Siyabonga ngokuvakashela i-Nature.com.Usebenzisa inguqulo yesiphequluli enosekelo olulinganiselwe lwe-CSS.Ukuze uthole ulwazi olungcono kakhulu, sincoma ukuthi usebenzise isiphequluli esibuyekeziwe (noma ukhubaze i-Compatibility Mode ku-Internet Explorer).Okwamanje, ukuze siqinisekise ukwesekwa okuqhubekayo, sizonikeza isayithi ngaphandle kwezitayela ne-JavaScript.
Ibonisa i-carousel yamaslayidi amathathu ngesikhathi esisodwa.Sebenzisa izinkinobho Ezidlule kanye Nezilandelayo ukuze uhambe kumaslayidi amathathu ngesikhathi, noma sebenzisa izinkinobho zesilayidi ekugcineni ukuze uhambe kuma-slides amathathu ngesikhathi.
Ukuthuthukiswa okusheshayo kwe-nanotechnology kanye nokuhlanganiswa kwayo ekusetshenzisweni kwansuku zonke kungasongela imvelo.Nakuba izindlela eziluhlaza zokucekelwa phansi kwezinto ezingcolisa izinto eziphilayo zisungulwe kahle, ukutholwa kokungcola kwekristalline ye-inorganic kuyinkinga enkulu ngenxa yokuzwela kwabo okuphansi kwe-biotransformation kanye nokuntula ukuqonda ukusebenzisana kwezinto ezibonakalayo nezinto eziphilayo.Lapha, sisebenzisa imodeli ye-2D MXenes ye-inorganic esekelwe ku-Nb ehlanganiswe nendlela elula yokuhlaziya ipharamitha yomumo ukuze silandele umshini we-bioremediation we-2D ceramic nanomaterials nge-green microalgae Raphidocelis subcapitata.Sithole ukuthi ama-microalgae alulaza ama-MXenes asekelwe ku-Nb ngenxa yokusebenzisana okuhlobene nendawo engaphezulu kwe-physico-chemical.Ekuqaleni, ama-MXene nanoflakes anongqimba olulodwa kanye nama-multilayer anamathiselwe ebusweni bolwelwe oluncane, olwanciphisa ukukhula kolwelwe.Kodwa-ke, lapho kusebenzisana isikhathi eside nendawo engaphezulu, i-microalgae i-MXene oxidized nanoflakes futhi yaqhubeka ibolisa ibe yi-NbO ne-Nb2O5.Ngenxa yokuthi lawa ma-oxide awanabo ubuthi kumaseli e-microalgae, asebenzisa i-Nb oxide nanoparticles ngendlela yokumuncwa ephinde ibuyisele ulwelwe oluncane ngemva kwamahora angu-72 okwelashwa kwamanzi.Imiphumela yezakhi ezihlotshaniswa nokumuncwa ibuye ibonakale ekwandeni kwevolumu yeseli, ukuma kwayo okubushelelezi kanye nokushintsha kwezinga lokukhula.Ngokusekelwe kulokhu okutholakele, siphetha ngokuthi ukuba khona kwesikhathi esifushane nesikhathi eside kwama-MXenes asekelwe ku-Nb ezindaweni eziphila emanzini ahlanzekile kungase kubangele imithelela emincane kuphela kwezemvelo.Kuyaphawuleka ukuthi, sisebenzisa ama-nanomaterials anezinhlangothi ezimbili njengamamodeli amasistimu, sibonisa amathuba okulandelela ukuguqulwa komumo ngisho nasezintweni ezisanhlamvu.Sekukonke, lolu cwaningo luphendula umbuzo obalulekile obalulekile mayelana nezinqubo ezihlobene nokusebenzelana komhlaba ezishayela indlela yokwenziwa kabusha kwezinto eziphilayo ze-2D nanomaterials futhi lunikeza isisekelo sezinye izifundo zesikhathi esifushane nezesikhathi eside zomthelela wendawo we-inorganic crystalline nanomaterials.
Ama-Nanomatadium akhiqize intshisekelo enkulu kusukela ekutholweni kwawo, futhi ama-nanotechnologies ahlukahlukene asanda kungena esigabeni sokuqala sesimanje.Ngeshwa, ukuhlanganiswa kwama-nanomaterials kuzinhlelo zokusebenza zansuku zonke kungaholela ekukhishweni ngephutha ngenxa yokulahlwa okungafanele, ukuphatha budedengu, noma ingqalasizinda yokuphepha enganele.Ngakho-ke, kunengqondo ukucabanga ukuthi ama-nanomaterials, okuhlanganisa ama-nanomaterials amabili-dimensional (2D), angadedelwa endaweni yemvelo, ukuziphatha kanye nomsebenzi webhayoloji okungakaqondwa ngokugcwele.Ngakho-ke, akumangazi ukuthi ukukhathazeka nge-ecotoxicity kugxile ekhonweni le-2D nanomaterials lokungena ezinhlelweni zasemanzini2,3,4,5,6.Kulawa ma-ecosystem, amanye ama-nanomaterials e-2D angasebenzisana nezinto eziphilayo ezahlukahlukene kumazinga ahlukene e-trophic, okuhlanganisa nama-microalgae.
I-Microalgae izidalwa zakudala ezitholakala ngokwemvelo emanzini ahlanzekile kanye nemvelo yasolwandle ekhiqiza imikhiqizo ehlukahlukene yamakhemikhali nge-photosynthesis7.Kanjalo, zibalulekile kuma-ecosystems asemanzini8,9,10,11,12 kodwa futhi ziyizinkomba ezizwelayo, ezingabizi futhi ezisetshenziswa kabanzi ze-ecotoxicity13,14.Njengoba amangqamuzana e-microalgae anda ngokushesha futhi asabela ngokushesha ebukhoneni bezinhlanganisela ezihlukahlukene, athembisa ukuthuthukiswa kwezindlela ezihambisana nemvelo zokwelapha amanzi angcolile ngezinto eziphilayo15,16.
Amaseli e-algae angasusa ama-ion we-inorganic emanzini ngokusebenzisa i-biosorption kanye nokuqoqwa17,18.Ezinye izinhlobo ze-algal ezifana ne-Chlorella, i-Anabaena invar, i-Westiellopsis prolifica, i-Stigeoclonium tenue ne-Synechococcus sp.Itholwe ukuthi ithwala futhi yondle ngisho nama-ion ensimbi anobuthi njenge-Fe2+, Cu2+, Zn2+ ne-Mn2+19.Olunye ucwaningo luye lwabonisa ukuthi i-Cu2+, Cd2+, Ni2+, Zn2+ noma Pb2+ ion ikhawulela ukukhula kwe-Scenedesmus ngokushintsha i-cell morphology kanye nokucekela phansi ama-chloroplasts awo20,21.
Izindlela eziluhlaza zokubola kwezinto ezingcolisa izinto eziphilayo kanye nokususwa kwama-ion ensimbi esindayo ziye zadonsa ukunaka kososayensi nonjiniyela emhlabeni jikelele.Lokhu kubangelwa ikakhulukazi ukuthi lezi zinto ezingcolile zicutshungulwa kalula esigabeni se-liquid.Kodwa-ke, ukungcola kwe-crystalline ye-inorganic kubonakala ngokuncibilika kwamanzi okuphansi kanye nokuthinteka okuphansi kwe-biotransformations ehlukahlukene, okubangela ubunzima obukhulu ekulungiseni, futhi inqubekelaphambili encane yenziwe kule ndawo22,23,24,25,26.Ngakho-ke, ukucinga izixazululo ezihambisana nemvelo zokulungiswa kwama-nanomaterials kuhlala kuyindawo eyinkimbinkimbi futhi engahloliwe.Ngenxa yezinga eliphezulu lokungaqiniseki mayelana nemiphumela ye-biotransformation ye-2D nanomaterials, ayikho indlela elula yokuthola izindlela ezingaba khona zokucekelwa phansi kwazo ngesikhathi sokunciphisa.
Kulolu cwaningo, sisebenzise i-microalgae eluhlaza njenge-ejenti esebenzayo ye-aqueous bioremediation yezinto ze-ceramic ezingaphili, kuhlanganiswe nokuqapha okusendaweni kwenqubo yokuwohloka kwe-MXene njengommeleli wezinto ze-ceramic ezingaphili.Igama elithi "MXene" libonisa i-stoichiometry yezinto ezibonakalayo ze-Mn+1XnTx, lapho i-M iyinsimbi yokuguqulwa kwasekuqaleni, i-X iyi-carbon kanye/noma i-nitrogen, i-Tx iyisinqamuli esingaphezulu (isb, -OH, -F, -Cl), kanye ne-n = 1, 2, 3 noma i-427.28.Kusukela ekutholweni kwe-MXenes nguNaguib et al.Izinzwa, ukwelashwa komdlavuza kanye nokuhlunga kwe-membrane 27,29,30.Ukwengeza, ama-MXenes angabhekwa njengezinhlelo ze-2D eziyimodeli ngenxa yokuzinza kwazo okuhle kakhulu kwe-colloidal kanye nokusebenzisana okungenzeka kwebhayoloji31,32,33,34,35,36.
Ngakho-ke, indlela eyakhiwe kulesi sihloko kanye nemibono yethu yocwaningo iboniswa ku-Figure 1. Ngokwalokhu kucatshangelwa, i-microalgae yehlisa i-Nb-based MXenes ibe yizinhlanganisela ezingezona ezinobuthi ngenxa yokusebenzisana okuhlobene nendawo ye-physico-chemical, okuvumela ukubuyiswa okwengeziwe kwe-algae.Ukuhlola le nkolelo-mbono, amalungu amabili omndeni we-carbides yensimbi ye-niobium-based transition yokuqala kanye/noma ama-nitrides (MXenes), okuyi-Nb2CTx ne-Nb4C3TX, akhethiwe.
Indlela yocwaningo kanye nama-hypotheses asekelwe ebufakazini bokutholwa kwe-MXene nge-green microalgae Raphidocelis subcapitata.Sicela uqaphele ukuthi lokhu kumane kuwukumelwa okuhleliwe kokuqagela okusekelwe ebufakazini.Imvelo yechibi iyahluka ngendlela yezakhi ezisetshenziswayo kanye nezimo (isb., umjikelezo wansuku zonke kanye nemikhawulo yemisoco ebalulekile etholakalayo).Idalwe nge-BioRender.com.
Ngakho-ke, ngokusebenzisa i-MXene njengohlelo lwemodeli, sivule umnyango wokucwaninga ngemiphumela ehlukahlukene yezinto eziphilayo engakwazi ukubonwa namanye ama-nanomaterials avamile.Ikakhulukazi, sibonisa ukuthi kungenzeka ukuthi kusetshenziswe i-bioremediation yama-nanomaterials anezinhlangothi ezimbili, njengama-MXenes asekelwe ku-niobium, nge-microalgae Raphidocelis subcapitata.I-Microalgae iyakwazi ukwehlisa i-Nb-MXenes ku-oxides engeyona enobuthi i-NbO ne-Nb2O5, ephinde inikeze imisoco ngokusebenzisa indlela yokuthatha i-niobium.Sekukonke, lolu cwaningo luphendula umbuzo obalulekile obalulekile mayelana nezinqubo ezihambisana nokusebenzisana kwe-surface physicochemical okubusa izindlela ze-bioremediation yama-nanomaterials anezinhlangothi ezimbili.Ngaphezu kwalokho, sakha indlela elula esekwe kupharamitha yokulandelela izinguquko ezicashile ekubunjweni kwama-nanomaterials angu-2D.Lokhu kukhuthaza olunye ucwaningo lwesikhathi esifushane nolwesikhathi eside emithelela ehlukahlukene yemvelo ye-inorganic crystalline nanomaterials.Ngakho-ke, ucwaningo lwethu lukhulisa ukuqonda kokuxhumana phakathi kwezinto ezibonakalayo nezinto eziphilayo.Futhi sihlinzeka ngesisekelo socwaningo olwandisiwe lwesikhathi esifushane kanye nesikhathi eside mayelana nemithelela yazo engaba khona ku-ecosystem yamanzi ahlanzekile, manje engaqinisekiswa kalula.
I-MXenes imelela ikilasi elithakazelisayo lezinto ezinezici ezibonakalayo nezikhangayo eziyingqayizivele futhi ezikhangayo futhi ngenxa yalokho izicelo eziningi ezingase zibe khona.Lezi zakhiwo zincike kakhulu ku-stoichiometry yazo kanye ne-surface chemistry.Ngakho-ke, ocwaningweni lwethu, siphenye izinhlobo ezimbili ze-Nb-based hierarchical single-layer (SL) MXenes, Nb2CTx kanye ne-Nb4C3TX, njengoba imiphumela ehlukene yebhayoloji yalezi nanomatadium ingabonwa.Ama-MXene akhiqizwa kusukela ezintweni zawo zokuqala ngokuqoshwa okukhethayo okusuka phansi kuya phansi kwezingqimba ze-athomu ezincane zesigaba A-MAX.Isigaba se-MAX i-ternary Ceramic esakhiwe amabhulokhi "ahlanganisiwe" we-transition metal carbides kanye nezendlalelo ezincane zama-elementi "A" afana ne-Al, Si, ne-Sn ene-MnAXn-1 stoichiometry.I-morphology yesigaba sokuqala se-MAX yabonwa ngokuskena i-electron microscopy (SEM) futhi yayihambisana nezifundo zangaphambilini (Bheka Ulwazi Olwengeziwe, SI, Umfanekiso S1).I-Multilayer (ML) i-Nb-MXene itholwe ngemva kokukhipha isendlalelo se-Al nge-48% HF (hydrofluoric acid).I-morphology ye-ML-Nb2CTx ne-ML-Nb4C3TX yahlolwa ngokuskena i-electron microscopy (SEM) (Amanani S1c kanye ne-S1d ngokulandelanayo) futhi kwabonwa i-MXene morphology enezingqimba, efana nama-nanoflake anezinhlangothi ezimbili edlula ezimbotsheni ezinde njenge-pore.Womabili ama-Nb-MXenes afana kakhulu nezigaba ze-MXene ezahlanganiswa yi-acid etching27,38.Ngemuva kokuqinisekisa ukwakheka kwe-MXene, siyibeke nge-intercalation ye-tetrabutylammonium hydroxide (TBAOH) elandelwa ukugeza kanye ne-sonication, ngemva kwalokho sithole ungqimba olulodwa noma ungqimba oluphansi (SL) 2D Nb-MXene nanoflakes.
Sisebenzise i-high resolution transmission electron microscopy (HRTEM) kanye ne-X-ray diffraction (XRD) ukuze sihlole ukusebenza kahle kwe-etching nokuqhubeka nokuxebuka.Imiphumela ye-HRTEM ecutshungulwe kusetshenziswa i-Inverse Fast Fourier Transform (IFFT) kanye ne-Fast Fourier Transform (FFT) ikhonjisiwe ku-Fig. 2. Ama-nanoflake e-Nb-MXene ayeqondiswe emaphethelweni ukuze kuhlolwe ukwakheka kwesendlalelo se-athomu nokukala amabanga aphakathi kwe-interplanar.Izithombe ze-HRTEM ze-MXene Nb2CTx ne-Nb4C3TX nanoflakes zembula imvelo yazo enezingqimba ezincane ze-athomu (bona i-Fig. 2a1, a2), njengoba kubikwe ngaphambilini ngu-Naguib et al.27 no-Jastrzębska et al.38.Kuma-monolayers amabili aseduze we-Nb2CTx ne-Nb4C3Tx, sinqume amabanga e-interlayer angu-0.74 no-1.54 nm, ngokulandelanayo (Amakhiwane 2b1,b2), nawo avumelana nemiphumela yethu yangaphambili38.Lokhu kwaqinisekiswa futhi uguquko olusheshayo lwe-Fourier oluphambanayo (Umfanekiso 2c1, c2) kanye noguquko olusheshayo lwe-Fourier (Fig. 2d1, d2) olubonisa ibanga phakathi kwe-Nb2CTx ne-Nb4C3Tx ama-monolayers.Isithombe sibonisa ukushintshana kwamabhande akhanyayo namnyama ahambisana ne-niobium nama-athomu ekhabhoni, okuqinisekisa imvelo egqinsiwe yama-MXenes afundwayo.Kubalulekile ukuqaphela ukuthi i-spectra ye-X-ray ehlakazekayo ye-X-ray (EDX) etholwe i-Nb2CTx ne-Nb4C3Tx (Izibalo S2a ne-S2b) ayizange ibonise insalela yesigaba sokuqala se-MAX, njengoba kungekho ukuphakama kwe-Al okutholiwe.
Ukucaciswa kwe-SL Nb2CTx ne-Nb4C3Tx MXene nanoflakes, okuhlanganisa (a) umbono oseceleni we-electron microscopy (HRTEM) yokucaca okuphezulu kwe-2D nanoflake nokuhambisanayo, (b) imodi yokuqina, (c) inverse fast Fourier transform (IFFT), (d) fast Fourier transform (FFT-MX) amaphethini we-Xb.Ku-SL 2D Nb2CTx, izinombolo zivezwa ngokuthi (a1, b1, c1, d1, e1).Ku-SL 2D Nb4C3Tx, izinombolo zivezwa njengokuthi (a2, b2, c2, d2, e1).
Izilinganiso ze-X-ray diffraction ze-SL Nb2CTx kanye ne-Nb4C3Tx MXenes ziboniswa ku-Fig.2e1 kanye no-e2, ngokulandelana.I-Peaks (002) ku-4.31 kanye ne-4.32 ihambelana ne-MXenes Nb2CTx enengqimba echazwe ngaphambilini kanye ne-Nb4C3TX38,39,40,41 ngokulandelanayo.Imiphumela ye-XRD iphinda ibonise ukuba khona kwezinye izakhiwo ezisele ze-ML nezigaba ezingu-MAX, kodwa ikakhulukazi amaphethini e-XRD ahlotshaniswa ne-SL Nb4C3Tx (Fig. 2e2).Ukuba khona kwezinhlayiya ezincane zesigaba esingu-MAX kungase kuchaze ukuphakama okunamandla okungu-MAX uma kuqhathaniswa nezendlalelo ezistakiwe ezingahleliwe ze-Nb4C3Tx.
Ucwaningo olwengeziwe lugxile olwelweni oluncane oluluhlaza lohlobo lwe-R. subcapitata.Sikhethe ama-microalgae ngoba angabakhiqizi ababalulekile ababandakanyeka kuma-webs okudla amakhulu42.Futhi zingenye yezinkomba ezinhle kakhulu zobuthi ngenxa yekhono lokususa izinto ezinobuthi ezithwalwa emazingeni aphezulu ochungechunge lokudla43.Ukwengeza, ucwaningo lwe-R. subcapitata lungase lukhanyise ngobuthi obungalindelekile be-SL Nb-MXenes kuma-microorganisms avamile wamanzi ahlanzekile.Ukukhombisa lokhu, abacwaningi bacabanga ukuthi i-microbe ngayinye inokuzwela okuhlukile kumakhemikhali anobuthi akhona endaweni.Ezintweni eziningi eziphilayo, ukugxiliswa okuphansi kwezinto akuthinti ukukhula kwazo, kuyilapho ukugxila ngaphezu komkhawulo othile kungazivimbela noma kubangele nokufa.Ngakho-ke, ezifundweni zethu zokusebenzisana okungaphezulu phakathi kwe-microalgae ne-MXenes kanye nokululama okuhambisanayo, sinqume ukuhlola ukugxila okungenangozi nobuthi be-Nb-MXenes.Ukuze senze lokhu, sihlole ukugxila kwe-0 (njengereferensi), i-0.01, 0.1 kanye ne-10 mg l-1 MXene kanye ne-microalgae enegciwane elinokugxila okuphezulu kakhulu kwe-MXene (100 mg l-1 MXene), okungaba ngokwedlulele futhi kubulale..nganoma iyiphi indawo yebhayoloji.
Imiphumela ye-SL Nb-MXenes kuma-microalgae iboniswa kuMfanekiso 3, ovezwa njengephesenti lokukhuthazwa kokukhula (+) noma ukuvimbela (-) okukalwa ngamasampula angu-0 mg l-1.Ukuze uqhathanise, isigaba se-Nb-MAX kanye ne-ML Nb-MXenes nazo zahlolwa futhi imiphumela iboniswa ku-SI (bheka i-Fig. S3).Imiphumela etholiwe iqinisekisile ukuthi i-SL Nb-MXenes cishe ayinakho ngokuphelele ubuthi ebangeni lokugxila okuphansi kusuka ku-0.01 kuya ku-10 mg / l, njengoba kuboniswe ku-Fig. 3a,b.Esimeni se-Nb2CTx, asibonanga i-ecotoxicity engaphezu kuka-5% ebangeni elishiwo.
Ukugqugquzela (+) noma ukuvimbela (-) ukukhula kwe-microalgae phambi kwe-SL (a) Nb2CTx kanye (b) ne-Nb4C3TX MXene.24, 48 kanye namahora angu-72 wokusebenzisana kwe-MXene-microalgae ahlaziywa. Idatha ebalulekile (t-test, p <0.05) imakwe ngenkanyezi (*). Idatha ebalulekile (t-test, p <0.05) imakwe ngenkanyezi (*). Значимые данные (t-критерий, p < 0,05) отмечены звездочкой (*). Idatha ebalulekile (t-test, p <0.05) imakwe ngenkanyezi (*).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 ebalulekile (t-test, p <0.05) imakwe ngenkanyezi (*).Imicibisholo ebomvu ibonisa ukuqedwa kwesikhuthazo esivimbelayo.
Ngakolunye uhlangothi, ukugxila okuphansi kwe-Nb4C3TX kuvele kunobuthi obuthe xaxa, kodwa hhayi ngaphezulu kuka-7%.Njengoba bekulindelekile, sibonile ukuthi i-MXenes inobuthi obuphezulu kanye nokuvimbela ukukhula kwe-microalgae ku-100mg L-1.Kuyathakazelisa ukuthi azikho izinto ezibonisa ithrendi efanayo nokuncika kwesikhathi kwemiphumela enobuthi/ enobuthi uma kuqhathaniswa namasampuli e-MAX noma e-ML (bona i-SI ukuze uthole imininingwane).Ngenkathi esigabeni se-MAX (bona u-Fig. S3) ubuthi bufinyelele cishe ku-15-25% futhi banda ngokuhamba kwesikhathi, ukuthambekela okuphambene kwabonwa ku-SL Nb2CTx ne-Nb4C3TX MXene.Ukuvinjelwa kokukhula kwama-microalgae kwehla ngokuhamba kwesikhathi.Ifinyelele cishe ku-17% ngemva kwamahora angu-24 futhi yehla yaba ngaphansi kuka-5% ngemva kwamahora angu-72 (Fig. 3a, b, ngokulandelana).
Okubaluleke nakakhulu, ku-SL Nb4C3TX, ukuvimbela ukukhula kwama-microalgae kufinyelele cishe ku-27% ngemva kwamahora angu-24, kodwa ngemva kwamahora angu-72 kwehle kwafinyelela cishe ku-1%.Ngakho-ke, sibhale umphumela obhekiwe njengokuvinjelwa okuphambene kokukhuthazwa, futhi umphumela wawunamandla ku-SL Nb4C3TX MXene.Ukukhuthazwa kokukhula kwe-microalgae kwaphawulwa ngaphambili nge-Nb4C3TX (ukusebenzelana ku-10 mg L-1 ngamahora angama-24) uma kuqhathaniswa ne-SL Nb2CTx MXene.Umthelela wokuhlehla we-inhibition-stimulation nawo uboniswe kahle ku-biomass rate curve (bona Fig. S4 ukuze uthole imininingwane).Kuze kube manje, i-ecotoxicity ye-Ti3C2TX MXene kuphela efundwe ngezindlela ezahlukene.Ayinabuthi kuma-zebrafish embryos44 kodwa ine-ecotoxic emaphakathi e-Desmodesmus quadricauda nezitshalo zeSorghum saccharatum45.Ezinye izibonelo zemiphumela ethile zihlanganisa ubuthi obuphezulu emigqeni yamangqamuzana omdlavuza kunemigqa yeseli evamile46,47.Kungacatshangwa ukuthi izimo zokuhlola zingathonya izinguquko ekukhuleni kwe-microalgae ebonwa phambi kwe-Nb-MXenes.Isibonelo, i-pH engaba ngu-8 ku-chloroplast stroma ilungele ukusebenza kahle kwe-enzyme ye-RuBisCO.Ngakho-ke, izinguquko ze-pH zithinta kabi izinga le-photosynthesis48,49.Kodwa-ke, asizange sibone izinguquko ezibalulekile ku-pH phakathi nokuhlolwa (bona i-SI, Fig. S5 ukuze uthole imininingwane).Ngokuvamile, amasiko ama-microalgae ane-Nb-MXenes anciphisa kancane i-pH yesisombululo ngokuhamba kwesikhathi.Kodwa-ke, lokhu kuncipha kwakufana noshintsho ku-pH yendawo ehlanzekile.Ukwengeza, ububanzi bokuhluka okutholakele babufana nalolo olulinganiselwe isiko elihlanzekile le-microalgae (isampula yokulawula).Ngakho, siphetha ngokuthi i-photosynthesis ayithinteki izinguquko ku-pH ngokuhamba kwesikhathi.
Ngaphezu kwalokho, ama-MXenes ahlanganisiwe aneziphetho ezingaphezulu (ezichazwe njenge-Tx).Lawa ngokuyinhloko amaqembu asebenzayo -O, -F kanye -OH.Nokho, i-surface chemistry ihlobene ngokuqondile nendlela yokuhlanganisa.Lawa maqembu aziwa ngokuthi asatshalaliswa ngokungahleliwe phezulu, okwenza kube nzima ukubikezela umphumela wawo kuzakhiwo ze-MXene50.Kungaphikiswana ngokuthi i-Tx ingaba amandla okwenza i-oxidation ye-niobium ngokukhanya.Amaqembu asebenza ngokuphezulu ahlinzeka ngempela ngeziza eziningi zokubambelela kuma-photocatalyst awo angaphansi ukuze akhe i-heterojunctions51.Kodwa-ke, ukwakheka okuphakathi kokukhula akuzange kunikeze i-photocatalyst esebenzayo (ukwakheka okuphakathi okuningiliziwe kungatholakala kuthebula le-SI S6).Ukwengeza, noma yikuphi ukuguqulwa kwendawo nakho kubaluleke kakhulu, njengoba umsebenzi we-biological we-MXenes ungashintshwa ngenxa ye-layer post-processing, i-oxidation, ukuguqulwa kwamakhemikhali ebusweni bezinto eziphilayo kanye ne-inorganic compounds52,53,54,55,56 noma ubunjiniyela be-surface charge38.Ngakho-ke, ukuhlola ukuthi i-niobium oxide ihlobene yini nokungazinzi kwempahla phakathi nendawo, senze izifundo ze-zeta (ζ) okungenzeka ku-microalgae ukukhula okuphakathi namanzi akhishwe yi-deionized (ukuqhathanisa).Imiphumela yethu ibonisa ukuthi i-SL Nb-MXenes izinzile kahle (bona i-SI Fig. S6 yemiphumela engu-MAX ne-ML).Amandla we-zeta we-SL MXenes cishe -10 mV.Esimeni se-SR Nb2CTx, inani elithi ζ lithi liyigebengu kakhulu kunalelo le-Nb4C3Tx.Ushintsho olunjalo enanini elingu-ζ lungase lubonise ukuthi indawo engaphezulu ye-MXene nanoflakes eshajwa kabi imunca ama-ion ashajwe kahle endaweni yesiko.Izilinganiso zesikhashana zekhono le-zeta kanye ne-conductivity ye-Nb-MXenes ku-culture medium (bona Amanani S7 kanye ne-S8 ku-SI ukuze uthole imininingwane eyengeziwe) kubonakala sengathi isekela i-hypothesis yethu.
Kodwa-ke, womabili ama-Nb-MXene SL abonise izinguquko ezincane ukusuka ku-zero.Lokhu kukhombisa ngokusobala ukuzinza kwabo endaweni yokukhula kwama-microalgae.Ngaphezu kwalokho, sihlole ukuthi ukuba khona kwe-microalgae yethu eluhlaza kungathinta ukuzinza kwe-Nb-MXenes phakathi nendawo.Imiphumela yekhono le-zeta kanye ne-conductivity ye-MXenes ngemva kokuxhumana ne-microalgae emithonjeni yezondlo kanye namasiko ngokuhamba kwesikhathi ingatholakala ku-SI (Izibalo S9 kanye ne-S10).Kuyathakazelisa ukuthi saqaphela ukuthi ukuba khona kwe-microalgae kubonakala kuzinzisa ukuhlakazeka kwawo womabili ama-MXenes.Endabeni ye-Nb2CTx SL, amandla e-zeta ancipha ngisho kancane ngokuhamba kwesikhathi kuya kumanani amabi kakhulu (-15.8 uma kuqhathaniswa -19.1 mV ngemva kwamahora angu-72 e-incubation).Amandla we-zeta we-SL Nb4C3TX anda kancane, kodwa ngemva kwe-72 h asabonisa ukuzinza okuphezulu kune-nanoflakes ngaphandle kokuba khona kwe-microalgae (-18.1 vs. -9.1 mV).
Siphinde sathola ukuqhutshwa okuphansi kwezixazululo ze-Nb-MXene ezifakwe phambi kwe-microalgae, ebonisa inani eliphansi lama-ion endaweni yezakhi.Ngokuphawulekayo, ukungazinzi kwe-MXenes emanzini kubangelwa ikakhulukazi i-oxidation yendawo57.Ngakho-ke, sisola ukuthi i-microalgae eluhlaza ngandlela-thile yasusa ama-oxides akhiwe ebusweni be-Nb-MXene futhi yavimbela nokuvela kwawo (i-oxidation ye-MXene).Lokhu kungabonwa ngokutadisha izinhlobo zezinto ezimuncwe ama-microalgae.
Nakuba izifundo zethu ze-ecotoxicological zibonise ukuthi ama-microalgae akwazi ukunqoba ubuthi be-Nb-MXenes ngokuhamba kwesikhathi kanye nokuvinjelwa okungavamile kokukhula okukhuthazwayo, inhloso yocwaningo lwethu kwakuwukuphenya izindlela ezingenzeka zokwenza.Lapho izinto eziphilayo ezinjengolwelwe zichayeka kuzinhlanganisela noma izinto ezingajwayelekile kuma-ecosystem azo, zingase zisabele ngezindlela ezihlukahlukene58,59.Uma engekho ama-oxide ensimbi anobuthi, ama-microalgae angakwazi ukuzondla ngokwawo, okuwavumela ukuba akhule ngokuqhubekayo60.Ngemva kokungenisa izinto ezinobuthi, izindlela zokuzivikela zingase zenziwe zisebenze, njengokushintsha isimo noma isimo.Amathuba okumuncwa nawo kufanele acatshangelwe58,59.Ngokuphawulekayo, noma yiluphi uphawu lwendlela yokuzivikela luyinkomba ecacile yobuthi benhlanganisela yokuhlola.Ngakho-ke, emsebenzini wethu oqhubekayo, siphenye ukuxhumana okungaba khona kwendawo phakathi kwe-SL Nb-MXene nanoflakes kanye ne-microalgae nge-SEM kanye nokumuncwa okungenzeka kwe-Nb-based MXene nge-X-ray fluorescence spectroscopy (XRF).Qaphela ukuthi ukuhlaziya kwe-SEM ne-XRF kwenziwe kuphela ekugxilweni okuphezulu kwe-MXene ukuze kubhekwane nezinkinga zobuthi bomsebenzi.
Imiphumela ye-SEM ikhonjiswe ku-Fig.4.Amaseli e-microalgae angaphenduliwe (bona u-Fig. 4a, isampula yereferensi) abonise ngokucacile i-R. subcapitata morphology kanye nokuma kweseli okufana ne-croissant.Amaseli abonakala eyisicaba futhi engahlelekile ngandlela thize.Amanye amaseli e-microalgae agqagqene futhi abambene, kodwa lokhu kungenzeka kubangelwe inqubo yokulungiselela isampula.Ngokuvamile, amangqamuzana e-microalgae ahlanzekile ayenobuso obushelelezi futhi awazange abonise izinguquko ze-morphological.
Izithombe ze-SEM ezibonisa ukusebenzisana kwendawo phakathi kwe-microalgae eluhlaza kanye nama-nanosheet e-MXene ngemva kwamahora angu-72 okusebenzelana ekugxiliseni okukhulu kakhulu (100 mg L-1).(a) I-microalgae eluhlaza engelashiwe ngemva kokusebenzelana ne-SL (b) Nb2CTx kanye (c) ne-Nb4C3TX MXenes.Qaphela ukuthi ama-nanoflakes e-Nb-MXene amakwe ngemicibisholo ebomvu.Ukuze uqhathanise, izithombe ezivela kusibonakhulu se-optical nazo zengezwa.
Ngokuphambene, amangqamuzana e-microalgae adsorbed yi-SL Nb-MXene nanoflakes wonakaliswa (bheka i-Fig. 4b, c, imicibisholo ebomvu).Endabeni ye-Nb2CTx MXene (Fig. 4b), ama-microalgae avame ukukhula nama-nanoscales anezinhlangothi ezimbili ezinamathiselwe, ezingashintsha i-morphology yazo.Ngokuphawulekayo, siphinde sabona lezi zinguquko ngaphansi kwe-microscopy ekhanyayo (bona umfanekiso we-SI S11 ukuze uthole imininingwane).Lolu shintsho lwe-morphological lunesisekelo esizwakalayo ku-physiology ye-microalgae kanye nekhono labo lokuzivikela ngokushintsha i-cell morphology, njengokwandisa umthamo weseli61.Ngakho-ke, kubalulekile ukuhlola inani lamaseli e-microalgae empeleni axhumene ne-Nb-MXenes.Ucwaningo lwe-SEM lubonise ukuthi cishe i-52% yamaseli e-microalgae avezwe ku-Nb-MXenes, kuyilapho i-48% yalawa maseli e-microalgae agwema ukuthintana.Nge-SL Nb4C3Tx MXene, ama-microalgae azama ukugwema ukuthintana ne-MXene, ngaleyo ndlela enze indawo futhi akhule esuka kuma-nanoscales anezinhlangothi ezimbili (Fig. 4c).Kodwa-ke, asizange sibone ukungena kwe-nanoscales kumaseli we-microalgae kanye nokulimala kwawo.
Ukuzilondoloza nakho kuwukuziphatha kokuphendula okuncike esikhathini ekuvinjweni kwe-photosynthesis ngenxa yokukhangiswa kwezinhlayiya endaweni yeseli kanye nalokho okubizwa ngokuthi i-shading (shading) effect62.Kuyacaca ukuthi into ngayinye (isibonelo, i-Nb-MXene nanoflakes) ephakathi kwe-microalgae kanye nomthombo wokukhanya ikhawulela inani lokukhanya elimuncwa ama-chloroplast.Nokho, asingabazi ukuthi lokhu kunomthelela omkhulu emiphumeleni etholiwe.Njengoba kuboniswe ngokubheka kwethu okuncane, ama-nanoflakes e-2D awazange ahlanganiswe ngokuphelele noma anamathele ebusweni be-microalgae, ngisho nalapho amangqamuzana amancane e-microalgae ehlangene ne-Nb-MXenes.Esikhundleni salokho, ama-nanoflakes aphenduke aqondiswe kumaseli e-microalgae ngaphandle kokumboza indawo yawo.Iqoqo elinjalo lama-nanoflakes/microalgae alikwazi ukukhawulela ngokuphawulekayo inani lokukhanya elimuncwa amaseli ama-microalgae.Ngaphezu kwalokho, ezinye izifundo ziye zabonisa ngisho nokuthuthuka kokumuncwa kokukhanya yizinto eziphilayo ze-photosynthetic phambi kwama-nanomaterials anezinhlangothi ezimbili63,64,65,66.
Njengoba izithombe ze-SEM zingazange ziqinisekise ngokuqondile ukutholwa kwe-niobium ngamaseli e-microalgae, ucwaningo lwethu olwengeziwe luphendukele ku-X-ray fluorescence (XRF) kanye nokuhlaziywa kwe-X-ray photoelectron spectroscopy (XPS) ukuze kucaciswe lolu daba.Ngakho-ke, siqhathanise ukuqina kweziqongo ze-Nb zereferensi yamasampula e-microalgae angazange ahlangane nama-MXenes, ama-MXene nanoflakes akhishwe ebusweni bamaseli ama-microalgae, namaseli amancane ama-microalgal ngemva kokususwa kwe-MXenes enamathiselwe.Kuyaqapheleka ukuthi uma kungekho ukutholwa kwe-Nb, inani le-Nb elitholwe amaseli e-microalgae kufanele libe yi-zero ngemuva kokususwa kwe-nanoscales enamathiselwe.Ngakho-ke, uma ukuthatha kwe-Nb kwenzeka, kokubili imiphumela ye-XRF ne-XPS kufanele ibonise ukuphakama kwe-Nb okucacile.
Endabeni ye-XRF spectra, amasampula e-microalgae abonise iziqongo ze-Nb ze-SL Nb2CTx ne-Nb4C3Tx MXene ngemva kokusebenzelana ne-SL Nb2CTx kanye ne-Nb4C3Tx MXene (bona u-Fig. 5a, futhi phawula ukuthi imiphumela ye-MAX ne-ML MXenes iboniswa ku-SI, Figs 72-12).Kuyathakazelisa ukuthi ukuqina kwe-Nb peak kuyafana kuzo zombili izimo (imigoqo ebomvu ku-Fig. 5a).Lokhu kubonise ukuthi i-algae ayikwazanga ukumunca i-Nb eyengeziwe, futhi umthamo omkhulu wokuqoqwa kwe-Nb ufinyelelwe kumaseli, nakuba izikhathi ezimbili ezingaphezu kwe-Nb4C3Tx MXene zixhunywe kumaseli e-microalgae (imigoqo eluhlaza okwesibhakabhaka ku-Fig. 5a).Ngokuphawulekayo, ikhono le-microalgae lokumunca izinsimbi lincike ekugxilweni kwama-oxide ensimbi endaweni67,68.U-Shamshada et al.67 uthole ukuthi amandla okumuncwa olwelwe lwamanzi ahlanzekile ayehla ngokwenyuka kwe-pH.URaize et al.68 waphawula ukuthi ikhono lokhula lwasolwandle lokumunca izinsimbi cishe laliphezulu ngo-25% ku-Pb2+ kune-Ni2+.
(a) Imiphumela ye-XRF yokuthathwa kwe-basal Nb ngamaseli e-microalgae aluhlaza afakwe ekuhlanganiseni okwedlulele kwe-SL Nb-MXenes (100 mg L-1) amahora angu-72.Imiphumela ibonisa ukuba khona kwe-α kumaseli e-microalgae ahlanzekile (isampula yokulawula, amakholomu ampunga), ama-nanoflakes e-2D ahlukaniswe namaseli e-microalgae angaphezulu (amakholomu aluhlaza okwesibhakabhaka), namaseli ama-microalgae ngemva kokuhlukaniswa kwama-nanoflakes angu-2D ukusuka phezulu (amakholomu abomvu).Inani le-Elemental Nb, (b) iphesenti lokwakheka kwamakhemikhali ezingxenyeni eziphilayo ze-microalgae (C=O ne-CHx/C–O) nama-Nb oxides akhona kumaseli e-microalgae ngemva kokufukamela nge-SL Nb-MXenes, (c–e) Ukufakwa kwenani eliphakeme lokuqamba le-XPS SL Nb2CTx spectra yangaphakathi ye-XPS Nb2CTx SL ne-MXx Nbga3 microscellence (fh4C)
Ngakho-ke, besilindele ukuthi i-Nb ingamuncwa amaseli algal ngendlela yama-oxide.Ukuhlola lokhu, senze izifundo ze-XPS ku-MXenes Nb2CTx ne-Nb4C3TX namaseli e-algae.Imiphumela yokusebenzisana kwe-microalgae ne-Nb-MXenes kanye ne-MXenes ehlukanisiwe namaseli e-algae iboniswa ku-Fig.5b.Njengoba bekulindelekile, sithole iziqongo ze-Nb 3d kumasampula e-microalgae ngemva kokususwa kwe-MXene ebusweni be-microalgae.Ukunqunywa komthamo we-C=O, CHx/CO, kanye ne-Nb oxides kubalwe ngokusekelwe ku-Nb 3d, O 1s, ne-C 1s spectra etholwe nge-Nb2CTx SL (Fig. 5c–e) kanye ne-Nb4C3Tx SL (Fig. 5c–e).) etholwe kuma-microalgae afukamele.Umfanekiso 5f–h) Mxenes.Ithebula S1-3 libonisa imininingwane yamapharamitha aphezulu kanye nekhemistri ephelele ewumphumela wokulingana.Kuyaphawuleka ukuthi izifunda ze-Nb 3d ze-Nb2CTx SL ne-Nb4C3Tx SL (Fig. 5c, f) zihambisana nengxenye eyodwa ye-Nb2O5.Lapha, asitholanga iziqongo ezihlobene ne-MXene ku-spectra, okubonisa ukuthi amangqamuzana e-microalgae amunca kuphela uhlobo lwe-oxide lwe-Nb.Ngaphezu kwalokho, silinganisele i-spectrum ye-C 1 nezici ze-C–C, CHx/C–O, C=O, kanye -COOH.Sabele iziqongo ze-CHx/C–O ne-C=O ekunikeleni ngemvelo kwamaseli ama-microalgae.Lezi zingxenye ze-organic zenza u-36% kanye no-41% weziqongo ze-C 1s ku-Nb2CTx SL kanye ne-Nb4C3TX SL, ngokulandelana.Sibe sesifaka i-spectra ye-O 1s ye-SL Nb2CTx ne-SL Nb4C3TX ne-Nb2O5, izingxenye eziphilayo ze-microalgae (CHx/CO), namanzi adsorbed angaphezulu.
Ekugcineni, imiphumela ye-XPS ikhombise ngokusobala uhlobo lwe-Nb, hhayi nje ubukhona bayo.Ngokwesikhundla sesignali ye-Nb 3d kanye nemiphumela ye-deconvolution, siqinisekisa ukuthi i-Nb idonswa kuphela ngendlela yama-oxides hhayi ama-ion noma i-MXene ngokwayo.Ngaphezu kwalokho, imiphumela ye-XPS ibonise ukuthi amaseli e-microalgae anamandla amakhulu okuthatha ama-Nb oxides asuka ku-SL Nb2CTx uma kuqhathaniswa ne-SL Nb4C3TX MXene.
Nakuba imiphumela yethu yokuthatha i-Nb ihlaba umxhwele futhi isivumela ukuthi sihlonze ukucekelwa phansi kwe-MXene, ayikho indlela etholakalayo yokulandelela izinguquko ezihlotshaniswayo ze-morphological ku-2D nanoflakes.Ngakho-ke, siphinde sanquma ukuthuthukisa indlela efanelekile engaphendula ngokuqondile kunoma yiziphi izinguquko ezenzeka ku-2D Nb-MXene nanoflakes namaseli ama-microalgae.Kubalulekile ukuqaphela ukuthi sithatha ngokuthi uma izinhlobo ezisebenzisanayo ziba nanoma ikuphi ukuguqulwa, ukubola noma ukuhlukaniswa, lokhu kufanele kubonakale ngokushesha njengezinguquko kumapharamitha womumo, njengobubanzi bendawo eyindilinga efanayo, ukuyindilinga, ububanzi beFeret, noma ubude beFeret.Njengoba le mingcele ifaneleka ukuchaza izinhlayiya ezinde noma ama-nanoflake anezinhlangothi ezimbili, ukulandelela kwawo ngokuhlaziywa komumo wezinhlayiyana eziguqukayo kuzosinika ulwazi olubalulekile mayelana nokuguqulwa kwe-morphological ye-SL Nb-MXene nanoflakes ngesikhathi sokunciphisa.
Imiphumela etholiwe iboniswa ku-Figure 6. Ukuze uqhathanise, siphinde sahlola isigaba sokuqala se-MAX kanye ne-ML-MXenes (bona i-SI Figures S18 ne-S19).Ukuhlaziywa okunamandla kokuma kwezinhlayiyana kubonise ukuthi wonke amapharamitha womumo we-Nb-MXene SLs amabili ashintshe kakhulu ngemva kokusebenzelana ne-microalgae.Njengoba kuboniswa ipharamitha yobubanzi bendawo eyindilinga elinganayo (Umfanekiso 6a, b), ukushuba okuphezulu okuncishisiwe kwengxenyana yama-nanoflake amakhulu kubonisa ukuthi avame ukubola abe yizingcezu ezincane.Emkhiwaneni.I-6c, d ibonisa ukwehla kweziqongo ezihlotshaniswa nosayizi oguquguqukayo wama-flakes (ukwelulwa kwama-nanoflakes), okubonisa ukuguqulwa kwama-nanoflakes angu-2D abe umumo ofana nezinhlayiyana.Umfanekiso 6e-h obonisa ububanzi nobude beFeret, ngokulandelana.Ububanzi nobude be-Feret kuyimingcele ehambisanayo ngakho-ke kufanele kubhekwe ndawonye.Ngemuva kokufakwa kwe-2D Nb-MXene nanoflakes ebukhoneni be-microalgae, iziqongo zabo zokuxhumanisa i-Feret zashintsha futhi ukuqina kwazo kwehla.Ngokusekelwe kule miphumela kuhlanganiswe ne-morphology, i-XRF ne-XPS, siphethe ngokuthi izinguquko eziphawuliwe zihlobene kakhulu ne-oxidation njengoba ama-MXenes ane-oxidized eba nemibimbi futhi ahlehle abe yizicucu kanye nezinhlayiya ze-oxide eyindilinga69,70.
Ukuhlaziywa kokuguqulwa kwe-MXene ngemva kokusebenzelana ne-microalgae eluhlaza.Ukuhlaziywa komumo wezinhlayiyana ezinamandla kucabangela amapharamitha afana (a, b) nobubanzi bendawo eyindilinga efanayo, (c, d) ukuyindilinga, (e, f) ububanzi be-Feret kanye (g, h) nobude be-Feret.Kuze kube manje, amasampula e-microalgae ayireferensi amabili ahlaziywa kanye ne-SL Nb2CTx eyinhloko kanye ne-SL Nb4C3Tx MXenes, SL Nb2CTx kanye ne-SL Nb4C3Tx MXenes, ama-microalgae eyonakele, kanye ne-microalgae SL Nb2CTx ephathwayo kanye ne-SL Nb4C3Tx MX.Imicibisholo ebomvu ibonisa ukushintshwa kwamapharamitha womumo wama-nanoflake anezinhlangothi ezimbili ezifundwayo.
Njengoba ukuhlaziywa kwepharamitha yomumo kuthembeke kakhulu, kungase futhi kwembule izinguquko ze-morphological kumaseli ama-microalgae.Ngakho-ke, sihlaziye ububanzi obulinganayo bendawo eyindilinga, ubuyindilinga, nobubanzi/ubude be-Feret bamaseli namaseli e-microalgae ahlanzekile ngemva kokusebenzelana nama-nanoflakes angu-2D Nb.Emkhiwaneni.I-6a–h ibonisa izinguquko kumapharamitha womumo wamangqamuzana olwelwe, njengoba kufakazelwa ukuncipha kokuqina okukhulu kanye noshintsho lwe-maxima ukuya kumanani aphezulu.Ikakhulukazi, imingcele ye-cell roundness ibonise ukwehla kwamaseli amade kanye nokwanda kwamaseli ayindilinga (Fig. 6a, b).Ukwengeza, ububanzi beseli ye-Feret bukhuphuke ngama-micrometer amaningana ngemva kokuxhumana ne-SL Nb2CTx MXene (Fig. 6e) uma kuqhathaniswa ne-SL Nb4C3TX MXene (Fig. 6f).Sisola ukuthi lokhu kungenzeka kungenxa yokuthatha okuqinile kwe-Nb oxides nge-microalgae lapho kusebenzisana ne-Nb2CTx SR.Ukunamathiselwa okuqinile okuncane kwama-Nb flakes ebusweni bawo kungaholela ekukhuleni kweseli ngomphumela omncane wokuthungatha.
Ukuqaphela kwethu izinguquko kumapharamitha womumo nosayizi we-microalgae kuhambisana nezinye izifundo.Ama-microalgae aluhlaza angashintsha i-morphology yawo ekuphenduleni ukucindezeleka kwendawo ngokushintsha usayizi weseli, ukwakheka noma i-metabolism61.Isibonelo, ukushintsha usayizi wamaseli kusiza ukumuncwa kwezakhamzimba71.Amangqamuzana amancane e-algae abonisa ukutholakala kwezakhi eziphansi kanye nezinga lokukhula eliphazamisekile.Ngokuphambene, amangqamuzana amakhulu athambekele ekudleni imisoco ethe xaxa, abese efakwa ngaphakathi kwe-intracellularly72,73.UMachado no-Soares bathola ukuthi i-triclosan yokukhunta ingakhuphula usayizi weseli.Baphinde bathola izinguquko ezijulile ekubunjweni kwe-algae74.Ngaphezu kwalokho, u-Yin et al.9 uphinde wembula izinguquko ze-morphological ku-algae ngemva kokuchayeka ekunciphiseni ama-graphene oxide nanocomposites.Ngakho-ke, kusobala ukuthi usayizi oshintshiwe / imingcele yesimo se-microalgae ibangelwa ukuba khona kwe-MXene.Njengoba lolu shintsho ngosayizi nokuma lubonisa izinguquko ekuthathweni kwezakhi, sikholelwa ukuthi ukuhlaziywa kosayizi namapharamitha womumo ngokuhamba kwesikhathi kungabonisa ukutholwa kwe-niobium oxide nge-microalgae phambi kwe-Nb-MXenes.
Ngaphezu kwalokho, i-MXenes ingafakwa i-oxidized phambi kwe-algae.U-Dalai et al.75 waqaphela ukuthi i-morphology ye-algae eluhlaza evezwe ku-nano-TiO2 ne-Al2O376 yayingeyona iyunifomu.Nakuba ukuqaphela kwethu kufana nocwaningo lwamanje, lufanelekile kuphela ekutadisheni imiphumela ye-bioremediation ngokwemikhiqizo ye-MXene yokuwohloka phambi kwama-nanoflakes we-2D hhayi ama-nanoparticles.Njengoba ama-MXenes angakwazi ukuwohloka abe yi-metal oxides, i-31,32,77,78 kunengqondo ukucabanga ukuthi ama-nanoflakes ethu e-Nb angakwazi futhi ukwakha ama-Nb oxides ngemva kokuxhumana namaseli ama-microalgae.
Ukuze sichaze ukuncishiswa kwama-nanoflakes we-2D-Nb ngokusebenzisa indlela yokubola ngokusekelwe kunqubo ye-oxidation, senze izifundo zisebenzisa i-high-resolution transmission electron microscopy (HRTEM) (Fig. 7a,b) kanye ne-X-ray photoelectron spectroscopy (XPS) (Fig. 7).7c-i namathebula S4-5).Zombili izindlela zilungele ukutadisha i-oxidation yezinto ze-2D futhi ziyaphelelisana.I-HRTEM iyakwazi ukuhlaziya ukuwohloka kwezakhiwo ezinezingqimba ezinezinhlangothi ezimbili kanye nokuvela okulandelayo kwe-metal oxide nanoparticles, kuyilapho i-XPS izwela kumabhondi angaphezulu.Ngale njongo, sihlole ama-nanoflakes e-2D Nb-MXene akhishwe kuma-microalgae cell dispersions, okungukuthi, ukuma kwawo ngemva kokuxhumana namaseli ama-microalgae (bheka u-Fig. 7).
Izithombe ze-HRTEM ezibonisa i-morphology ye-oxidized (a) SL Nb2CTx kanye (b) SL Nb4C3Tx MXenes, imiphumela yokuhlaziya ye-XPS ebonisa (c) ukwakheka kwemikhiqizo ye-oxide ngemva kokunciphisa, (d–f) ukufanisa okuphezulu kwezingxenye ze-XPS spectra ye-SL Nb2CTx kanye (g– iT) ne-Nb4C ehlaza yokulungisa i-Nb4C ye-Nb4C.
Ucwaningo lwe-HRTEM luqinisekisile i-oxidation yezinhlobo ezimbili ze-Nb-MXene nanoflakes.Nakuba ama-nanoflakes agcina i-morphology yawo enezinhlangothi ezimbili ngezinga elithile, i-oxidation ibangele ukubonakala kwama-nanoparticles amaningi amboza ubuso be-MXene nanoflakes (bheka umdwebo 7a, b).Ukuhlaziywa kwe-XPS kwezimpawu ze-c Nb 3d kanye ne-O 1s kubonise ukuthi ama-Nb oxides akhiwe kuzo zombili izimo.Njengoba kuboniswe kuMfanekiso 7c, i-2D MXene Nb2CTx ne-Nb4C3TX inezimpawu ze-Nb 3d ezibonisa ukuba khona kwe-NbO kanye ne-Nb2O5 oxides, kuyilapho amasiginali we-O 1s abonisa inani lamabhondi e-O-Nb ahlotshaniswa nokusebenza kwendawo ye-2D nanoflake.Siqaphele ukuthi umnikelo we-Nb oxide ukhonya uma kuqhathaniswa ne-Nb-C ne-Nb3+-O.
Emkhiwaneni.Izibalo 7g–i zibonisa i-XPS spectra ye-Nb 3d, C 1s, ne-O 1s SL Nb2CTx (bona ama-Figs. 7d–f) kanye ne-SL Nb4C3TX MXene ehlukanisiwe kumaseli ama-microalgae.Imininingwane yamapharamitha aphakeme we-Nb-MXenes inikezwa kumaThebula S4–5, ngokulandelana.Siqale sahlaziya ukwakheka kwe-Nb 3d.Ngokuphambene ne-Nb emuncwe amangqamuzana e-microalgae, ku-MXene ehlukanisiwe namaseli e-microalgae, ngaphandle kwe-Nb2O5, ezinye izingxenye zatholakala.Ku-Nb2CTx SL, sibone umnikelo we-Nb3+-O ngenani elingu-15%, kuyilapho yonke i-spectrum ye-Nb 3d ibuswe yi-Nb2O5 (85%).Ngaphezu kwalokho, isampula ye-SL Nb4C3TX iqukethe izingxenye ze-Nb-C (9%) kanye ne-Nb2O5 (91%).Lapha i-Nb-C ivela ezingxenyeni ezimbili ze-athomu zangaphakathi ze-metal carbide ku-Nb4C3Tx SR.Sibe sesibeka imephu ye-spectra ye-C 1s ezingxenyeni ezine ezahlukene, njengoba senzile kumasampuli afakwe ngaphakathi.Njengoba kulindelekile, i-spectrum ye-C 1s ibuswa i-graphic carbon, ilandelwa yiminikelo evela ezinhlayiyeni eziphilayo (CHx/CO kanye ne-C=O) ezivela kumaseli ama-microalgae.Ngaphezu kwalokho, ku-spectrum ye-O 1s, sibone umnikelo wezinhlobo eziphilayo zamaseli ama-microalgae, i-niobium oxide, namanzi adsorbed.
Ukwengeza, siphenye ukuthi i-Nb-MXenes cleavage ihlotshaniswa nokuba khona kwezinhlobo ze-oxygen esebenzayo (ROS) endaweni yezakhi kanye/noma amangqamuzana e-microalgae.Kuze kube manje, sihlole amazinga e-singlett oxygen (1O2) endaweni yesiko kanye ne-intracellular glutathione, i-thiol esebenza njenge-antioxidant ku-microalgae.Imiphumela ikhonjiswa ku-SI (Figures S20 and S21).Amasiko ane-SL Nb2CTx kanye ne-Nb4C3TX MXenes aye abonakala ngenani elincishisiwe le-1O2 (bona Umfanekiso S20).Endabeni ye-SL Nb2CTx, i-MXene 1O2 yehliswa yaba cishe ku-83%.Kumasiko ama-microalgae asebenzisa i-SL, i-Nb4C3TX 1O2 yehle nakakhulu, yaya ku-73%.Kuyathakazelisa ukuthi izinguquko ku-1O2 zibonise ukuthambekela okufanayo njengomphumela wokuvimbela-okuvuselelayo owabonwa ngaphambilini (bheka u-Fig. 3).Kungaphikiswana ngokuthi ukufukamela ekukhanyeni okukhanyayo kungashintsha i-photooxidation.Kodwa-ke, imiphumela yokuhlaziywa kokulawula ibonise amazinga acishe abe njalo we-1O2 ngesikhathi sokuhlolwa (Fig. S22).Endabeni yamazinga e-ROS e-intracellular, siphinde sabona ukuthambekela okufanayo kokwehla (bona Umfanekiso S21).Ekuqaleni, amazinga e-ROS kumaseli e-microalgae akhuliswe phambi kwe-Nb2CTx ne-Nb4C3Tx SLs ayedlula amazinga atholakala kumasiko ahlanzekile we-microalgae.Nokho, ekugcineni kwabonakala sengathi i-microalgae ivumelanisa nokuba khona kokubili kwe-Nb-MXenes, njengoba amazinga e-ROS ehla ku-85% kanye ne-91% yamazinga alinganiswa kumasiko ahlanzekile we-microalgae efakwe nge-SL Nb2CTx ne-Nb4C3TX, ngokulandelana.Lokhu kungase kubonise ukuthi ama-microalgae azizwa ekhululekile ngokuhamba kwesikhathi ebukhoneni be-Nb-MXene kunasendaweni yezakhi zodwa.
Ama-Microalgae ayiqembu elihlukahlukene lezinto eziphilayo ze-photosynthetic.Ngesikhathi se-photosynthesis, baguqula i-carbon dioxide yasemkhathini (CO2) ibe yi-organic carbon.Imikhiqizo ye-photosynthesis yi-glucose ne-oxygen79.Sisola ukuthi i-oksijeni eyakhiwe ngaleyo ndlela idlala indima ebalulekile ku-oxidation ye-Nb-MXenes.Enye incazelo engenzeka yalokhu ukuthi ipharamitha yokuhlukanisa i-aeration yakhiwe ngezingcindezi eziphansi neziphezulu ze-oksijini ngaphandle nangaphakathi kwe-Nb-MXene nanoflakes.Lokhu kusho ukuthi noma kuphi lapho kunezindawo zokucindezela okuyingxenye okuhlukene kwe-oksijeni, indawo enezinga eliphansi kakhulu izokwakha i-anode 80, 81, 82. Lapha, i-microalgae ifaka isandla ekudalweni kwamangqamuzana ahlukene aerated ebusweni be-MXene flakes, ekhiqiza umoya-mpilo ngenxa yezakhiwo zabo ze-photosynthetic.Ngenxa yalokho, imikhiqizo ye-biocorrosion (kulokhu, i-niobium oxides) yenziwa.Esinye isici ukuthi i-microalgae ingakhiqiza i-organic acids ekhishwa emanzini83,84.Ngakho-ke, kwakhiwa indawo enolaka, ngaleyo ndlela ishintsha ama-Nb-MXenes.Ngaphezu kwalokho, i-microalgae ingashintsha i-pH yendawo ibe yi-alkaline ngenxa yokumuncwa kwe-carbon dioxide, engase futhi ibangele ukugqwala79.
Okubaluleke nakakhulu, isikhathi sesithombe esimnyama/esikhanyayo esisetshenziswe ocwaningweni lwethu sibalulekile ekuqondeni imiphumela etholiwe.Lesi sici sichazwe ngokuningiliziwe ku-Djemai-Zoghlache et al.85 Basebenzise ngamabomu i-photoperiod yamahora angu-12/12 ukuze babonise i-biocorrosion ehlotshaniswa ne-biofouling yi-red microalgae i-Porphyridium purpureum.Zibonisa ukuthi i-photoperiod ihlotshaniswa nokuvela kwamandla ngaphandle kwe-biocorrosion, izibonakalisa njenge-pseudoperiodic oscillations cishe ngo-24:00.Lokhu kuqashelwa kwaqinisekiswa nguDowling et al.86 Babonisa ama-photosynthetic biofilms e-cyanobacteria Anabaena.I-oxygen encibilikisiwe yenziwa ngaphansi kwesenzo sokukhanya, esihlotshaniswa noshintsho noma ukushintshashintsha kwamandla amahhala e-biocorrosion.Ukubaluleka kwe-photoperiod kugcizelelwa yiqiniso lokuthi amandla amahhala e-biocorrosion ayanda esigabeni sokukhanya futhi ehle esigabeni esimnyama.Lokhu kubangelwa umoya-mpilo okhiqizwa i-photosynthetic microalgae, ethonya ukusabela kwe-cathodic ngokusebenzisa ukucindezela okuyingxenye okukhiqizwa eduze kwama-electrodes87.
Ukwengeza, i-Fourier transform infrared spectroscopy (FTIR) yenziwa ukuze kutholwe ukuthi ingabe kukhona ushintsho olwenzekile ekwakhekeni kwamakhemikhali amaseli ama-microalgae ngemva kokusebenzelana ne-Nb-MXenes.Le miphumela etholiwe iyinkimbinkimbi futhi siyethula ku-SI (Figures S23-S25, kuhlanganise nemiphumela yesiteji esingu-MAX kanye ne-ML MXenes).Kafushane, i-spectra yereferensi etholiwe ye-microalgae isinikeza ulwazi olubalulekile mayelana nezici zamakhemikhali zalezi zidalwa.Lokhu kudlidliza okungenzeka kakhulu kutholakala kumafrikhwensi angu-1060 cm-1 (CO), 1540 cm-1, 1640 cm-1 (C=C), 1730 cm-1 (C=O), 2850 cm-1, 2920 cm-1.eyodwa.1 1 (C–H) kanye no-3280 cm–1 (O–H).Ku-SL Nb-MXenes, sithole isiginesha yokwelula ibhondi engu-CH ehambisana nesifundo sethu sangaphambilini38.Kodwa-ke, siqaphele ukuthi ezinye iziqongo ezengeziwe ezihlotshaniswa namabhondi e-C=C kanye ne-CH anyamalele.Lokhu kubonisa ukuthi ukwakheka kwamakhemikhali we-microalgae kungase kube nezinguquko ezincane ngenxa yokusebenzisana ne-SL Nb-MXenes.
Uma kucutshungulwa izinguquko ezingaba khona ku-biochemistry ye-microalgae, ukunqwabelana kwama-inorganic oxides, njenge-niobium oxide, kudinga ukucatshangelwa kabusha59.Ihilelekile ekuthathweni kwezinsimbi nge-cell surface, ukuthuthwa kwazo ku-cytoplasm, ukuhlangana kwazo namaqembu e-intracellular carboxyl, kanye nokuqoqwa kwazo ku-microalgae polyphosphosomes20,88,89,90.Ngaphezu kwalokho, ubudlelwano phakathi kwama-microalgae nezinsimbi kugcinwa amaqembu asebenzayo amaseli.Ngalesi sizathu, ukumuncwa kuncike futhi kumakhemikhali angaphezulu kwe-microalgae, eyinkimbinkimbi9,91.Ngokuvamile, njengoba kulindelekile, ukwakheka kwamakhemikhali e-microalgae eluhlaza kwashintsha kancane ngenxa yokumuncwa kwe-Nb oxide.
Kuyathakazelisa ukuthi ukuvinjelwa kokuqala kwe-microalgae kwabuyiselwa emuva ngokuhamba kwesikhathi.Njengoba sibonile, i-microalgae yanqoba ukuguquka kwemvelo kokuqala futhi ekugcineni yabuyela emazingeni okukhula avamile futhi yanda.Ucwaningo lwamandla e-zeta lubonisa ukuzinza okuphezulu lapho kwethulwa kumidiya yezakhi.Ngakho-ke, ukusebenzisana kwendawo phakathi kwamaseli e-microalgae nama-Nb-MXene nanoflakes kwagcinwa kulo lonke ucwaningo lokunciphisa.Ekuhlaziyeni kwethu okuqhubekayo, sifingqa izindlela eziyinhloko zokwenza lokhu kuziphatha okumangalisayo kwe-microalgae.
Ukubuka kwe-SEM kubonise ukuthi i-microalgae ivame ukunamathela ku-Nb-MXenes.Ngokusebenzisa ukuhlaziywa kwesithombe esiguquguqukayo, siqinisekisa ukuthi lo mphumela uholela ekuguqulweni kwama-nanoflakes e-Nb-MXene enezinhlangothi ezimbili zibe yizinhlayiya eziyindilinga, ngaleyo ndlela kubonisa ukuthi ukubola kwama-nanoflakes kuhlotshaniswa ne-oxidation yabo.Ukuhlola i-hypothesis yethu, senze uchungechunge lwezifundo ezibonakalayo kanye ne-biochemical.Ngemva kokuhlolwa, ama-nanoflakes kancane kancane afakwa i-oxid futhi abola abe yimikhiqizo ye-NbO ne-Nb2O5, engazange ibe usongo ku-microalgae eluhlaza.Ngokusebenzisa ukubhekwa kwe-FTIR, asitholanga izinguquko ezibalulekile ekubunjweni kwamakhemikhali ama-microalgae afakwe phambi kwe-2D Nb-MXene nanoflakes.Ngokucabangela ukuthi kungenzeka yini ukumuncwa kwe-niobium oxide nge-microalgae, senze ukuhlaziya kwe-X-ray fluorescence.Le miphumela ikhombisa ngokusobala ukuthi i-microalgae efundisiwe idla i-niobium oxides (NbO ne-Nb2O5), engenabo ubuthi kuma-microalgae afundwayo.