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Saurin ci gaban fasahar nano da haɗakarta cikin aikace-aikacen yau da kullun na iya barazana ga muhalli. Duk da cewa hanyoyin kore don lalata gurɓatattun abubuwa na halitta an tabbatar da su sosai, dawo da gurɓatattun abubuwa marasa tsari yana da matukar damuwa saboda ƙarancin sauƙin fahimtar su ga canjin halittu da rashin fahimtar hulɗar saman abu da na halittu. A nan, muna amfani da samfurin 2D MXenes na inorganic wanda aka haɗa tare da hanyar nazarin sigogi mai sauƙi don bin diddigin tsarin bioremediation na nanomaterials na yumbu 2D ta hanyar ƙananan algae Raphidocelis subcapitata. Mun gano cewa ƙananan algae suna lalata MXenes na tushen Nb saboda hulɗar fisiko-sinadarai da ta shafi saman. Da farko, an haɗa nanoflakes na MXene mai layi ɗaya da mai layi da yawa zuwa saman microalgae, wanda ya ɗan rage girman algae. Duk da haka, bayan dogon hulɗa da saman, ƙananan algae sun yi oxidized nanoflakes na MXene kuma sun ƙara rusa su zuwa NbO da Nb2O5. Saboda waɗannan oxides ba su da guba ga ƙwayoyin microalgae, suna cinye ƙwayoyin Nb oxide ta hanyar hanyar sha wanda ke ƙara dawo da ƙwayoyin microalgae bayan awanni 72 na maganin ruwa. Tasirin abubuwan gina jiki da ke da alaƙa da sha kuma ana nuna su a cikin ƙaruwar yawan ƙwayoyin halitta, siffarsu mai santsi da canjin ƙimar girma. Dangane da waɗannan binciken, mun kammala da cewa kasancewar MXenes masu tushen Nb na ɗan gajeren lokaci da na dogon lokaci a cikin yanayin halittu masu ruwa-ruwa na iya haifar da ƙananan tasirin muhalli kawai. Abin lura ne cewa, ta amfani da kayan nano masu girma biyu a matsayin tsarin samfuri, muna nuna yiwuwar bin diddigin canjin siffa ko da a cikin kayan da aka yi da kyau. Gabaɗaya, wannan binciken yana amsa wata muhimmiyar tambaya game da hanyoyin da suka shafi hulɗar saman da ke haifar da tsarin bioremediation na kayan nano na 2D kuma yana ba da tushe don ƙarin nazarin ɗan gajeren lokaci da na dogon lokaci game da tasirin muhalli na kayan nano nano marasa tsari.
Kayan Nano sun haifar da sha'awa sosai tun lokacin da aka gano su, kuma fasahar nano daban-daban kwanan nan sun shiga matakin zamani1. Abin takaici, haɗa kayan nano a cikin aikace-aikacen yau da kullun na iya haifar da sakin bazata saboda zubar da su ba daidai ba, kulawa da rashin kulawa, ko rashin isasshen kayan aikin tsaro. Saboda haka, yana da kyau a ɗauka cewa kayan nano, gami da kayan nano masu girma biyu (2D), za a iya sakin su cikin yanayin halitta, waɗanda har yanzu ba a fahimci halayensu da ayyukan halittu ba. Saboda haka, ba abin mamaki ba ne cewa damuwar gubar muhalli ta mayar da hankali kan ikon kayan nano na 2D na shiga cikin tsarin ruwa2,3,4,5,6. A cikin waɗannan yanayin halittu, wasu kayan nano na 2D na iya hulɗa da halittu daban-daban a matakan trophic daban-daban, gami da ƙananan algae.
Ƙananan algae halittu ne na asali da ake samu a yanayi na halitta a cikin ruwan sha da muhalli na ruwa waɗanda ke samar da nau'ikan samfuran sinadarai ta hanyar photosynthesis7. Saboda haka, suna da mahimmanci ga yanayin halittu na ruwa8,9,10,11,12 amma kuma suna da alamun cutarwa, marasa tsada kuma ana amfani da su sosai na muhalli13,14. Tunda ƙwayoyin ƙananan algae suna ƙaruwa da sauri kuma suna amsawa da sauri ga kasancewar mahaɗan daban-daban, suna da alƙawarin haɓaka hanyoyin da ba su da illa ga muhalli don magance ruwan da ya gurɓata da abubuwan halitta15,16.
Kwayoyin algae na iya cire ions marasa tsari daga ruwa ta hanyar biosorption da tarawa17,18. Wasu nau'ikan algae kamar Chlorella, Anabaena invar, Westiellopsis prolifica, Stigeoclonium tenue da Synechococcus sp. An gano cewa yana ɗauke da kuma ciyar da ions na ƙarfe masu guba kamar Fe2+, Cu2+, Zn2+ da Mn2+19. Wasu bincike sun nuna cewa ions na Cu2+, Cd2+, Ni2+, Zn2+ ko Pb2+ suna iyakance girman Scenedesmus ta hanyar canza yanayin ƙwayoyin halitta da lalata chloroplasts ɗinsu20,21.
Hanyoyin kore don rugujewar gurɓatattun abubuwa na halitta da kuma kawar da ions na ƙarfe masu nauyi sun jawo hankalin masana kimiyya da injiniyoyi a duk faɗin duniya. Wannan ya faru ne saboda gaskiyar cewa waɗannan gurɓatattun abubuwa ana sarrafa su cikin sauƙi a matakin ruwa. Duk da haka, gurɓatattun abubuwa marasa tsari suna da alaƙa da ƙarancin narkewar ruwa da ƙarancin sauƙin kamuwa da canje-canje daban-daban na halittu, wanda ke haifar da matsaloli masu yawa a gyara, kuma ba a sami ci gaba sosai a wannan yanki ba22,23,24,25,26. Don haka, neman mafita masu kyau ga muhalli don gyara nanomaterials ya kasance yanki mai rikitarwa kuma ba a bincika ba. Saboda babban rashin tabbas game da tasirin biotransformation na nanomaterials na 2D, babu wata hanya mai sauƙi don gano hanyoyin da za su iya lalata su yayin raguwa.
A cikin wannan binciken, mun yi amfani da ƙananan ƙwayoyin halitta masu launin kore a matsayin wakili mai aiki a cikin ruwa don kayan yumbu marasa tsari, tare da sa ido a cikin yanayin aikin lalata MXene a matsayin wakilin kayan yumbu marasa tsari. Kalmar "MXene" tana nuna stoichiometry na kayan Mn+1XnTx, inda M ƙarfe ne na farko na canzawa, X shine carbon da/ko nitrogen, Tx shine mai ƙarewa a saman (misali, -OH, -F, -Cl), da n = 1, 2, 3 ko 427.28. Tun lokacin da Naguib et al. Sensorics, maganin ciwon daji da tace membrane 27,29,30 suka gano MXenes. Bugu da ƙari, ana iya ɗaukar MXenes a matsayin tsarin samfurin 2D saboda kyakkyawan kwanciyar hankali na colloidal da yiwuwar hulɗar halittu31,32,33,34,35,36.
Saboda haka, an nuna hanyar da aka ƙirƙira a cikin wannan labarin da kuma hasashen bincikenmu a Hoto na 1. Dangane da wannan hasashe, ƙananan algae suna lalata MXenes masu tushen Nb zuwa mahaɗan da ba su da guba saboda hulɗar da ke da alaƙa da yanayin jiki da sinadarai, wanda ke ba da damar sake farfaɗo da algae. Don gwada wannan hasashe, an zaɓi mambobi biyu na dangin farkon carbides na ƙarfe mai canzawa na niobium da/ko nitrides (MXenes), wato Nb2CTx da Nb4C3TX.
Hanyar bincike da hasashe bisa ga shaida don murmurewa daga ƙwayoyin halittar MXene ta hanyar ƙwayoyin halittar kore Raphidocelis subcapitata. Lura cewa wannan kawai wakilci ne na zato bisa ga shaida. Yanayin tafkin ya bambanta a cikin yanayin abinci mai gina jiki da ake amfani da shi da kuma yanayin (misali, zagayowar rana da ƙuntatawa a cikin muhimman abubuwan gina jiki da ake da su). An ƙirƙira shi da BioRender.com.
Saboda haka, ta hanyar amfani da MXene a matsayin tsarin samfuri, mun buɗe ƙofa don nazarin tasirin halittu daban-daban waɗanda ba za a iya gani tare da sauran kayan nano na gargajiya ba. Musamman, mun nuna yiwuwar gyara yanayin nanomaterials masu girma biyu, kamar MXenes masu tushen niobium, ta hanyar microalgae Raphidocelis subcapitata. Microalgae suna iya lalata Nb-MXenes zuwa oxides marasa guba NbO da Nb2O5, waɗanda kuma ke samar da abubuwan gina jiki ta hanyar tsarin ɗaukar niobium. Gabaɗaya, wannan binciken yana amsa wata muhimmiyar tambaya game da hanyoyin da ke da alaƙa da hulɗar sinadaran saman da ke jagorantar hanyoyin magance bioremediation na kayan nano masu girma biyu. Bugu da ƙari, muna haɓaka wata hanya mai sauƙi ta tushen siffa don bin diddigin canje-canje a cikin siffar kayan nano na 2D. Wannan yana ƙarfafa ƙarin bincike na ɗan gajeren lokaci da na dogon lokaci game da tasirin muhalli daban-daban na kayan nano na inorganic crystalline. Don haka, bincikenmu yana ƙara fahimtar hulɗar tsakanin saman kayan da kayan halitta. Muna kuma samar da tushe don fadada nazarin na ɗan gajeren lokaci da na dogon lokaci game da tasirinsu ga yanayin halittu masu ruwa da tsaki, wanda yanzu za a iya tabbatar da shi cikin sauƙi.
MXenes suna wakiltar aji mai ban sha'awa na kayan aiki tare da halaye na zahiri da sinadarai na musamman da kuma masu jan hankali, don haka akwai aikace-aikace da yawa da za a iya amfani da su. Waɗannan halaye sun dogara ne da stoichiometry da kuma sinadaran saman su. Saboda haka, a cikin bincikenmu, mun bincika nau'ikan MXenes guda biyu na Nb-based hierarchical one-layer (SL), Nb2CTx da Nb4C3TX, tunda ana iya ganin tasirin halittu daban-daban na waɗannan kayan nano. Ana samar da MXenes daga kayan farawarsu ta hanyar zaɓaɓɓen zaɓaɓɓun yadudduka na MAX-phase A-laye masu sirara. Matakin MAX wani yumbu ne mai ternary wanda ya ƙunshi tubalan "haɗe" na carbide na ƙarfe mai canzawa da siraran abubuwa na "A" kamar Al, Si, da Sn tare da stoichiometry na MnAXn-1. An lura da yanayin farkon matakin MAX ta hanyar duba na'urar microscopy ta lantarki (SEM) kuma ya yi daidai da binciken da ya gabata (Duba Ƙarin Bayani, SI, Hoto na S1). An sami Nb-MXene mai layi ɗaya (ML) bayan cire layin Al tare da 48% HF (hydrofluoric acid). An duba yanayin ML-Nb2CTx da ML-Nb4C3TX ta hanyar duba na'urar daukar hoton lantarki (SEM) (Figures S1c da S1d bi da bi) kuma an lura da yanayin MXene mai layi-layi, kama da nanoflakes masu girma biyu da ke ratsawa ta cikin ramuka masu tsayi kamar ramuka. Dukansu Nb-MXenes suna da abubuwa da yawa iri ɗaya da matakan MXene da aka haɗa ta hanyar etching acid27,38. Bayan tabbatar da tsarin MXene, mun haɗa shi ta hanyar haɗa tetrabutylammonium hydroxide (TBAOH) sannan muka wanke da sonication, bayan haka muka sami nanoflakes mai layi ɗaya ko ƙasa (SL) 2D Nb-MXene.
Mun yi amfani da na'urar hangen nesa ta lantarki mai ƙuduri mai girma (HRTEM) da kuma na'urar hangen nesa ta X-ray (XRD) don gwada ingancin etching da kuma ƙarin barewa. An nuna sakamakon HRTEM da aka sarrafa ta amfani da Inverse Fast Fourier Transform (IFFT) da Fast Fourier Transform (FFT) a cikin Hoto na 2. An mayar da hankali kan nanoflakes na Nb-MXene zuwa gefen sama don duba tsarin Layer na atomic da kuma auna nisan da ke tsakanin planar. Hotunan HRTEM na nanoflakes na MXene Nb2CTx da Nb4C3TX sun bayyana yanayin su mai sirara a atomic (duba Hoto na 2a1, a2), kamar yadda Naguib et al.27 da Jastrzębska et al.38 suka ruwaito a baya. Ga guda biyu masu layi ɗaya na Nb2CTx da Nb4C3Tx, mun ƙayyade nisan da ke tsakanin layukan 0.74 da 1.54 nm, bi da bi (Hoto na 2b1,b2), wanda kuma ya yi daidai da sakamakonmu na baya38. An ƙara tabbatar da wannan ta hanyar juyi mai sauri na Fourier (Hoto na 2c1, c2) da kuma saurin juyin Fourier (Hoto na 2d1, d2) wanda ke nuna nisan da ke tsakanin layukan Nb2CTx da Nb4C3Tx. Hoton yana nuna canjin madauri na haske da duhu wanda ya dace da ƙwayoyin niobium da carbon, wanda ke tabbatar da yanayin da aka yi nazari a kai na MXenes. Yana da mahimmanci a lura cewa spectra mai watsa makamashi na X-ray spectroscopy (EDX) da aka samu don Nb2CTx da Nb4C3Tx (Hoto na S2a da S2b) bai nuna ragowar matakin MAX na asali ba, tunda ba a gano kololuwar Al ba.
Halayen nanoflakes na SL Nb2CTx da Nb4C3Tx MXene, gami da (a) hoton nanoflake na 2D na gefe mai ƙuduri mai girma (HRTEM) da kuma dacewa, (b) yanayin ƙarfi, (c) juyewar sauri Fourier transform (IFFT), (d) saurin Fourier transform (FFT), (e) Tsarin X-ray na Nb-MXenes. Ga SL 2D Nb2CTx, ana bayyana lambobin kamar haka (a1, b1, c1, d1, e1). Ga SL 2D Nb4C3Tx, ana bayyana lambobin kamar haka (a2, b2, c2, d2, e1).
An nuna ma'aunin watsa hasken X-ray na SL Nb2CTx da Nb4C3Tx MXenes a cikin Fig. 2e1 da e2, bi da bi. Kololuwa (002) a 4.31 da 4.32 sun yi daidai da MXenes masu layi Nb2CTx da Nb4C3TX38,39,40,41 da aka bayyana a baya. Sakamakon XRD kuma yana nuna kasancewar wasu sifofi na ML da suka rage da kuma matakan MAX, amma galibin sifofin XRD da ke da alaƙa da SL Nb4C3Tx (Hoto na 2e2). Kasancewar ƙananan ƙwayoyin cuta na matakin MAX na iya bayyana ƙarfin kololuwar MAX idan aka kwatanta da layukan Nb4C3Tx da aka tara bazuwar.
Ƙarin bincike ya mayar da hankali kan ƙananan ƙwayoyin cuta na ƙwayoyin cuta na nau'in R. subcapitata. Mun zaɓi ƙananan ƙwayoyin cuta saboda su ne masu samar da sinadarai masu mahimmanci da ke da hannu a cikin manyan hanyoyin samar da abinci42. Hakanan suna ɗaya daga cikin mafi kyawun alamun guba saboda ikon cire abubuwa masu guba waɗanda ake ɗauka zuwa manyan matakan sarkar abinci43. Bugu da ƙari, bincike kan R. subcapitata na iya haskaka gubar SL Nb-MXenes ga ƙananan ƙwayoyin cuta na ruwa. Don misalta wannan, masu binciken sun yi hasashen cewa kowace ƙwayar cuta tana da bambancin ji na sinadarai masu guba da ke cikin muhalli. Ga yawancin halittu, ƙarancin yawan abubuwa ba ya shafar girmansu, yayin da yawan da ke sama da wani iyaka na iya hana su ko ma haifar da mutuwa. Saboda haka, don nazarinmu game da hulɗar saman tsakanin ƙananan ƙwayoyin cuta da MXenes da murmurewa da ke da alaƙa, mun yanke shawarar gwada yawan Nb-MXenes marasa lahani da guba. Domin yin wannan, mun gwada yawan 0 (a matsayin misali), 0.01, 0.1 da 10 mg na MXene l-1 da kuma ƙarin ƙwayoyin cuta masu kamuwa da cuta waɗanda ke da yawan MXene mai yawa (100 mg na L-1 MXene), wanda zai iya zama mai tsanani da kuma kisa ga kowace muhallin halittu.
An nuna tasirin SL Nb-MXenes akan ƙananan ƙwayoyin cuta a cikin Hoto na 3, wanda aka bayyana a matsayin kashi na haɓaka girma (+) ko hana (-) da aka auna don samfuran 0 mg l-1. Don kwatantawa, an kuma gwada matakin Nb-MAX da ML Nb-MXenes kuma an nuna sakamakon a cikin SI (duba Hoto na S3). Sakamakon da aka samu ya tabbatar da cewa SL Nb-MXenes kusan ba shi da guba a cikin kewayon ƙananan taro daga 0.01 zuwa 10 mg/l, kamar yadda aka nuna a Hoto na 3a, b. A cikin yanayin Nb2CTx, ba mu lura da gubar muhalli fiye da 5% a cikin kewayon da aka ƙayyade ba.
An yi nazarin yadda ƙwayoyin cuta ke ƙaruwa (+) ko hana (-) girma a cikin ƙwayoyin cuta idan aka samu SL (a) Nb2CTx da (b) Nb4C3TX MXene. An yi nazarin hulɗar MXene da ƙwayoyin cuta na tsawon awanni 24, 48 da 72. An yi wa muhimman bayanai (gwajin t, p < 0.05) alama da alamar tauraro (*). An yi wa muhimman bayanai (gwajin t, p < 0.05) alama da alamar tauraro (*). Значимые данные (t-критерий, p <0,05) отмечены звездочкой (*). An yi wa muhimman bayanai (gwajin t, p < 0.05) alama da alamar tauraro (*).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-gwajin, p <0,05) отмечены звездочкой (*). Muhimman bayanai (gwajin t, p < 0.05) an yi musu alama da alamar tauraro (*).Kibiyoyi ja suna nuna kawar da motsin hanawa.
A gefe guda kuma, ƙarancin yawan Nb4C3TX ya zama ɗan guba kaɗan, amma bai fi 7% ba. Kamar yadda aka zata, mun lura cewa MXenes suna da guba mafi girma da hana haɓakar ƙananan algae a 100mg L-1. Abin sha'awa, babu ɗayan kayan da suka nuna irin wannan yanayin da dogaro da lokaci na tasirin guba/mai guba idan aka kwatanta da samfuran MAX ko ML (duba SI don ƙarin bayani). Yayin da ga matakin MAX (duba Hoto na S3) guba ta kai kusan 15-25% kuma ta ƙaru da lokaci, an lura da yanayin juyi ga SL Nb2CTx da Nb4C3TX MXene. Hana haɓakar ƙananan algae ya ragu akan lokaci. Ya kai kusan 17% bayan awanni 24 kuma ya faɗi ƙasa da 5% bayan awanni 72 (Hoto na 3a, b, bi da bi).
Mafi mahimmanci, ga SL Nb4C3TX, hana haɓakar ƙwayoyin cuta ta microalgae ya kai kusan kashi 27% bayan awanni 24, amma bayan awanni 72 ya ragu zuwa kusan kashi 1%. Saboda haka, mun sanya wa tasirin da aka lura alama a matsayin hana haɓakawar ƙwayoyin cuta ta juye, kuma tasirin ya fi ƙarfi ga SL Nb4C3TX MXene. An lura da ƙarfafa haɓakar ƙwayoyin cuta ta microalgae a baya tare da Nb4C3TX (hulɗa a 10 mg L-1 na tsawon awanni 24) idan aka kwatanta da SL Nb2CTx MXene. Hakanan an nuna tasirin juyawar hana haɓakawa da haɓakawa a cikin lanƙwasa na biomass sau biyu (duba Hoto na S4 don cikakkun bayanai). Zuwa yanzu, an yi nazarin gubar muhalli na Ti3C2TX MXene kawai ta hanyoyi daban-daban. Ba ya da guba ga embryos na zebrafish44 amma yana da ɗanɗanon muhalli ga ƙwayoyin cuta na Desmodesmus quadricauda da Sorghum saccharatum45. Sauran misalan takamaiman tasirin sun haɗa da mafi girman guba ga layukan ƙwayoyin cuta fiye da layukan ƙwayoyin halitta na yau da kullun46,47. Ana iya ɗauka cewa yanayin gwajin zai yi tasiri ga canje-canje a cikin girman ƙananan ƙwayoyin halitta da aka gani a gaban Nb-MXenes. Misali, pH na kimanin 8 a cikin stroma na chloroplast shine mafi kyau don ingantaccen aikin enzyme na RuBisCO. Saboda haka, canje-canjen pH suna shafar ƙimar photosynthesis48,49. Duk da haka, ba mu lura da manyan canje-canje a cikin pH ba yayin gwajin (duba SI, Hoto na S5 don cikakkun bayanai). Gabaɗaya, al'adun ƙananan ƙwayoyin halitta tare da Nb-MXenes sun ɗan rage pH na maganin akan lokaci. Duk da haka, wannan raguwar yayi kama da canjin pH na matsakaici mai tsabta. Bugu da ƙari, kewayon bambance-bambancen da aka samu yayi kama da wanda aka auna don ingantaccen al'adun ƙananan ƙwayoyin halitta (samfurin sarrafawa). Don haka, mun kammala da cewa canje-canje a cikin pH akan lokaci ba ya shafar photosynthesis.
Bugu da ƙari, MXenes da aka haɗa suna da ƙarshen saman (wanda aka nuna a matsayin Tx). Waɗannan galibi ƙungiyoyi ne masu aiki -O, -F da -OH. Duk da haka, sunadarai na saman yana da alaƙa kai tsaye da hanyar haɗa su. An san cewa waɗannan ƙungiyoyin suna rarrabawa bazuwar a saman, wanda hakan ke sa ya yi wuya a yi hasashen tasirinsu akan halayen MXene50. Ana iya jayayya cewa Tx na iya zama ƙarfin catalytic don oxidation na niobium ta hanyar haske. Ƙungiyoyin aikin saman hakika suna ba da wurare da yawa na toshewa ga masu ɗaukar hoto don samar da heterojunctions51. Duk da haka, matsakaicin haɓakar abun ciki bai samar da ingantaccen mai ɗaukar hoto ba (ana iya samun cikakken abun ciki na matsakaici a cikin Tebur SI S6). Bugu da ƙari, duk wani gyare-gyaren saman yana da matukar muhimmanci, saboda ana iya canza ayyukan halittu na MXenes saboda aikin bayan-sarrafawa, oxidation, gyaran saman sinadarai na mahaɗan halitta da marasa halitta52,53,54,55,56 ko injiniyan cajin saman38. Saboda haka, domin gwada ko niobium oxide yana da alaƙa da rashin daidaiton abu a cikin matsakaici, mun gudanar da bincike kan yuwuwar zeta (ζ) a cikin matsakaicin girma na ƙananan algae da kuma ruwan da aka cire (don kwatantawa). Sakamakonmu ya nuna cewa SL Nb-MXenes suna da daidaito sosai (duba Siffar SI S6 don sakamakon MAX da ML). Ƙarfin zeta na SL MXenes yana da kusan -10 mV. A yanayin SR Nb2CTx, ƙimar ζ ta ɗan fi ta Nb4C3Tx mara kyau. Irin wannan canji a cikin ƙimar ζ na iya nuna cewa saman nanoflakes na MXene mara kyau yana shan ions masu caji mai kyau daga matsakaicin al'ada. Ma'aunin lokaci na yuwuwar zeta da kuma watsar da Nb-MXenes a cikin matsakaicin al'ada (duba Sifofi S7 da S8 a cikin SI don ƙarin bayani) da alama suna tallafawa hasashenmu.
Duk da haka, duka Nb-MXene SLs sun nuna ƙananan canje-canje daga sifili. Wannan a bayyane yake yana nuna daidaiton su a cikin yanayin girma na ƙananan algae. Bugu da ƙari, mun tantance ko kasancewar ƙananan algae ɗinmu masu kore zai shafi daidaiton Nb-MXenes a cikin matsakaici. Sakamakon yuwuwar zeta da watsawar MXenes bayan hulɗa da ƙananan algae a cikin hanyoyin gina jiki da al'adu akan lokaci ana iya samun su a cikin SI (Figures S9 da S10). Abin sha'awa, mun lura cewa kasancewar ƙananan algae ya yi kama da ya daidaita watsawar MXenes guda biyu. A yanayin Nb2CTx SL, yuwuwar zeta ta ɗan ragu kaɗan akan lokaci zuwa ƙarin ƙima mara kyau (-15.8 akan -19.1 mV bayan awanni 72 na haɗuwa). Iyakar zeta na SL Nb4C3TX ya ɗan ƙaru kaɗan, amma bayan awanni 72 har yanzu ya nuna kwanciyar hankali mafi girma fiye da nanoflakes ba tare da kasancewar ƙananan algae ba (-18.1 vs. -9.1 mV).
Mun kuma gano cewa ƙarancin wutar lantarki na maganin Nb-MXene da aka saka a gaban ƙananan ƙwayoyin halitta, yana nuna ƙarancin adadin ions a cikin sinadarin gina jiki. Abin lura shi ne, rashin daidaiton MXenes a cikin ruwa ya samo asali ne daga iskar oxygen a saman ƙasa57. Saboda haka, muna zargin cewa ƙananan ƙwayoyin halitta na kore sun share oxides da aka samar a saman Nb-MXene har ma sun hana faruwarsu (haɗarin MXene). Ana iya ganin wannan ta hanyar nazarin nau'ikan abubuwan da ƙananan ƙwayoyin halitta ke sha.
Duk da cewa bincikenmu na muhalli ya nuna cewa ƙananan ƙwayoyin cuta sun sami damar shawo kan gubar Nb-MXenes akan lokaci da kuma hana ci gaban da ba a saba gani ba, manufar bincikenmu ita ce bincika hanyoyin aiki da za a iya yi. Lokacin da halittu kamar algae suka fallasa ga mahaɗan ko kayan da ba su saba da yanayin halittunsu ba, suna iya amsawa ta hanyoyi daban-daban58,59. Idan babu gubar ƙarfe mai guba, ƙananan ƙwayoyin cuta na iya ciyar da kansu, wanda ke ba su damar girma akai-akai60. Bayan shan abubuwa masu guba, ana iya kunna hanyoyin kariya, kamar canza siffa ko siffa. Dole ne kuma a yi la'akari da yuwuwar sha58,59. Abin lura, duk wata alama ta hanyar kariya alama ce bayyananniya ta gubar mahaɗan gwaji. Saboda haka, a cikin ƙarin aikinmu, mun bincika yuwuwar hulɗar saman tsakanin nanoflakes na SL Nb-MXene da microalgae ta SEM da yuwuwar sha MXene mai tushen Nb ta hanyar X-ray fluorescence spectroscopy (XRF). Lura cewa an yi nazarin SEM da XRF ne kawai a mafi girman taro na MXene don magance matsalolin gubar aiki.
An nuna sakamakon SEM a cikin Hoto na 4. Kwayoyin algae marasa magani (duba Hoto na 4a, samfurin tunani) a bayyane yake nuna yanayin halittar R. subcapitata da siffar ƙwayoyin croissant. Kwayoyin suna bayyana a kwance kuma ba su da tsari. Wasu ƙwayoyin algae sun haɗu suka haɗu da juna, amma wannan wataƙila ya faru ne sakamakon tsarin shirya samfurin. Gabaɗaya, ƙwayoyin algae tsarkakakku suna da saman santsi kuma ba su nuna wani canji na siffa ba.
Hotunan SEM suna nuna hulɗar saman tsakanin ƙananan ƙwayoyin algae da nanosheets na MXene bayan sa'o'i 72 na hulɗa a cikin babban taro (100 MG L-1). (a) Ƙananan ƙwayoyin algae kore marasa magani bayan hulɗa da SL (b) Nb2CTx da (c) Nb4C3TX MXenes. Lura cewa an yiwa Nb-MXene nanoflakes alama da kibiyoyi ja. Don kwatantawa, an kuma ƙara hotuna daga na'urar hangen nesa.
Sabanin haka, ƙwayoyin ƙwayoyin halitta masu ƙananan ƙwayoyin halitta waɗanda SL Nb-MXene nanoflakes suka shafa sun lalace (duba Hoto na 4b, c, kibiyoyi ja). A yanayin Nb2CTx MXene (Hoto na 4b), ƙwayoyin halitta masu ƙananan ƙwayoyin halitta suna girma tare da nanoscales masu girma biyu da aka haɗa, waɗanda zasu iya canza yanayin halittarsu. Abin lura, mun kuma lura da waɗannan canje-canjen a ƙarƙashin na'urar hangen nesa mai haske (duba Hoto na SI S11 don ƙarin bayani). Wannan canjin yanayin halitta yana da tushe mai yiwuwa a cikin ilimin halittar ƙwayoyin halitta da ikonsu na kare kansu ta hanyar canza yanayin halittar ƙwayoyin halitta, kamar ƙara yawan ƙwayoyin halitta 61. Saboda haka, yana da mahimmanci a duba adadin ƙwayoyin halitta masu ƙananan ƙwayoyin halitta waɗanda a zahiri suke hulɗa da Nb-MXenes. Nazarin SEM ya nuna cewa kusan kashi 52% na ƙwayoyin halitta masu ƙananan ƙwayoyin halitta sun fallasa ga Nb-MXenes, yayin da kashi 48% na waɗannan ƙwayoyin halitta masu ƙananan ƙwayoyin halitta suka guji hulɗa. Ga SL Nb4C3Tx MXene, ƙananan ƙwayoyin cuta suna ƙoƙarin guje wa hulɗa da MXene, ta haka suna gano wuri da girma daga ƙananan ƙwayoyin cuta masu girma biyu (Hoto na 4c). Duk da haka, ba mu lura da shigar ƙwayoyin cuta cikin ƙwayoyin cuta masu yawa da lalacewarsu ba.
Kiyaye kai kuma dabi'a ce ta mayar da martani ga toshewar photosynthesis saboda shaƙar ƙwayoyin cuta a saman tantanin halitta da kuma abin da ake kira tasirin inuwa (shading)62. A bayyane yake cewa kowane abu (misali, nanoflakes na Nb-MXene) wanda ke tsakanin ƙananan algae da tushen haske yana iyakance adadin hasken da chloroplasts ke sha. Duk da haka, ba mu da shakka cewa wannan yana da tasiri mai mahimmanci akan sakamakon da aka samu. Kamar yadda aka nuna ta hanyar bincikenmu na ƙananan algae, nanoflakes na 2D ba a naɗe su gaba ɗaya ko manne su a saman ƙananan algae ba, koda lokacin da ƙwayoyin ƙananan algae ke hulɗa da Nb-MXenes. Madadin haka, nanoflakes sun zama sun mayar da hankali ga ƙwayoyin ƙananan algae ba tare da rufe saman su ba. Irin wannan saitin nanoflakes/microalgae ba zai iya iyakance adadin hasken da ƙwayoyin ƙananan algae ke sha sosai ba. Bugu da ƙari, wasu bincike sun nuna cewa an samu ci gaba a sha haske ta hanyar amfani da kwayoyin halitta masu daukar hoto idan aka kwatanta da nanomaterials masu girma biyu63,64,65,66.
Tunda hotunan SEM ba za su iya tabbatar da ɗaukar niobium kai tsaye ta ƙwayoyin algae ba, ƙarin bincikenmu ya koma ga nazarin hasken X-ray (XRF) da kuma nazarin X-ray photoelectron spectroscopy (XPS) don fayyace wannan batu. Saboda haka, mun kwatanta ƙarfin kololuwar Nb na samfuran microalgae waɗanda ba su yi mu'amala da MXenes ba, nanoflakes na MXene da aka ware daga saman ƙwayoyin microalgae, da ƙwayoyin microalgal bayan cire MXenes da aka haɗa. Ya kamata a lura cewa idan babu Nb, ƙimar Nb da ƙwayoyin microalgae suka samu ya kamata ya zama sifili bayan cire nanoscales da aka haɗa. Saboda haka, idan Nb ya faru, sakamakon XRF da XPS ya kamata ya nuna kololuwar Nb bayyananne.
A yanayin XRF spectra, samfuran ƙananan ƙwayoyin halitta sun nuna kololuwar Nb don SL Nb2CTx da Nb4C3Tx MXene bayan hulɗa da SL Nb2CTx da Nb4C3Tx MXene (duba Hoto na 5a, kuma lura cewa an nuna sakamakon MAX da ML MXenes a cikin SI, Hoto na S12–C17). Abin sha'awa, ƙarfin kololuwar Nb iri ɗaya ne a duka biyun (sandunan ja a cikin Hoto na 5a). Wannan ya nuna cewa algae ba zai iya shan Nb fiye da haka ba, kuma an sami matsakaicin ƙarfin tarin Nb a cikin ƙwayoyin halitta, kodayake an haɗa Nb4C3Tx MXene sau biyu a cikin ƙwayoyin ƙwayoyin halitta (sandunan shuɗi a cikin Hoto na 5a). Abin lura, ikon ƙananan ƙwayoyin halitta don shan ƙarfe ya dogara ne akan yawan ƙwayoyin ƙarfe a cikin muhalli67,68. Shamshada et al.67 sun gano cewa ƙarfin shan algae na ruwan sha yana raguwa tare da ƙaruwar pH. Raize da abokan aikinsa 68 sun lura cewa ikon ruwan teku na shan ƙarfe ya fi kusan kashi 25% girma ga Pb2+ fiye da na Ni2+.
(a) Sakamakon XRF na shan ƙwayoyin algae kore masu launin kore waɗanda aka saka a cikin wani babban taro na ƙwayoyin algae masu launin SL Nb-MXenes (100 mg L-1) na tsawon awanni 72. Sakamakon ya nuna kasancewar α a cikin ƙwayoyin algae masu tsarki (samfurin sarrafawa, ginshiƙan launin toka), nanoflakes na D2D waɗanda aka ware daga ƙwayoyin algae masu launin shuɗi (ginshiƙan shuɗi), da ƙwayoyin algae masu launin shuɗi bayan rabuwa da nanoflakes na D2D daga saman (ginshiƙan ja). Adadin abubuwan da ke cikin Nb, (b) kashi na sinadaran da ke cikin abubuwan da ke cikin ƙwayoyin algae masu launin shuɗi (C=O da CHx/C–O) da oxides na Nb da ke cikin ƙwayoyin algae bayan haɗuwa da SL Nb-MXenes, (c–e) Daidaita kololuwar haɗin XPS SL Nb2CTx spectra da (fh) SL Nb4C3Tx MXene da ƙwayoyin algae suka shiga ciki.
Saboda haka, mun yi tsammanin ƙwayoyin algae za su iya sha Nb ta hanyar ƙwayoyin oxides. Don gwada wannan, mun yi nazarin XPS kan ƙwayoyin MXenes Nb2CTx da Nb4C3TX da algae. Sakamakon hulɗar microalgae da Nb-MXenes da MXenes da aka ware daga ƙwayoyin algae an nuna su a cikin Hoto na 5b. Kamar yadda aka zata, mun gano kololuwar Nb 3d a cikin samfuran microalgae bayan cire MXene daga saman ƙwayoyin algae. An ƙididdige ƙimar ƙayyade C=O, CHx/CO, da Nb oxides bisa ga siginar Nb 3d, O 1s, da C 1s da aka samu tare da Nb2CTx SL (Hoto na 5c–e) da Nb4C3Tx SL (Hoto na 5c–e). ) da aka samu daga ƙwayoyin algae da aka haɗa. Hoto na 5f–h) MXenes. Tebur S1-3 yana nuna cikakkun bayanai game da sigogin kololuwa da kuma gabaɗayan sunadarai da suka samo asali daga dacewa. Abin lura ne cewa yankunan Nb 3d na Nb2CTx SL da Nb4C3Tx SL (Hoto na 5c, f) sun yi daidai da wani ɓangare na Nb2O5. A nan, ba mu sami kololuwar da ta shafi MXene a cikin bakan ba, wanda ke nuna cewa ƙwayoyin microalgae suna shan sifar oxide ta Nb kawai. Bugu da ƙari, mun yi kimanin bakan C 1 tare da abubuwan C-C, CHx/C-O, C=O, da –COOH. Mun sanya kololuwar CHx/C–O da C=O ga gudummawar kwayoyin microalgae. Waɗannan abubuwan kwayoyin halitta sun kai kashi 36% da 41% na kololuwar C 1s a cikin Nb2CTx SL da Nb4C3TX SL, bi da bi. Sannan muka sanya bakan O 1s na SL Nb2CTx da SL Nb4C3TX tare da Nb2O5, abubuwan kwayoyin halitta na microalgae (CHx/CO), da kuma ruwan da aka sha a saman.
A ƙarshe, sakamakon XPS ya nuna a sarari siffar Nb, ba kawai kasancewarsa ba. Dangane da matsayin siginar Nb 3d da sakamakon rabuwar, mun tabbatar da cewa Nb yana sha ne kawai a cikin nau'in oxides ba ions ko MXene kanta ba. Bugu da ƙari, sakamakon XPS ya nuna cewa ƙwayoyin microalgae suna da ikon ɗaukar Nb oxides daga SL Nb2CTx idan aka kwatanta da SL Nb4C3TX MXene.
Duk da cewa sakamakon ɗaukar Nb ɗinmu yana da ban sha'awa kuma yana ba mu damar gano lalacewar MXene, babu wata hanya da ake da ita don bin diddigin canje-canjen siffar da ke da alaƙa da su a cikin nanoflakes na 2D. Saboda haka, mun kuma yanke shawarar ƙirƙirar wata hanya mai dacewa wadda za ta iya mayar da martani kai tsaye ga duk wani canji da ke faruwa a cikin nanoflakes na 2D Nb-MXene da ƙwayoyin microalgae. Yana da mahimmanci a lura cewa muna ɗauka cewa idan nau'ikan da ke hulɗa suna fuskantar kowane canji, rugujewa ko raguwar rarrabuwa, wannan ya kamata ya bayyana da sauri a matsayin canje-canje a cikin sigogin siffa, kamar diamita na daidai yankin zagaye, zagaye, faɗin Feret, ko tsawon Feret. Tunda waɗannan sigogi sun dace da bayyana barbashi masu tsayi ko nanoflakes masu girma biyu, bin diddigin su ta hanyar nazarin siffar barbashi mai ƙarfi zai ba mu bayanai masu mahimmanci game da canjin siffar nanoflakes na SL Nb-MXene yayin raguwa.
An nuna sakamakon da aka samu a Hoto na 6. Don kwatantawa, mun kuma gwada matakin MAX na asali da ML-MXenes (duba Siffofin SI S18 da S19). Nazarin yanayin siffa na barbashi ya nuna cewa duk sigogin siffa na SL guda biyu na Nb-MXene sun canza sosai bayan hulɗa da ƙananan algae. Kamar yadda aka nuna ta hanyar ma'aunin diamita na yanki mai zagaye daidai (Hoto na 6a, b), raguwar ƙarfin kololuwar ɓangaren manyan nanoflakes yana nuna cewa suna iya ruɓewa zuwa ƙananan gutsuttsura. A kan Hoto na 6c, d yana nuna raguwar kololuwar da ke da alaƙa da girman juzu'i na flakes (tsawo na nanoflakes), yana nuna canjin nanoflakes na 2D zuwa siffar da ta fi kama da barbashi. Hoto na 6e-h yana nuna faɗi da tsawon na Feret, bi da bi. Faɗin Feret da tsawon sigogi ne masu dacewa kuma ya kamata a yi la'akari da su tare. Bayan ƙunsar nanoflakes na 2D Nb-MXene a gaban ƙananan algae, kololuwar haɗin Feret ɗinsu ta canza kuma ƙarfinsu ya ragu. Bisa ga waɗannan sakamakon tare da haɗin gwiwar yanayin halitta, XRF da XPS, mun kammala da cewa canje-canjen da aka lura suna da alaƙa da iskar shaka yayin da MXenes masu oxidized ke ƙara wrinkles kuma suna rushewa zuwa gutsuttsura da ƙwayoyin oxide masu siffar ƙwallo69,70.
Binciken sauyin MXene bayan hulɗa da ƙananan ƙwayoyin halitta masu launin kore. Binciken siffar ƙwayoyin halitta masu ƙarfi yana la'akari da sigogi kamar (a, b) diamita na yankin zagaye mai daidai, (c, d) zagaye, (e, f) faɗin Feret da (g, h) Tsawon Feret. Don wannan, an yi nazarin samfuran ƙananan ƙwayoyin halitta guda biyu tare da manyan ƙwayoyin halitta na SL Nb2CTx da SL Nb4C3Tx MXenes, ƙananan ƙwayoyin halitta masu launin kore, da ƙananan ƙwayoyin halitta masu launin kore SL Nb2CTx da SL Nb4C3Tx MXenes. Kibiyoyi ja suna nuna sauye-sauyen sigogin siffar ƙananan ƙwayoyin halitta masu girman biyu da aka yi nazari a kansu.
Tunda binciken sigogin siffa abin dogaro ne sosai, yana iya bayyana canje-canjen siffofi a cikin ƙwayoyin algae. Saboda haka, mun yi nazarin daidai diamita na yanki mai zagaye, zagaye, da faɗin/tsawon Feret na ƙwayoyin algae tsarkakakku da ƙwayoyin bayan hulɗa da nanoflakes na 2D Nb. A hoto na 6a–h yana nuna canje-canje a cikin sigogin siffa na ƙwayoyin algae, kamar yadda aka nuna ta hanyar raguwar ƙarfin kololuwa da kuma canjin matsakaicin zuwa manyan ƙima. Musamman ma, sigogin zagaye na ƙwayoyin halitta sun nuna raguwar ƙwayoyin da suka daɗe da kuma ƙaruwa a cikin ƙwayoyin masu zagaye (Hoto na 6a, b). Bugu da ƙari, faɗin ƙwayoyin Feret ya ƙaru da micrometers da yawa bayan hulɗa da SL Nb2CTx MXene (Hoto na 6e) idan aka kwatanta da SL Nb4C3TX MXene (Hoto na 6f). Muna zargin cewa wannan na iya faruwa ne saboda ƙarfin ɗaukar Nb oxides ta hanyar microalgae lokacin hulɗa da Nb2CTx SR. Ƙarancin haɗa flakes na Nb zuwa saman su na iya haifar da haɓakar ƙwayoyin tare da ƙarancin tasirin inuwa.
Abubuwan da muka lura da su na canje-canje a cikin sigogin siffa da girman ƙananan ƙwayoyin cuta suna ƙara wa wasu bincike. Ƙananan ƙwayoyin cuta na kore na iya canza yanayin halittarsu dangane da damuwar muhalli ta hanyar canza girman ƙwayoyin halitta, siffa ko metabolism61. Misali, canza girman ƙwayoyin halitta yana sauƙaƙa shan abubuwan gina jiki71. Ƙananan ƙwayoyin algae suna nuna ƙarancin shan abubuwan gina jiki da raguwar saurin girma. Akasin haka, manyan ƙwayoyin cuta suna cin ƙarin abubuwan gina jiki, waɗanda daga baya ake adana su a cikin ƙwayoyin halitta72,73. Machado da Soares sun gano cewa triclosan mai kashe ƙwayoyin cuta na iya ƙara girman ƙwayoyin halitta. Sun kuma sami manyan canje-canje a cikin siffar algae74. Bugu da ƙari, Yin et al.9 sun kuma bayyana canje-canje a cikin ƙwayoyin cuta bayan fallasa ga raguwar graphene oxide nanocomposites. Saboda haka, a bayyane yake cewa canjin sigogin girma/siffar ƙwayoyin cuta yana faruwa ne sakamakon kasancewar MXene. Tunda wannan canjin girma da siffa yana nuna canje-canje a cikin shan abubuwan gina jiki, mun yi imanin cewa nazarin sigogin girma da siffa akan lokaci na iya nuna shan niobium oxide ta microalgae a gaban Nb-MXenes.
Bugu da ƙari, ana iya haɗa MXenes a gaban algae. Dalai et al.75 sun lura cewa yanayin algae kore da aka fallasa ga nano-TiO2 da Al2O376 bai kasance iri ɗaya ba. Duk da cewa abubuwan da muka lura sun yi kama da na wannan binciken, yana da alaƙa ne kawai da nazarin tasirin bioremediation dangane da samfuran lalata MXene a gaban nanoflakes 2D ba nanoparticles ba. Tunda MXenes na iya lalacewa zuwa ƙarfe oxides, 31,32,77,78 yana da kyau a ɗauka cewa nanoflakes ɗinmu na Nb suma na iya samar da Nb oxides bayan mu'amala da ƙwayoyin microalgae.
Domin bayyana rage nanoflakes na 2D-Nb ta hanyar tsarin rugujewa bisa ga tsarin oxidation, mun gudanar da bincike ta amfani da na'urar hangen nesa ta lantarki mai ƙuduri mai girma (HRTEM) (Hoto na 7a,b) da kuma na'urar hangen nesa ta X-ray (XPS) (Hoto na 7). 7c-i da tebura S4-5). Duk hanyoyin biyu sun dace da nazarin oxidation na kayan 2D da kuma haɗa juna. HRTEM tana iya nazarin lalacewar tsarin masu girman biyu da kuma bayyanar nanoparticles na oxide na ƙarfe daga baya, yayin da XPS ke da alaƙa da haɗin saman. Don wannan dalili, mun gwada nanoflakes na 2D Nb-MXene da aka cire daga ƙwayoyin microalgae, wato, siffarsu bayan hulɗa da ƙwayoyin microalgae (duba Hoto na 7).
Hotunan HRTEM da ke nuna yanayin oxidized (a) SL Nb2CTx da (b) SL Nb4C3Tx MXenes, sakamakon nazarin XPS da ke nuna (c) abun da ke cikin samfuran oxidation bayan raguwa, (d–f) daidaita kololuwar abubuwan da ke cikin XPS na SL Nb2CTx da (g–i) An gyara Nb4C3Tx SL da ƙwayoyin kore.
Nazarin HRTEM ya tabbatar da iskar shaka ta nau'ikan nanoflakes guda biyu na Nb-MXene. Duk da cewa nanoflakes sun riƙe siffarsu ta girma biyu zuwa wani mataki, iskar shaka ta haifar da bayyanar nanoparticles da yawa da suka rufe saman nanoflakes na MXene (duba Hoto na 7a,b). Binciken XPS na siginar c Nb 3d da O 1s ya nuna cewa an samar da Nb oxides a duka biyun. Kamar yadda aka nuna a Hoto na 7c, 2D MXene Nb2CTx da Nb4C3TX suna da siginar Nb 3d wanda ke nuna kasancewar NbO da Nb2O5 oxides, yayin da siginar O 1s ke nuna adadin haɗin O-Nb da ke da alaƙa da aikin saman nanoflake na 2D. Mun lura cewa gudummawar Nb oxide tana da rinjaye idan aka kwatanta da Nb-C da Nb3+-O.
A kan siffa ta 7g–i, an nuna siffa ta XPS ta Nb 3d, C 1s, da O 1s SL Nb2CTx (duba Siffa ta 7d–f) da SL Nb4C3TX MXene da aka ware daga ƙwayoyin microalgae. An bayar da cikakkun bayanai game da sigogin kololuwar Nb-MXenes a cikin Tebur S4–5, bi da bi. Da farko mun yi nazarin abun da ke cikin Nb 3d. Sabanin Nb da ƙwayoyin microalgae suka sha, a cikin MXene da aka ware daga ƙwayoyin microalgae, banda Nb2O5, an sami wasu abubuwan haɗin. A cikin Nb2CTx SL, mun lura da gudummawar Nb3+-O a cikin adadin 15%, yayin da sauran siffa ta Nb 3d ta mamaye Nb2O5 (85%). Bugu da ƙari, samfurin SL Nb4C3TX ya ƙunshi abubuwan Nb-C (9%) da Nb2O5 (91%). A nan Nb-C ya fito ne daga yadudduka guda biyu na ƙarfe mai kama da carbide a cikin Nb4C3Tx SR. Sannan mu tsara siginar C 1s zuwa sassa huɗu daban-daban, kamar yadda muka yi a cikin samfuran da aka haɗa cikin ciki. Kamar yadda aka zata, siginar C 1s ta mamaye carbon mai kama da graphitic, sannan kuma gudummawa daga barbashi na halitta (CHx/CO da C=O) daga ƙwayoyin microalgae. Bugu da ƙari, a cikin siginar O 1s, mun lura da gudummawar nau'ikan ƙwayoyin microalgae, niobium oxide, da ruwan da aka haɗa.
Bugu da ƙari, mun bincika ko rabuwar Nb-MXenes yana da alaƙa da kasancewar nau'in iskar oxygen mai amsawa (ROS) a cikin ƙwayoyin abinci masu gina jiki da/ko ƙananan ƙwayoyin algae. Don wannan dalili, mun tantance matakan iskar oxygen singlet (1O2) a cikin tsakiyar al'ada da glutathione na cikin ƙwayoyin halitta, thiol wanda ke aiki a matsayin antioxidant a cikin ƙananan ƙwayoyin algae. An nuna sakamakon a cikin SI (Hotunan S20 da S21). Al'adun da ke da SL Nb2CTx da Nb4C3TX MXenes an siffanta su da raguwar adadin 1O2 (duba Hoto na S20). A yanayin SL Nb2CTx, an rage MXene 1O2 zuwa kusan 83%. Ga al'adun ƙananan ƙwayoyin algae da ke amfani da SL, Nb4C3TX 1O2 ya ragu sosai, zuwa 73%. Abin sha'awa, canje-canje a cikin 1O2 sun nuna irin wannan yanayin kamar yadda aka lura a baya tasirin hana-ƙarfafawa (duba Hoto na 3). Ana iya jayayya cewa haɗuwa a cikin haske mai haske na iya canza photooxidation. Duk da haka, sakamakon binciken sarrafawa ya nuna kusan matakan 1O2 akai-akai a lokacin gwajin (Hoto na S22). A yanayin matakan ROS na cikin ƙwayoyin halitta, mun kuma lura da irin wannan yanayin raguwa (duba Hoto na S21). Da farko, matakan ROS a cikin ƙwayoyin microalgae da aka haɓaka a gaban Nb2CTx da Nb4C3Tx SLs sun wuce matakan da aka samu a cikin al'adun microalgae tsarkakakku. Daga ƙarshe, duk da haka, ya bayyana cewa ƙananan algae sun dace da kasancewar Nb-MXenes duka, yayin da matakan ROS suka ragu zuwa 85% da 91% na matakan da aka auna a cikin al'adun microalgae tsarkakakku da aka yi wa allurar SL Nb2CTx da Nb4C3TX, bi da bi. Wannan na iya nuna cewa ƙananan algae suna jin daɗi a kan lokaci a gaban Nb-MXene fiye da a cikin matsakaiciyar abinci kawai.
Microalgae rukuni ne na halittu masu amfani da hasken rana. A lokacin photosynthesis, suna canza iskar carbon dioxide (CO2) zuwa carbon na halitta. Samfuran photosynthesis sune glucose da oxygen79. Muna zargin cewa iskar oxygen da aka samar ta haka tana taka muhimmiyar rawa wajen samar da iskar oxygen na Nb-MXenes. Wata hanyar da za a iya bayyana hakan ita ce cewa sigar iskar oxygen ta bambanta tana samuwa ne a matsin lamba mai ƙanƙanta da babban ɓangaren oxygen a waje da cikin nanoflakes na Nb-MXene. Wannan yana nufin cewa duk inda akwai wurare daban-daban na matsin lamba na oxygen, yankin da ke da mafi ƙarancin matakin zai samar da anode 80, 81, 82. A nan, microalgae suna ba da gudummawa ga ƙirƙirar ƙwayoyin da ke da iskar oxygen daban-daban a saman flakes na MXene, waɗanda ke samar da iskar oxygen saboda halayensu na photosynthesis. Sakamakon haka, ana samar da samfuran biocorrosion (a wannan yanayin, niobium oxides). Wani al'amari kuma shi ne cewa microalgae na iya samar da acid na halitta waɗanda aka saki a cikin ruwa83,84. Saboda haka, ana samar da yanayi mai tsauri, ta haka ne ake canza Nb-MXenes. Bugu da ƙari, ƙananan algae na iya canza pH na muhalli zuwa alkaline saboda shan carbon dioxide, wanda kuma zai iya haifar da tsatsa79.
Mafi mahimmanci, hasken rana mai duhu/haske da aka yi amfani da shi a cikin bincikenmu yana da mahimmanci don fahimtar sakamakon da aka samu. An bayyana wannan fanni dalla-dalla a cikin Djemai-Zoglache et al. 85 Sun yi amfani da hasken rana mai tsawon awa 12/12 da gangan don nuna lalacewar halittu da ke da alaƙa da gurɓataccen halittu ta hanyar ƙwayoyin halittar da ke ɗauke da jan ƙwayoyin halittar Porphyridium purpureum. Sun nuna cewa hasken rana yana da alaƙa da juyin halittar yuwuwar ba tare da lalata halittu ba, yana bayyana kansa a matsayin oscillations na pseudoperiodic a kusa da ƙarfe 24:00. Dowling et al. sun tabbatar da waɗannan abubuwan lura 86 Sun nuna hotunan biosynthetic na cyanobacteria Anabaena. Iskar oxygen da aka narke ana samar da ita a ƙarƙashin aikin haske, wanda ke da alaƙa da canji ko canzawa a cikin ikon lalata halittu kyauta. Muhimmancin hasken rana yana da mahimmanci ta hanyar gaskiyar cewa ikon lalata halittu yana ƙaruwa a cikin yanayin haske kuma yana raguwa a cikin yanayin duhu. Wannan ya faru ne saboda iskar oxygen da ƙwayoyin halitta masu amfani da hasken rana ke samarwa, wanda ke tasiri ga amsawar cathodic ta hanyar matsin lamba na ɓangare da aka samar kusa da na'urorin lantarki87.
Bugu da ƙari, an yi gwajin Fourier transform infrared spectroscopy (FTIR) don gano ko akwai wani canji a cikin sinadaran ƙwayoyin algae bayan hulɗa da Nb-MXenes. Waɗannan sakamakon da aka samu suna da rikitarwa kuma mun gabatar da su a cikin SI (Hotuna S23-S25, gami da sakamakon matakin MAX da MXenes ML). A takaice, ƙididdigar da aka samu na ƙananan algae suna ba mu muhimman bayanai game da halayen sinadarai na waɗannan halittu. Waɗannan girgiza mafi yuwuwar suna samuwa a mita na 1060 cm-1 (CO), 1540 cm-1, 1640 cm-1 (C=C), 1730 cm-1 (C=O), 2850 cm-1, 2920 cm-1. ɗaya. 1 1 (C–H) da 3280 cm-1 (O–H). Ga SL Nb-MXenes, mun sami sa hannun shimfiɗa CH-bond wanda ya yi daidai da bincikenmu na baya38. Duk da haka, mun lura cewa wasu ƙarin kololuwa da ke da alaƙa da haɗin C=C da CH sun ɓace. Wannan yana nuna cewa sinadaran da ke cikin ƙananan algae na iya fuskantar ƙananan canje-canje saboda hulɗa da SL Nb-MXenes.
Idan ana la'akari da yiwuwar canje-canje a cikin biochemistry na ƙananan ƙwayoyin halitta, ya kamata a sake duba tarin ƙwayoyin halitta marasa tsari, kamar niobium oxide,59. Yana da hannu wajen ɗaukar ƙarfe ta saman ƙwayar halitta, jigilar su zuwa cikin cytoplasm, alaƙarsu da ƙungiyoyin carboxyl na cikin ƙwayoyin halitta, da kuma tarin su a cikin ƙananan ƙwayoyin halitta polyphosphosomes20,88,89,90. Bugu da ƙari, ana kiyaye alaƙar da ke tsakanin ƙananan ƙwayoyin halitta da ƙarfe ta hanyar ƙungiyoyin ƙwayoyin halitta masu aiki. Saboda wannan dalili, sha kuma ya dogara ne akan sinadaran saman ƙwayoyin halitta, wanda yake da rikitarwa sosai9,91. Gabaɗaya, kamar yadda aka zata, sinadaran ƙwayoyin halitta marasa tsari sun ɗan canza kaɗan saboda sha Nb oxide.
Abin sha'awa, an fara ganin hana ƙwayoyin cuta na microgae a matsayin abin da zai iya jurewa a tsawon lokaci. Kamar yadda muka lura, ƙwayoyin cuta na microgae sun shawo kan canjin muhalli na farko kuma daga ƙarshe sun koma ga yawan girma na yau da kullun har ma sun ƙaru. Nazarin yuwuwar zeta yana nuna babban kwanciyar hankali lokacin da aka shigar da su cikin hanyoyin gina jiki. Don haka, an ci gaba da hulɗar saman tsakanin ƙwayoyin ƙwayoyin cuta na microgae da nanoflakes na Nb-MXene a duk tsawon gwaje-gwajen ragewa. A cikin ƙarin bincikenmu, mun taƙaita manyan hanyoyin aiki waɗanda ke ƙarƙashin wannan halayyar microgae mai ban mamaki.
Abubuwan da aka lura da SEM sun nuna cewa ƙananan ƙwayoyin cuta suna haɗuwa da Nb-MXenes. Ta amfani da nazarin hotuna masu motsi, mun tabbatar da cewa wannan tasirin yana haifar da canza ƙwayoyin cuta masu girma biyu na Nb-MXene zuwa ƙwayoyin halitta masu siffar ƙwallo, ta haka yana nuna cewa rugujewar ƙwayoyin cuta na nanoflakes yana da alaƙa da iskar shakansu. Don gwada hasashenmu, mun gudanar da jerin nazarin kayan aiki da na sinadarai. Bayan gwaji, ƙwayoyin cuta na nanoflakes sun yi oxidized a hankali suka bazu zuwa samfuran NbO da Nb2O5, wanda bai haifar da barazana ga ƙwayoyin cuta na kore ba. Ta amfani da lura da FTIR, ba mu sami wani muhimmin canji a cikin sinadaran ƙwayoyin cuta na ƙwayoyin cuta da aka haɗa a gaban ƙwayoyin cuta na 2D Nb-MXene ba. Idan aka yi la'akari da yuwuwar shan ƙwayoyin cuta na niobium oxide ta hanyar ƙwayoyin cuta, mun yi nazarin hasken X-ray. Waɗannan sakamakon sun nuna a sarari cewa ƙwayoyin cuta na microgae da aka yi nazari a kansu suna ciyar da ƙwayoyin cuta na niobium oxides (NbO da Nb2O5), waɗanda ba su da guba ga ƙwayoyin cuta na microgae da aka yi nazari a kansu.