintsimbi axhomekeke kuxinzelelo lwee-oxide zesinyithi kwindawo67,68. USamshada et al.67 bafumanise ukuba amandla okufunxa amanzi acocekileyo algae ayancipha xa i-pH isanda. URaize nabanye.68 baqaphele ukuba amandla olwandle okufunxa iintsimbi ayephezulu ngama-25% kwiPb2+ kunakwiNi2+.
(a) Iziphumo ze-XRF zokuthathwa kwe-basal Nb ziiseli ze-microalgae eziluhlaza ezifakwe kwi-concentration ephezulu ye-SL Nb-MXenes (100 mg L-1) iiyure ezingama-72. Iziphumo zibonisa ubukho be-α kwiiseli ze-microalgae ezicocekileyo (isampulu yokulawula, iikholamu ezingwevu), ii-nanoflakes ze-2D ezihlukaniswe kwiiseli ze-microalgae ezingaphezulu (iikholamu eziluhlaza okwesibhakabhaka), kunye neeseli ze-microalgae emva kokwahlulwa kwee-nanoflakes ze-2D kumphezulu (iikholamu ezibomvu). Ubungakanani be-elemental Nb, (b) ipesenti yokwakheka kweekhemikhali zezinto eziphilayo ze-microalgae (C=O kunye ne-CHx/C–O) kunye nee-Nb oxides ezikhoyo kwiiseli ze-microalgae emva kokufakwa kwi-SL Nb-MXenes, (c–e) Ukufakwa kwencochoyi ye-compositional ye-XPS SL Nb2CTx spectra kunye (fh) SL Nb4C3Tx MXene efakwe ngaphakathi ziiseli ze-microalgae.
Ngoko ke, besilindele ukuba i-Nb inokufunxwa ziiseli ze-algal ngendlela yee-oxides. Ukuvavanya oku, senze izifundo ze-XPS kwi-MXenes Nb2CTx kunye ne-Nb4C3TX kunye neeseli ze-algae. Iziphumo zokunxibelelana kwe-microalgae ne-Nb-MXenes kunye ne-MXenes ezahlulwe kwiiseli ze-algae ziboniswe kwiMifanekiso 5b. Njengoko bekulindelekile, sifumene iincopho ze-Nb 3d kwiisampulu ze-microalgae emva kokususwa kwe-MXene kumphezulu we-microalgae. Ukuqinisekiswa kobungakanani be-C=O, CHx/CO, kunye ne-Nb oxides kubalwe ngokusekelwe kwi-Nb 3d, O 1s, kunye ne-C 1s spectra efunyenwe nge-Nb2CTx SL (Umzobo 5c–e) kunye ne-Nb4C3Tx SL (Umzobo 5c–e). ) efunyenwe kwi-microalgae efakwe kwi-incubated. Umfanekiso 5f–h) MXenes. Itheyibhile S1-3 ibonisa iinkcukacha zeeparameter ze-peak kunye nekhemistri iyonke ephuma ekulinganeni. Kuyaphawuleka ukuba iindawo ze-Nb 3d ze-Nb2CTx SL kunye ne-Nb4C3Tx SL (Umzobo 5c, f) zihambelana nenxalenye enye ye-Nb2O5. Apha, asifumananga zincochoyi ezinxulumene ne-MXene kwi-spectra, nto leyo ebonisa ukuba iiseli ze-microalgae zifunxa kuphela uhlobo lwe-oxide lwe-Nb. Ukongeza, siqikelele i-C1 s spectrum kunye neenxalenye ze-C–C, CHx/C–O, C=O, kunye ne-–COOH. Sinike iincochoyi ze-CHx/C–O kunye ne-C=O kwigalelo le-organic leeseli ze-microalgae. Ezi nxalenye ze-organic zithatha i-36% kunye ne-41% yeencochoyi ze-C1s kwi-Nb2CTx SL kunye ne-Nb4C3TX SL, ngokwahlukeneyo. Emva koko sifake ii-spectra ze-O1s ze-SL Nb2CTx kunye ne-SL Nb4C3TX kunye ne-Nb2O5, iinxalenye ze-organic ze-microalgae (CHx/CO), kunye namanzi afakwe kumphezulu.
Okokugqibela, iziphumo ze-XPS zibonise ngokucacileyo uhlobo lwe-Nb, kungekuphela nje ukuba ikhona. Ngokwendawo yesignali ye-Nb 3d kunye neziphumo zokususwa kwe-conconvolution, siyaqinisekisa ukuba i-Nb ifunxwa kuphela ngohlobo lwee-oxides kwaye kungekhona ii-ions okanye i-MXene ngokwayo. Ukongeza, iziphumo ze-XPS zibonise ukuba iiseli ze-microalgae zinamandla amakhulu okufunxa ii-Nb oxides kwi-SL Nb2CTx xa kuthelekiswa ne-SL Nb4C3TX MXene.
Nangona iziphumo zethu zokuthathwa kwe-Nb zimangalisa kwaye zisivumela ukuba sibone ukuwohloka kwe-MXene, akukho ndlela ifumanekayo yokulandelela utshintsho oluhambelanayo lwe-morphological kwii-nanoflakes ze-2D. Ke ngoko, sigqibe ekubeni siphuhlise indlela efanelekileyo enokuphendula ngokuthe ngqo kuyo nayiphi na inguqu eyenzekayo kwii-nanoflakes ze-2D Nb-MXene kunye neeseli ze-microalgae. Kubalulekile ukuqaphela ukuba sicinga ukuba ukuba iintlobo ezisebenzisanayo zifumana naluphi na utshintsho, ukubola okanye ukuqhekeka, oku kufuneka kubonakale ngokukhawuleza njengotshintsho kwiiparameter zesimo, njengobubanzi bendawo ejikelezayo efanayo, ukujikeleza, ububanzi be-Feret, okanye ubude be-Feret. Ekubeni ezi parameter zifanelekile ukuchaza amasuntswana amade okanye ii-nanoflakes ezinemilinganiselo emibini, ukulandelwa kwazo ngohlalutyo olunamandla lwesimo se-particle kuya kusinika ulwazi oluxabisekileyo malunga notshintsho lwe-morphological lwee-nanoflakes ze-SL Nb-MXene ngexesha lokunciphisa.
Iziphumo ezifunyenweyo ziboniswe kuMfanekiso 6. Ukuthelekisa, sikwavavanye isigaba sokuqala se-MAX kunye ne-ML-MXenes (jonga iMifanekiso ye-SI S18 kunye ne-S19). Uhlalutyo olunamandla lwemilo yamasuntswana lubonise ukuba zonke iiparameter zemilo yee-Nb-MXene SL ezimbini zitshintshe kakhulu emva kokusebenzisana ne-microalgae. Njengoko kuboniswe yiparameter yobubanzi bendawo ejikelezayo efanayo (Umfanekiso 6a, b), ubunzulu obuncitshisiweyo benxalenye yee-nanoflakes ezinkulu bubonisa ukuba zidla ngokubola zibe ziingceba ezincinci. Kumfanekiso 6c, u-d ubonisa ukwehla kweencopho ezinxulumene nobukhulu obunqamlezileyo bee-flakes (ukunwebeka kwee-nanoflakes), okubonisa ukuguqulwa kwee-nanoflakes ze-2D zibe yimo efana ne-particle. Umfanekiso 6e-h ubonisa ububanzi kunye nobude be-Feret, ngokulandelelana. Ububanzi kunye nobude be-Feret ziiparameter ezihambelanayo kwaye ke ngoko kufuneka ziqwalaselwe kunye. Emva kokufakelwa kwee-nanoflakes ze-2D Nb-MXene phambi kwe-microalgae, iincopho zazo zokunxibelelana kwe-Feret zatshintsha kwaye ubunzulu bazo bancipha. Ngokusekelwe kwezi ziphumo kunye ne-morphology, i-XRF kunye ne-XPS, sigqibe kwelokuba utshintsho olubonweyo lunxulumene kakhulu ne-oxidation njengoko ii-MXenes ezi-oxidized ziba nemibimbi ngakumbi kwaye zahlukana zibe ziingceba kunye namaqhekeza e-oxide angqukuva69,70.
Uhlalutyo lotshintsho lweMXene emva kokusebenzisana ne-microalgae eluhlaza. Uhlalutyo lwemilo yamasuntswana aguqukayo luqwalasela iiparameter ezifana (a, b) ububanzi bendawo ejikelezileyo efanayo, (c, d) ukujikeleza, (e, f) ububanzi be-Feret kunye (g, h) ubude be-Feret. Ngenxa yoku, iisampulu ezimbini ze-microalgae ezisetyenzisiweyo zahlalutywa kunye ne-SL Nb2CTx yokuqala kunye ne-SL Nb4C3Tx MXenes, i-SL Nb2CTx kunye ne-SL Nb4C3Tx MXenes, i-microalgae eyonakeleyo, kunye ne-microalgae enyangiweyo i-SL Nb2CTx kunye ne-SL Nb4C3Tx MXenes. Iintolo ezibomvu zibonisa utshintsho lweeparameter zemilo yee-nanoflakes ezimbini ezifundwayo.
Ekubeni uhlalutyo lweeparamitha zemilo luthembekile kakhulu, lunokubonisa utshintsho lwemo kwiiseli ze-microalgae. Ke ngoko, sihlalutye ububanzi bendawo ejikelezileyo, ukujikeleza, kunye nobubanzi/ubude beFeret beeseli ze-microalgae ezicocekileyo kunye neeseli emva kokusebenzisana nee-nanoflakes ze-2D Nb. Kwifig. 6a–h sibonisa utshintsho kwiiparamitha zemilo yeeseli ze-algae, njengoko kungqinwa kukwehla kobunzulu bencochoyi kunye nokutshintsha kwe-maxima ukuya kumaxabiso aphezulu. Ngokukodwa, iiparamitha ze-cell roundness zibonise ukwehla kweeseli ezinde kunye nokwanda kweeseli ezijikelezayo (Fig. 6a, b). Ukongeza, ububanzi beeseli zeFeret bunyuke ngee-micrometers ezininzi emva kokusebenzisana ne-SL Nb2CTx MXene (Fig. 6e) xa kuthelekiswa ne-SL Nb4C3TX MXene (Fig. 6f). Sikrokrela ukuba oku kusenokuba kungenxa yokufunxwa ngamandla kwee-Nb oxides yi-microalgae xa usebenzisana ne-Nb2CTx SR. Ukuncamatheliswa okungaqinanga kwee-Nb flakes kumphezulu wazo kunokubangela ukukhula kweeseli ngesiphumo esincinci somthunzi.
Ukuqwalasela kwethu utshintsho kwiiparameters zemilo kunye nobukhulu be-microalgae kuhambelana nezinye izifundo. I-green algae inokutshintsha imo yayo ngokuphendula kuxinzelelo lwendalo ngokutshintsha ubungakanani beseli, imo okanye imetabolism61. Umzekelo, ukutshintsha ubungakanani beeseli kwenza kube lula ukufunxwa kwezondlo71. Iiseli ezincinci ze-algae zibonisa ukufunxwa kwezondlo okuphantsi kunye nesantya sokukhula esiphazamisekileyo. Ngokwahlukileyo koko, iiseli ezinkulu zidla ngokutya izondlo ezingaphezulu, ezithi emva koko zibekwe ngaphakathi kweeseli72,73. UMachado noSoares bafumanise ukuba i-fungicide triclosan inokunyusa ubungakanani beseli. Bafumene notshintsho olukhulu kwimo ye-algae74. Ukongeza, uYin et al.9 nabo batyhile utshintsho kwimo ye-algae emva kokuvezwa kwi-graphene oxide nanocomposites ezinciphileyo. Ke ngoko, kuyacaca ukuba iiparameter zobungakanani/imilo ezitshintshiweyo ze-microalgae zibangelwa bubukho be-MXene. Ekubeni olu tshintsho kubungakanani kunye nemilo lubonisa utshintsho ekufunxweni kwezondlo, sikholelwa ukuba uhlalutyo lweeparameter zobungakanani kunye nemilo ngokuhamba kwexesha lunokubonisa ukufunxwa kwe-niobium oxide yi-microalgae phambi kwe-Nb-MXenes.
Ngaphezu koko, iiMXenes zinokungcoliswa xa kukho i-algae. UDalai et al.75 baqaphele ukuba imo ye-algae eluhlaza evezwe kwi-nano-TiO2 kunye ne-Al2O376 yayingafani. Nangona izinto esizibonileyo zifana nolu phononongo lwangoku, lubalulekile kuphela kuphononongo lwemiphumo yokulungiswa kwezinto eziphilayo ngokweemveliso zokonakala kwe-MXene xa kukho i-nanoflakes ze-2D kwaye kungekhona ii-nanoparticles. Ekubeni iiMXenes zinokuwohloka zibe zii-metal oxides,31,32,77,78 kusengqiqweni ukucinga ukuba ii-nanoflakes zethu ze-Nb nazo zinokwenza ii-Nb oxides emva kokudibana neeseli ze-microalgae.
Ukuze sichaze ukunciphisa ii-nanoflakes ze-2D-Nb ngokusebenzisa indlela yokubola esekelwe kwinkqubo yokubola, senze izifundo sisebenzisa i-high-resolution transmission electron microscopy (HRTEM) (Umzobo 7a,b) kunye ne-X-ray photoelectron spectroscopy (XPS) (Umzobo 7). 7c-i kunye neetafile S4-5). Zombini ezi ndlela zifanelekile ekufundeni i-oxidation yezinto ze-2D kwaye ziyahambelana. I-HRTEM iyakwazi ukuhlalutya ukuwohloka kwezakhiwo ezinee-layered ezimbini kunye nokubonakala okulandelayo kwee-nanoparticles ze-metal oxide, ngelixa i-XPS inovelwano kwiibhondi zomphezulu. Ngenxa yesi sizathu, sivavanye ii-nanoflakes ze-2D Nb-MXene ezikhutshwe kwi-microalgae cell dispersions, oko kukuthi, imo yazo emva kokusebenzisana nee-microalgae cells (jonga uMfanekiso 7).
Imifanekiso ye-HRTEM ebonisa imo ye-oxidized (a) SL Nb2CTx kunye (b) SL Nb4C3Tx MXenes, iziphumo zohlalutyo lwe-XPS ezibonisa (c) ukwakheka kweemveliso ze-oxide emva kokunciphisa, (d–f) ukuhambelana kwencopho yeenxalenye ze-XPS spectra ye-SL Nb2CTx kunye ne-(g– i) Nb4C3Tx SL elungisiweyo nge-microalgae eluhlaza.
Izifundo ze-HRTEM ziqinisekisile ukubola kweentlobo ezimbini zee-nanoflakes ze-Nb-MXene. Nangona ii-nanoflakes zigcine imo yazo enemilinganiselo emibini ukuya kwinqanaba elithile, ukubola kubangele ukubonakala kwee-nanoparticles ezininzi ezigubungela umphezulu wee-nanoflakes ze-MXene (jonga uMzobo 7a,b). Uhlalutyo lwe-XPS lwezibonakaliso ze-c Nb 3d kunye ne-O 1s lubonise ukuba ii-Nb oxides zenziwe kuzo zombini iimeko. Njengoko kubonisiwe kuMzobo 7c, i-2D MXene Nb2CTx kunye ne-Nb4C3TX zinezibonakaliso ze-Nb 3d ezibonisa ubukho bee-NbO kunye nee-Nb2O5 oxides, ngelixa iimpawu ze-O 1s zibonisa inani leebhondi ze-O–Nb ezinxulumene nokusebenza komphezulu we-2D nanoflake. Siqaphele ukuba igalelo le-Nb oxide liphezulu xa lithelekiswa ne-Nb-C kunye ne-Nb3+-O.
Kwimifanekiso 7g–i ibonisa ii-XPS spectra ze-Nb 3d, C 1s, kunye ne-O 1s SL Nb2CTx (jonga iiFigs. 7d–f) kunye ne-SL Nb4C3TX MXene ezihlukaniswe kwiiseli ze-microalgae. Iinkcukacha zeeparameter ze-Nb-MXenes peak zibonelelwe kwiiTheyibhile S4–5, ngokulandelelana. Siqale sahlalutya ukwakheka kwe-Nb 3d. Ngokungafaniyo ne-Nb efunxwa ziiseli ze-microalgae, kwi-MXene ehlukaniswe kwiiseli ze-microalgae, ngaphandle kwe-Nb2O5, kufunyenwe ezinye izinto. Kwi-Nb2CTx SL, sibone igalelo le-Nb3+-O kwisixa se-15%, ngelixa ezinye ii-spectrum ze-Nb 3d zilawulwa yi-Nb2O5 (85%). Ukongeza, isampuli ye-SL Nb4C3TX iqulethe izinto ze-Nb-C (9%) kunye ne-Nb2O5 (91%). Apha i-Nb-C ivela kwiileya ezimbini ze-atomic zangaphakathi ze-metal carbide kwi-Nb4C3Tx SR. Emva koko simakisha ii-spectra ze-C1s kwiinxalenye ezine ezahlukeneyo, njengoko senze kwiisampuli ezifakwe ngaphakathi. Njengoko bekulindelekile, i-C1s spectrum ilawulwa yi-graphitic carbon, ilandelwa yiminikelo evela kwiinxalenye ze-organic (CHx/CO kunye ne-C=O) ezivela kwiiseli ze-microalgae. Ukongeza, kwi-spectrum ye-O1s, sibone igalelo leentlobo ze-organic zeeseli ze-microalgae, i-niobium oxide, kunye namanzi afakwe kwi-adsorbed.
Ukongeza, siphande ukuba ukuqhekeka kwe-Nb-MXenes kunxulunyaniswa nokuba khona kweentlobo ze-oxygen ezisabelayo (i-ROS) kwi-nutrient medium kunye/okanye kwiiseli ze-microalgae. Ngenxa yesi sizathu, sivavanye amanqanaba e-singlet oxygen (1O2) kwi-culture medium kunye ne-intracellular glutathione, i-thiol esebenza njenge-antioxidant kwi-microalgae. Iziphumo ziboniswe kwi-SI (Imifanekiso S20 kunye ne-S21). Ii-cultures ezine-SL Nb2CTx kunye ne-Nb4C3TX MXenes zibonakaliswe ngokunciphisa inani le-1O2 (jonga uMfanekiso S20). Kwimeko ye-SL Nb2CTx, i-MXene 1O2 incitshisiwe ukuya kuthi ga kwi-83%. Kwii-microalgae cultures ezisebenzisa i-SL, i-Nb4C3TX 1O2 yehle ngakumbi, ukuya kwi-73%. Okunomdla kukuba, utshintsho kwi-1O2 lubonise umkhwa ofanayo nomphumo wokuthintela-ukuvuselela obonwe ngaphambili (jonga uMfanekiso 3). Kungaphikiswana ukuba ukufukamela ekukhanyeni okukhanyayo kunokutshintsha i-photooxidation. Nangona kunjalo, iziphumo zohlalutyo lolawulo zibonise amanqanaba aphantse abe yi-1O2 ngexesha lovavanyo (Umzobo S22). Kwimeko yamanqanaba e-ROS angaphakathi kwiseli, sikwabone ukuhla okufanayo (jonga uMfanekiso S21). Ekuqaleni, amanqanaba e-ROS kwiiseli ze-microalgae ezikhuliswe phambi kokuba kukho i-Nb2CTx kunye ne-Nb4C3Tx SLs adlule amanqanaba afunyenwe kwiinkcubeko ezicocekileyo ze-microalgae. Ekugqibeleni, nangona kunjalo, kwabonakala ukuba i-microalgae yaziqhelanisa nokuba khona kwe-Nb-MXenes zombini, njengoko amanqanaba e-ROS ehla ukuya kwi-85% kunye ne-91% yamanqanaba alinganiswa kwiinkcubeko ezicocekileyo ze-microalgae ezifakwe i-SL Nb2CTx kunye ne-Nb4C3TX, ngokwahlukeneyo. Oku kunokubonisa ukuba i-microalgae iziva ikhululekile ngakumbi ngokuhamba kwexesha xa kukho i-Nb-MXene kunakwindawo enesondlo kuphela.
IiMicroalgae liqela elahlukileyo lezinto eziphilayo ezisebenzisa i-photosynthesis. Ngexesha le-photosynthesis, ziguqula i-carbon dioxide esemoyeni (CO2) ibe yi-organic carbon. Iimveliso ze-photosynthesis yiglucose kunye ne-oxygen79. Sicinga ukuba i-oxygen eyenziwe ngaloo ndlela idlala indima ebalulekileyo kwi-oxidation ye-Nb-MXenes. Enye ingcaciso enokubakho yoku kukuba i-differential aeration parameter yenziwa kwiingcinezelo eziphantsi neziphezulu ze-oxygen ngaphandle nangaphakathi kwee-nanoflakes ze-Nb-MXene. Oku kuthetha ukuba naphi na apho kukho iindawo zeengcinezelo ezahlukeneyo ze-oxygen, indawo enenqanaba eliphantsi iya kwenza i-anode 80, 81, 82. Apha, ii-microalgae zinegalelo ekudalweni kweeseli ezisebenzisa umoya ngokwahlukileyo kumphezulu wee-MXene flakes, ezivelisa i-oxygen ngenxa yeempawu zazo ze-photosynthesis. Ngenxa yoko, iimveliso ze-biocorrosion (kule meko, ii-niobium oxides) ziyadalwa. Enye into kukuba i-microalgae inokuvelisa ii-organic acids ezikhutshwa emanzini83,84. Ke ngoko, indawo enobundlongondlongo iyadalwa, ngaloo ndlela itshintsha ii-Nb-MXenes. Ukongeza, i-microalgae inokutshintsha i-pH yendalo esingqongileyo ibe yi-alkaline ngenxa yokufunxwa kwe-carbon dioxide, nto leyo enokubangela ukubola79.
Okubaluleke ngakumbi, i-photoperiod emnyama/yokukhanya esetyenzisiweyo kwisifundo sethu ibalulekile ekuqondeni iziphumo ezifunyenweyo. Le nkalo ichazwe ngokweenkcukacha kwi-Djemai-Zoghlache et al. 85 Basebenzise ngabom i-photoperiod yeeyure ezili-12/12 ukubonisa i-biocorrosion enxulunyaniswa ne-biofouling yi-red microalgae Porphyridium purpureum. Babonisa ukuba i-photoperiod inxulunyaniswa nokuguquka kwe-potential ngaphandle kwe-biocorrosion, ezibonakalisa njenge-pseudoperiodic oscillations malunga ne-24:00. Ezi ngqwalasela ziqinisekiswe nguDowling et al. 86 Babonise i-photosynthetic biofilms ye-cyanobacteria i-Anabaena. I-oksijini enyibilikisiweyo yenziwa phantsi kwesenzo sokukhanya, esinxulunyaniswa notshintsho okanye ukuguquguquka kwi-free biocorrosion potential. Ukubaluleka kwe-photoperiod kugxininiswa yinto yokuba i-free potential ye-biocorrosion iyanda kwi-light phase kwaye iyancipha kwi-dark phase. Oku kungenxa yeoksijini eveliswa yi-photosynthetic microalgae, echaphazela impendulo ye-cathodic ngoxinzelelo olungaphelelanga oluveliswa kufutshane nee-electrodes87.
Ukongeza, i-Fourier transform infrared spectroscopy (FTIR) yenziwe ukuze kufunyanwe ukuba kukho utshintsho oluye lwenzeka kwi-chemical composition yee-microalgae cells emva kokusebenzisana ne-Nb-MXenes. Ezi ziphumo zifunyenweyo ziyinkimbinkimbi kwaye sizibonisa kwi-SI (Imifanekiso S23-S25, kuquka iziphumo zesigaba se-MAX kunye ne-ML MXenes). Ngamafutshane, ii-reference spectra ezifunyenweyo ze-microalgae zisinika ulwazi olubalulekileyo malunga neempawu ze-chemical zezi zinto eziphilayo. Ezi ntshukumo zinokwenzeka kakhulu zifumaneka kwi-frequency ye-1060 cm-1 (CO), 1540 cm-1, 1640 cm-1 (C=C), 1730 cm-1 (C=O), 2850 cm-1, 2920 cm-1. enye. 1 1 (C–H) kunye ne-3280 cm–1 (O–H). Kwi-SL Nb-MXenes, sifumene uphawu lwe-CH-bond stretching oluhambelana nophando lwethu lwangaphambili38. Nangona kunjalo, sibonile ukuba ezinye iincopho ezongezelelweyo ezinxulumene neebhondi ze-C=C kunye ne-CH zanyamalala. Oku kubonisa ukuba ukwakheka kweekhemikhali ze-microalgae kunokutshintsha kancinci ngenxa yokusebenzisana ne-SL Nb-MXenes.
Xa kucingwa ngotshintsho olunokwenzeka kwi-biochemistry ye-microalgae, ukuqokelelwa kwee-oxides ezingaphiliyo, ezifana ne-niobium oxide, kufuneka kuqwalaselwe kwakhona59. Ibandakanyeka ekuthathweni kweesinyithi ngumphezulu weseli, ukuthuthwa kwazo ziye kwi-cytoplasm, ukudibana kwazo namaqela e-carboxyl angaphakathi kweseli, kunye nokuqokelelwa kwazo kwi-microalgae polyphosphosomes20,88,89,90. Ukongeza, ubudlelwane phakathi kwe-microalgae kunye neesinyithi bugcinwa ngamaqela asebenzayo eeseli. Ngenxa yesi sizathu, ukufunxwa kuxhomekeke kwi-microalgae surface chemistry, eyinkimbinkimbi kakhulu9,91. Ngokubanzi, njengoko kulindelekile, ukwakheka kweekhemikhali ze-microalgae eluhlaza kutshintshe kancinci ngenxa yokufunxwa kwe-Nb oxide.
Okunomdla kukuba, ukuthintelwa kokuqala kwe-microalgae okubonweyo kwatshintsha ngokuhamba kwexesha. Njengoko sibonile, i-microalgae yoyisa utshintsho lokuqala lwendalo kwaye ekugqibeleni yabuyela kumazinga okukhula aqhelekileyo kwaye yanda. Izifundo ze-zeta potential zibonisa uzinzo oluphezulu xa zifakwa kwi-media yezakhamzimba. Ngoko ke, ukusebenzisana komphezulu phakathi kweeseli ze-microalgae kunye ne-Nb-MXene nanoflakes kugcinwe kulo lonke uvavanyo lokunciphisa. Kuhlalutyo lwethu olongezelelweyo, sishwankathela iindlela eziphambili zokusebenza ezisisiseko solu hlobo lokuziphatha olumangalisayo lwe-microalgae.
Ukuqwalaselwa kwe-SEM kubonise ukuba i-microalgae idla ngokunamathela kwi-Nb-MXenes. Sisebenzisa uhlalutyo lomfanekiso oluguquguqukayo, siqinisekisa ukuba esi siphumo sikhokelela ekuguqulweni kwee-nanoflakes ze-Nb-MXene ezinemilinganiselo emibini zibe zii-particles ezingqukuva, ngaloo ndlela sibonisa ukuba ukubola kwee-nanoflakes kunxulunyaniswa ne-oxidation yazo. Ukuvavanya ingcamango yethu, senze uthotho lwezifundo zezinto kunye ne-biochemical. Emva kokuvavanya, ii-nanoflakes zancipha kancinci kancinci zaza zaqhekeka zaba ziimveliso ze-NbO kunye ne-Nb2O5, ezingazange zibe yingozi kwi-microalgae eluhlaza. Sisebenzisa ukujongwa kwe-FTIR, asifumananga tshintsho lubalulekileyo kwi-chemical composition ye-microalgae efakwe phambi kwee-nanoflakes ze-2D Nb-MXene. Sithathela ingqalelo ithuba lokufunxwa kwe-niobium oxide yi-microalgae, senze uhlalutyo lwe-X-ray fluorescence. Ezi ziphumo zibonisa ngokucacileyo ukuba i-microalgae efundwayo itya ii-niobium oxides (NbO kunye ne-Nb2O5), ezingenabungozi kwi-microalgae efundwayo.