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Kukula kofulumira kwa nanotechnology ndi kuphatikizidwa kwake muzogwiritsira ntchito tsiku ndi tsiku kungawononge chilengedwe.Ngakhale njira zobiriwira zowonongera zonyansa za organic zakhazikitsidwa bwino, kubwezeretsanso zonyansa za crystalline za inorganic ndizodetsa nkhawa kwambiri chifukwa cha kuchepa kwawo kwa biotransformation komanso kusamvetsetsa kuyanjana kwa zinthu zakuthambo ndi zachilengedwe.Pano, timagwiritsa ntchito Nb-based inorganic 2D MXenes model pamodzi ndi njira yosavuta yowunikira mawonekedwe kuti tifufuze njira ya bioremediation ya 2D ceramic nanomaterials ndi green microalgae Raphidocelis subcapitata.Tinapeza kuti ma microalgae amawononga Nb-based MXenes chifukwa cha kuyanjana kwa physico-chemical mankhwala.Poyambirira, ma nanoflakes amtundu umodzi ndi ma multilayer MXene adalumikizidwa pamwamba pa ndere, zomwe zidachepetsa kukula kwa algae.Komabe, pakulumikizana kwanthawi yayitali ndi pamwamba, ma microalgae oxidized MXene nanoflakes ndikuwolanso kukhala NbO ndi Nb2O5.Chifukwa ma oxides awa sakhala poizoni kwa ma cell a algae, amadya ma nanoparticles a Nb oxide pogwiritsa ntchito njira yoyamwitsa yomwe imabwezeretsanso ma microalgae pambuyo pa maola 72 akumwa madzi.Zotsatira za zakudya zomwe zimagwirizanitsidwa ndi kuyamwa zimawonekeranso pakuwonjezeka kwa maselo, mawonekedwe awo osalala komanso kusintha kwa kukula.Kutengera zomwe tapezazi, timatsimikiza kuti kukhalapo kwakanthawi kochepa komanso kwakanthawi kwa ma MXenes a Nb m'madzi am'madzi amchere kungayambitse zovuta zazing'ono zachilengedwe.Ndizofunikira kudziwa kuti, pogwiritsa ntchito ma nanomatadium okhala ndi mbali ziwiri monga machitidwe achitsanzo, tikuwonetsa kuthekera kotsata masinthidwe a mawonekedwe ngakhale muzinthu zowoneka bwino.Ponseponse, kafukufukuyu akuyankha funso lofunika kwambiri lokhudzana ndi kuyanjana kwapamtunda komwe kumayendetsa makina a bioremediation a 2D nanomaterials ndipo amapereka maziko ophunzirira kwakanthawi kochepa komanso kwakanthawi kokhudzana ndi chilengedwe cha ma inorganic crystalline nanomaterials.
Ma Nanomaterials apanga chidwi kwambiri kuyambira pomwe adapezeka, ndipo ma nanotechnologies osiyanasiyana alowa mu gawo lamakono1.Tsoka ilo, kuphatikiza kwa nanomatadium m'mapulogalamu atsiku ndi tsiku kungayambitse kutulutsidwa mwangozi chifukwa cha kutaya kosayenera, kusamalidwa mosasamala, kapena chitetezo chokwanira.Choncho, n'zomveka kuganiza kuti nanomatadium, kuphatikizapo awiri-dimensional (2D) nanomaterials, akhoza kumasulidwa ku chilengedwe, khalidwe ndi ntchito zamoyo zomwe sizikumveka bwino.Choncho, n'zosadabwitsa kuti nkhawa za ecotoxicity zakhala zikuyang'ana pa luso la 2D nanomaterials kuti lilowe mu machitidwe a m'madzi2,3,4,5,6.Muzachilengedwe izi, ma nanomatadium ena a 2D amatha kulumikizana ndi zamoyo zosiyanasiyana pamilingo yosiyanasiyana ya trophic, kuphatikiza ma microalgae.
Microalgae ndi zamoyo zakale zomwe zimapezeka mwachilengedwe m'madzi opanda mchere komanso zam'madzi zomwe zimapanga mankhwala osiyanasiyana kudzera mu photosynthesis7.Momwemo, ndizofunika kwambiri pazamoyo zam'madzi8,9,10,11,12 koma zimakhalanso zovuta, zotsika mtengo komanso zogwiritsidwa ntchito mofala za ecotoxicity13,14.Popeza maselo a microalgae amachulukana mofulumira ndipo mwamsanga amayankha kukhalapo kwa mankhwala osiyanasiyana, akulonjeza kuti pakhale njira zowononga zachilengedwe zochizira madzi okhudzidwa ndi zinthu zamoyo15,16.
Maselo a algae amatha kuchotsa ma ion mumadzi kudzera mu biosorption ndi accumulation17,18.Mitundu ina ya algal monga Chlorella, Anabaena invar, Westiellopsis prolifica, Stigeoclonium tenue ndi Synechococcus sp.Zapezeka kuti zimanyamula komanso kudyetsa ayoni achitsulo oopsa monga Fe2+, Cu2+, Zn2+ ndi Mn2+19.Kafukufuku wina wasonyeza kuti Cu2+, Cd2+, Ni2+, Zn2+ kapena Pb2+ ions amachepetsa kukula kwa Scenedesmus mwa kusintha ma cell morphology ndi kuwononga ma chloroplasts20,21.
Njira zobiriwira zowonongera zowononga zachilengedwe komanso kuchotsa ma ayoni azitsulo zolemera zakopa chidwi cha asayansi ndi mainjiniya padziko lonse lapansi.Izi makamaka chifukwa chakuti zonyansazi mosavuta kukonzedwa mu madzi gawo.Komabe, zowonongeka za crystalline zowonongeka zimadziwika ndi kusungunuka kwa madzi otsika komanso kuchepa kwa biotransformations zosiyanasiyana, zomwe zimayambitsa mavuto aakulu pakukonzanso, ndipo pang'onopang'ono zapita patsogolo m'derali22,23,24,25,26.Chifukwa chake, kufunafuna njira zothanirana ndi chilengedwe pakukonza ma nanomatadium kumakhalabe malo ovuta komanso osawerengeka.Chifukwa cha kuchuluka kwa kusatsimikizika kokhudza zotsatira za biotransformation za 2D nanomaterials, palibe njira yosavuta yodziwira njira zomwe zingawonongeke pakuchepetsa.
Mu phunziroli, tidagwiritsa ntchito algae wobiriwira ngati wogwiritsa ntchito amadzimadzi amadzimadzi amadzimadzi azinthu zadothi, kuphatikiza ndikuyang'anira momwe MXene ikuwonongeka ngati woimira zida zadothi.Mawu akuti "MXene" amasonyeza stoichiometry ya zinthu za Mn + 1XnTx, kumene M ndi zitsulo zoyamba kusintha, X ndi carbon ndi / kapena nitrogen, Tx ndi terminator pamwamba (mwachitsanzo, -OH, -F, -Cl), ndi n = 1, 2, 3 kapena 427.28.Chiyambireni kupezeka kwa Mxenes ndi Naguib et al.Sensorics, chithandizo cha khansa ndi kusefera kwa membrane 27,29,30.Kuphatikiza apo, ma MXenes amatha kuonedwa ngati machitidwe a 2D chifukwa cha kukhazikika kwawo bwino kwa colloidal komanso kuyanjana kwachilengedwe 31,32,33,34,35,36.
Choncho, njira yopangidwa m'nkhaniyi ndi malingaliro athu ofufuza akuwonetsedwa mu Chithunzi 1. Malingana ndi lingaliro ili, ma microalgae amawononga Nb-based MXenes kukhala mankhwala osagwirizana ndi mankhwala okhudzana ndi physico-chemical, omwe amalola kuti algae ayambe kuchira.Kuti ayese lingaliro ili, mamembala awiri a m'banja la niobium-based transition metal carbides ndi / kapena nitrides (MXenes), omwe ndi Nb2CTx ndi Nb4C3TX, adasankhidwa.
Njira yofufuzira ndi malingaliro ozikidwa paumboni pakuchira kwa MXene ndi green microalgae Raphidocelis subcapitata.Chonde dziwani kuti ichi ndi chithunzi chabe cha malingaliro ozikidwa pa umboni.Malo a m'nyanja amasiyana malinga ndi momwe zakudya zimagwiritsidwira ntchito komanso momwe zimakhalira (monga nthawi ya tsiku ndi tsiku komanso kuchepa kwa zakudya zofunikira).Adapangidwa ndi BioRender.com.
Choncho, pogwiritsa ntchito MXene monga dongosolo lachitsanzo, tatsegula chitseko kuti tiphunzire zamoyo zosiyanasiyana zomwe sizingawoneke ndi ma nanomatadium ena.Makamaka, tikuwonetsa kuthekera kwa bioremediation ya ma nanomaterials awiri, monga niobium-based MXenes, ndi microalgae Raphidocelis subcapitata.Ma Microalgae amatha kusokoneza Nb-MXenes mu oxidis osawononga NbO ndi Nb2O5, omwe amaperekanso zakudya kudzera mu njira yogwiritsira ntchito niobium.Ponseponse, phunziroli limayankha funso lofunikira kwambiri pazambiri zomwe zimagwirizanitsidwa ndi kuyanjana kwachilengedwe komwe kumayendetsa njira zopangira bioremediation ya ma nanomatadium amitundu iwiri.Kuphatikiza apo, tikupanga njira yosavuta yotengera mawonekedwe owonera kusintha kosawoneka bwino kwa mawonekedwe a 2D nanomaterials.Izi zimalimbikitsa kufufuza kwakanthawi kochepa komanso kwakanthawi pazovuta zosiyanasiyana zachilengedwe za inorganic crystalline nanomaterials.Choncho, phunziro lathu limawonjezera kumvetsetsa kwa mgwirizano pakati pa zinthu zakuthupi ndi zamoyo.Tikuperekanso maziko owonjezera maphunziro akanthawi kochepa komanso anthawi yayitali okhudza momwe angakhudzire zachilengedwe zamadzi opanda mchere, zomwe zitha kutsimikiziridwa mosavuta.
MXenes amaimira kalasi yosangalatsa ya zida zokhala ndi mawonekedwe apadera komanso owoneka bwino akuthupi ndi mankhwala chifukwa chake ambiri omwe atha kugwiritsa ntchito.Izi zimadalira kwambiri stoichiometry ndi chemistry ya pamwamba.Choncho, mu phunziro lathu, tinafufuza mitundu iwiri ya Nb-based hierarchical single-layer (SL) MXenes, Nb2CTx ndi Nb4C3TX, popeza zotsatira zosiyana za chilengedwe za nanomatadium zikhoza kuwonedwa.Ma MXenes amapangidwa kuchokera kuzinthu zawo zoyambira ndikuyika pamwamba-pansi pazosankha zoonda kwambiri za MAX-gawo A-zigawo.Gawo la MAX ndi ternary ceramic yopangidwa ndi "bond" midadada ya transition metal carbides ndi zigawo zoonda za "A" zinthu monga Al, Si, ndi Sn yokhala ndi MnAXn-1 stoichiometry.Mapangidwe a gawo loyambirira la MAX adawonedwa ndikusanthula ma electron microscopy (SEM) ndipo anali ogwirizana ndi maphunziro am'mbuyomu (Onani Supplementary Information, SI, Chithunzi S1).Multilayer (ML) Nb-MXene inapezedwa pambuyo pochotsa Al wosanjikiza ndi 48% HF (hydrofluoric acid).Mapangidwe a ML-Nb2CTx ndi ML-Nb4C3TX adawunikidwa ndi kusanthula ma electron microscopy (SEM) (Ziwerengero za S1c ndi S1d motsatana) ndipo mawonekedwe amtundu wa MXene adawonedwa, ofanana ndi ma nanoflakes amitundu iwiri akudutsa pobowo tating'ono.Onse a Nb-MXenes ali ofanana kwambiri ndi magawo a MXene omwe adapangidwa kale ndi acid etching27,38.Pambuyo kutsimikizira kapangidwe ka MXene, ife wosanjikiza izo ndi intercalation wa tetrabutylammonium hydroxide (TBAOH) kenako kutsuka ndi sonication, kenako tinalandira wosanjikiza umodzi kapena otsika wosanjikiza (SL) 2D Nb-MXene nanoflakes.
Tidagwiritsa ntchito ma electron microscopy (HRTEM) ndi X-ray diffraction (XRD) kuti tiyese luso la etching ndi kusenda kwina.Zotsatira za HRTEM zomwe zimagwiritsidwa ntchito pogwiritsa ntchito Inverse Fast Fourier Transform (IFFT) ndi Fast Fourier Transform (FFT) zikuwonetsedwa mu Chithunzi 2. Nb-MXene nanoflakes ankayang'ana m'mphepete kuti ayang'ane mapangidwe a atomiki ndi kuyeza mtunda wa interplanar.Zithunzi za HRTEM za MXene Nb2CTx ndi Nb4C3TX nanoflakes zinawonetsa chikhalidwe chawo chochepa kwambiri cha atomiki (onani Chithunzi 2a1, a2), monga momwe tafotokozera kale Naguib et al.27 ndi Jastrzębska et al.38.Kwa awiri oyandikana ndi Nb2CTx ndi Nb4C3Tx monolayers, tinatsimikiza mtunda wa interlayer wa 0,74 ndi 1.54 nm, motero (Mkuyu 2b1, b2), zomwe zimagwirizananso ndi zotsatira zathu zam'mbuyo38.Izi zinatsimikiziridwanso ndi kusintha kwa Fourier mofulumira (mkuyu 2c1, c2) ndi kusintha kwa Fourier mofulumira (mkuyu 2d1, d2) kusonyeza mtunda pakati pa Nb2CTx ndi Nb4C3Tx monolayers.Chithunzichi chikuwonetsa kusinthana kwa magulu owala ndi amdima ofanana ndi ma atomu a niobium ndi kaboni, zomwe zimatsimikizira kusanjika kwa ma MXenes omwe adaphunzira.Ndikofunika kudziwa kuti mawonekedwe amphamvu a X-ray spectroscopy (EDX) omwe adapezeka ku Nb2CTx ndi Nb4C3Tx (Zithunzi S2a ndi S2b) sanawonetse gawo loyambirira la MAX, popeza palibe Al peak yomwe idapezeka.
Makhalidwe a SL Nb2CTx ndi Nb4C3Tx MXene nanoflakes, kuphatikizapo (a) high resolution electron microscopy (HRTEM) mbali-view 2D nanoflake imaging ndi yolingana, (b) intensity mode, (c) inverse fast Fourier transform (IFFT), (d) fast Fourier transform (FFT-MX), (e) XB.Kwa SL 2D Nb2CTx, manambala amawonetsedwa ngati (a1, b1, c1, d1, e1).Kwa SL 2D Nb4C3Tx, manambala amawonetsedwa ngati (a2, b2, c2, d2, e1).
Miyezo ya X-ray diffraction ya SL Nb2CTx ndi Nb4C3Tx MXenes ikuwonetsedwa mu Fig.2e1 ndi e2 motsatana.Nsonga (002) pa 4.31 ndi 4.32 zimagwirizana ndi zomwe zafotokozedwa kale MXenes Nb2CTx ndi Nb4C3TX38,39,40,41 motsatira.Zotsatira za XRD zimasonyezanso kukhalapo kwa zotsalira za ML zotsalira ndi magawo MAX, koma makamaka XRD machitidwe ogwirizana ndi SL Nb4C3Tx (Mkuyu 2e2).Kukhalapo kwa tinthu tating'ono ta gawo la MAX kumatha kufotokozera nsonga yamphamvu ya MAX poyerekeza ndi zigawo za Nb4C3Tx zosanjikizana mwachisawawa.
Kafukufuku wowonjezereka ayang'ana pa ma microalgae obiriwira amtundu wa R. subcapitata.Tidasankha ma microalgae chifukwa ndiwopanga ofunikira omwe amakhudzidwa ndi chakudya chachikulu cha webs42.Iwonso ndi chimodzi mwazizindikiro zabwino kwambiri za kawopsedwe chifukwa chotha kuchotsa zinthu zapoizoni zomwe zimatengedwa kupita kumagulu apamwamba a chain43.Kuonjezera apo, kafukufuku wa R. subcapitata akhoza kuwunikira za poizoni wa SL Nb-MXenes ku tizilombo tating'onoting'ono tamadzi.Kuti awonetsere izi, ofufuzawo adaganiza kuti kachilomboka kalikonse kamakhala ndi chidwi chosiyana ndi zinthu zapoizoni zomwe zimapezeka m'chilengedwe.Kwa zamoyo zambiri, kuchuluka kwa zinthu zotsika sikumakhudza kukula kwawo, pomwe kuchuluka kwambiri kuposa malire kumatha kuwalepheretsa kapena kufa.Chifukwa chake, pamaphunziro athu okhudzana ndi kuyanjana kwapakati pakati pa ma microalgae ndi MXenes ndi kuchira kogwirizana, tinaganiza zoyesa kuchuluka kopanda vuto komanso koopsa kwa Nb-MXenes.Kuti tichite zimenezi, ife anayesedwa woipa wa 0 (monga buku), 0.01, 0.1 ndi 10 mg l-1 MXene ndi kuwonjezera kachilombo microalgae ndi woipa kwambiri wa MXene (100 mg l-1 MXene), amene angakhale kwambiri ndi wakupha..kwa chilengedwe chilichonse chachilengedwe.
Zotsatira za SL Nb-MXenes pa microalgae zikuwonetsedwa mu Chithunzi 3, chofotokozedwa ngati chiwerengero cha kukula kwa kukula (+) kapena kuletsa (-) kuyeza kwa 0 mg l-1 zitsanzo.Poyerekeza, gawo la Nb-MAX ndi ML Nb-MXenes adayesedwanso ndipo zotsatira zikuwonetsedwa mu SI (onani Mkuyu S3).Zotsatira zomwe zinapezedwa zimatsimikizira kuti SL Nb-MXenes pafupifupi alibe poizoni m'magulu otsika kwambiri kuchokera ku 0.01 mpaka 10 mg / l, monga momwe tawonetsera mkuyu 3a, b.Pankhani ya Nb2CTx, sitinawone kupitirira 5% ecotoxicity mumtundu womwe watchulidwa.
Kukondoweza (+) kapena kulepheretsa (-) kukula kwa microalgae pamaso pa SL (a) Nb2CTx ndi (b) Nb4C3TX MXene.Maola 24, 48 ndi 72 a kuyanjana kwa MXene-microalgae adawunikidwa. Deta yofunikira (t-test, p <0.05) idalembedwa ndi asterisk (*). Deta yofunikira (t-test, p <0.05) idalembedwa ndi asterisk (*). Значимые данные (t-критерий, p <0,05) отмечены звездочкой (*). Deta yofunikira (t-test, p <0.05) imalembedwa ndi 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 (*). Deta yofunika (t-test, p <0.05) imalembedwa ndi asterisk (*).Mivi yofiira imasonyeza kuthetsedwa kwa kukondoweza koletsa.
Kumbali inayi, kutsika kochepa kwa Nb4C3TX kunakhala koopsa pang'ono, koma osapitirira 7%.Monga tikuyembekezeredwa, tidawona kuti MXenes anali ndi kawopsedwe wamkulu komanso zoletsa kukula kwa microalgae pa 100mg L-1.Chosangalatsa ndichakuti palibe zida zomwe zidawonetsa momwe zimakhalira komanso kudalira nthawi kwapoizoni/poizoni poyerekeza ndi zitsanzo za MAX kapena ML (onani SI kuti mumve zambiri).Ngakhale kuti gawo la MAX (onani Mkuyu. S3) kawopsedwe kanafika pafupifupi 15-25% ndikuwonjezeka pakapita nthawi, kusinthaku kunawonedwa kwa SL Nb2CTx ndi Nb4C3TX MXene.Kuletsa kukula kwa microalgae kunachepa pakapita nthawi.Idafika pafupifupi 17% pambuyo pa maola 24 ndipo idatsikira pansi pa 5% pambuyo pa maola 72 (mkuyu 3a, b, motsatira).
Chofunika kwambiri, kwa SL Nb4C3TX, kulepheretsa kukula kwa microalgae kunafika pafupifupi 27% pambuyo pa maola 24, koma pambuyo pa maola 72 kunatsika pafupifupi 1%.Chifukwa chake, tidatchula zotsatira zowoneka ngati zoletsa kukondoweza, ndipo zotsatira zake zinali zamphamvu kwa SL Nb4C3TX MXene.Kukondoweza kwa kukula kwa microalgae kunadziwika kale ndi Nb4C3TX (kuyanjana pa 10 mg L-1 kwa 24 h) poyerekeza ndi SL Nb2CTx MXene.Kuletsa-kukondoweza reversal zotsatira anasonyezedwanso bwino biomass kuwirikiza kawiri mlingo pamapindikira (onani Mkuyu. S4 mwatsatanetsatane).Pakadali pano, ecotoxicity yokha ya Ti3C2TX MXene yaphunziridwa m'njira zosiyanasiyana.Siwowopsa kwa mbidzi embryos44 koma ndi ecotoxic ku zomera zazing'ono za Desmodesmus quadricauda ndi Sorghum saccharatum45.Zitsanzo zina za zotsatira zapadera zikuphatikizapo kuopsa kwa ma cell a khansa kusiyana ndi ma cell46,47.Zitha kuganiziridwa kuti miyeso yoyeserera ingakhudze kusintha kwa kukula kwa microalgae komwe kumawonedwa pamaso pa Nb-MXenes.Mwachitsanzo, pH ya pafupifupi 8 mu chloroplast stroma ndi yabwino pakugwira ntchito bwino kwa enzyme ya RuBisCO.Chifukwa chake, kusintha kwa pH kumakhudza kwambiri kuchuluka kwa photosynthesis48,49.Komabe, sitinawone kusintha kwakukulu kwa pH panthawi yoyesera (onani SI, Fig. S5 kuti mudziwe zambiri).Kawirikawiri, zikhalidwe za microalgae ndi Nb-MXenes zimachepetsa pang'ono pH ya yankho pakapita nthawi.Komabe, kuchepa uku kunali kofanana ndi kusintha kwa pH ya sing'anga yoyera.Kuonjezera apo, mitundu yosiyanasiyana yomwe inapezeka inali yofanana ndi yomwe imayeza chikhalidwe choyera cha microalgae (chitsanzo chowongolera).Chifukwa chake, timapeza kuti photosynthesis simakhudzidwa ndi kusintha kwa pH pakapita nthawi.
Kuphatikiza apo, ma MXenes opangidwa amakhala ndi mathero apamwamba (otchedwa Tx).Awa ndi magulu ogwira ntchito -O, -F ndi -OH.Komabe, chemistry ya pamwamba imagwirizana mwachindunji ndi njira yophatikizira.Maguluwa amadziwika kuti amagawidwa mwachisawawa pamtunda, zomwe zimapangitsa kuti zikhale zovuta kufotokoza zotsatira zake pa katundu wa MXene50.Tinganene kuti Tx ikhoza kukhala mphamvu yothandizira kuti niobium ikhale yowala.Magulu ogwira ntchito apamtunda amaperekadi malo angapo okhazikika a ma photocatalyst awo apansi kuti apange ma heterojunctions51.Komabe, kukula kwa sing'anga sikunapereke photocatalyst yogwira mtima (zambiri zapakatikati zolembedwa zitha kupezeka mu SI Table S6).Kuonjezera apo, kusinthidwa kulikonse padziko lapansi kulinso kofunika kwambiri, monga momwe biological ntchito ya MXenes ingasinthidwe chifukwa cha kusanjikiza pambuyo pokonza, makutidwe ndi okosijeni, kusintha kwa mankhwala pamwamba pa organic ndi inorganic compounds52,53,54,55,56 kapena pamwamba pa engineering engineering38.Chifukwa chake, kuyesa ngati niobium oxide ili ndi chochita ndi kusakhazikika kwazinthu pakati, tidachita maphunziro a zeta (ζ) kuthekera kwapakatikati mwa kukula kwa microalgae ndi madzi a deionized (poyerekeza).Zotsatira zathu zikuwonetsa kuti SL Nb-MXenes ndi yokhazikika (onani SI Fig. S6 ya MAX ndi ML zotsatira).Kuthekera kwa zeta kwa SL MXenes kuli pafupifupi -10 mV.Pankhani ya SR Nb2CTx, mtengo wa ζ ndi woipa kwambiri kuposa wa Nb4C3Tx.Kusintha koteroko kwa mtengo wa ζ kungasonyeze kuti pamwamba pa ma nanoflakes a MXene omwe amanyamulidwa molakwika amayamwa ma ion opangidwa bwino kuchokera ku chikhalidwe cha chikhalidwe.Kuyeza kwakanthawi kwa zeta zomwe zingatheke komanso kusinthika kwa Nb-MXenes mu chikhalidwe cha chikhalidwe (onani Zithunzi S7 ndi S8 mu SI kuti mudziwe zambiri) zikuwoneka kuti zikugwirizana ndi malingaliro athu.
Komabe, ma Nb-MXene SL onse adawonetsa zosintha zochepa kuchokera ku ziro.Izi zikuwonetseratu kukhazikika kwawo mu kukula kwa microalgae.Kuonjezera apo, tinayesa ngati kupezeka kwa microalgae yathu yobiriwira kungakhudze kukhazikika kwa Nb-MXenes pakati.Zotsatira za zeta zomwe zingatheke ndi ma conductivity a MXenes pambuyo poyanjana ndi microalgae muzofalitsa zopatsa thanzi ndi chikhalidwe pakapita nthawi zingapezeke mu SI (Zithunzi S9 ndi S10).Chochititsa chidwi, tinawona kuti kukhalapo kwa microalgae kunkawoneka kuti kukhazikitsira kubalalitsidwa kwa onse a MXenes.Pankhani ya Nb2CTx SL, kuthekera kwa zeta kudatsika pang'ono pakapita nthawi kupita kuzinthu zoyipa (-15.8 motsutsana ndi -19.1 mV pambuyo pa 72 h of incubation).Mphamvu ya zeta ya SL Nb4C3TX inakula pang'ono, koma pambuyo pa 72 h idawonetsabe kukhazikika kwapamwamba kuposa nanoflakes popanda kukhalapo kwa microalgae (-18.1 vs. -9.1 mV).
Tinapezanso ma conductivity otsika a njira za Nb-MXene zomwe zimapangidwira pamaso pa microalgae, zomwe zimasonyeza kuchepa kwa ayoni m'kati mwazakudya.Makamaka, kusakhazikika kwa ma MXenes m'madzi kumachitika makamaka chifukwa cha okosijeni pamwamba57.Chifukwa chake, timakayikira kuti ma microalgae obiriwira mwanjira ina adachotsa ma oxide omwe adapangidwa pamwamba pa Nb-MXene ndipo amalepheretsa kupezeka kwawo (makutidwe ndi okosijeni a MXene).Izi zitha kuwoneka powerenga mitundu ya zinthu zomwe zimatengedwa ndi ma microalgae.
Ngakhale kuti maphunziro athu a zachilengedwe asonyeza kuti ma microalgae amatha kuthana ndi poizoni wa Nb-MXenes pakapita nthawi komanso kulepheretsa kwachilendo kwa kukula kolimbikitsidwa, cholinga cha phunziro lathu chinali kufufuza njira zomwe zingatheke.Zamoyo monga algae zikakumana ndi zinthu kapena zinthu zomwe sizikudziwika bwino ndi chilengedwe chawo, zimatha kuchita mwanjira zosiyanasiyana58,59.Pakalibe ma oxide achitsulo oopsa, ma microalgae amatha kudzidyetsa okha, kuwalola kuti akule mosalekeza60.Mukameza zinthu zapoizoni, njira zodzitetezera zitha kuyambitsidwa, monga kusintha mawonekedwe kapena mawonekedwe.Kuthekera kwa kuyamwa kuyeneranso kuganiziridwa58,59.Mwachidziwitso, chizindikiro chilichonse cha njira yodzitetezera ndi chizindikiro chodziwikiratu cha poizoni wamagulu oyesera.Choncho, mu ntchito yathu yowonjezera, tinafufuza momwe tingagwiritsire ntchito pamwamba pa SL Nb-MXene nanoflakes ndi microalgae ndi SEM komanso kuyamwa kwa Nb-based MXene ndi X-ray fluorescence spectroscopy (XRF).Zindikirani kuti kusanthula kwa SEM ndi XRF kunangochitika pamalo okwera kwambiri a MXene kuthana ndi zovuta zapoizoni.
Zotsatira za SEM zikuwonetsedwa mu Fig.4.Maselo a microalgae osasamalidwa (onani mkuyu 4a, chitsanzo chofotokozera) akuwonetseratu mawonekedwe a R. subcapitata morphology ndi mawonekedwe a selo ngati croissant.Maselo amawoneka ophwanyika komanso osalongosoka.Ma cell ena amtundu wa microalgae adalumikizana ndikulumikizana wina ndi mzake, koma izi mwina zidachitika chifukwa cha kukonzekera kwachitsanzo.Kawirikawiri, maselo oyera a microalgae anali ndi malo osalala ndipo sanasonyeze kusintha kwa morphological.
Zithunzi za SEM zomwe zikuwonetsa kuyanjana kwapakati pakati pa green algae ndi MXene nanosheets pambuyo pa maola 72 akulumikizana kwambiri (100 mg L-1).(a) Ma microalgae obiriwira osagwiritsidwa ntchito atagwirizana ndi SL (b) Nb2CTx ndi (c) Nb4C3TX MXenes.Dziwani kuti ma nanoflakes a Nb-MXene amalembedwa ndi mivi yofiira.Poyerekeza, zithunzi zochokera ku microscope ya kuwala zimawonjezeredwa.
Mosiyana ndi zimenezi, maselo a microalgae omwe amagulitsidwa ndi SL Nb-MXene nanoflakes anawonongeka (onani mkuyu 4b, c, mivi yofiira).Pankhani ya Nb2CTx MXene (mkuyu. 4b), microalgae amakonda kukula ndi Ufumuyo awiri azithunzi nanoscales, amene angasinthe morphology awo.Makamaka, tidawonanso zosinthazi pansi pa microscope (onani Chithunzi cha SI S11 kuti mumve zambiri).Kusintha kwa morphological uku kuli ndi maziko omveka mu physiology ya microalgae ndi kuthekera kwawo kudziteteza posintha ma cell morphology, monga kuchulukitsa cell volume61.Chifukwa chake, ndikofunikira kuyang'ana kuchuluka kwa ma cell algae omwe amalumikizana ndi Nb-MXenes.Kafukufuku wa SEM adawonetsa kuti pafupifupi 52% ya ma cell algae adakumana ndi Nb-MXenes, pomwe 48% ya ma cell algae amapewa kukhudzana.Kwa SL Nb4C3Tx MXene, ma microalgae amayesa kupewa kukhudzana ndi MXene, potero amalowa ndikukula kuchokera ku nanoscales yamitundu iwiri (mkuyu 4c).Komabe, sitinawone kulowa kwa nanoscales m'maselo a microalgae ndi kuwonongeka kwawo.
Kudziteteza kumakhalanso kutengera nthawi yoyankha kutsekeka kwa photosynthesis chifukwa cha kutsatsa kwa tinthu tating'ono pa cell komanso zomwe zimatchedwa shading (shading) effect62.Zikuwonekeratu kuti chinthu chilichonse (mwachitsanzo, Nb-MXene nanoflakes) chomwe chili pakati pa microalgae ndi gwero la kuwala kumachepetsa kuchuluka kwa kuwala komwe kumatengedwa ndi chloroplasts.Komabe, sitikukayikira kuti izi zimakhudza kwambiri zotsatira zomwe zapezedwa.Monga momwe tawonera paziwonetsero zathu zazing'ono, ma nanoflakes a 2D sanali atakulungidwa kwathunthu kapena kumamatira pamwamba pa microalgae, ngakhale pamene maselo a microalgae adalumikizana ndi Nb-MXenes.M'malo mwake, ma nanoflakes adakhala olunjika ku ma cell algae osaphimba pamwamba.Seti yotereyi ya nanoflakes/microalgae silingathe kuchepetsa kwambiri kuchuluka kwa kuwala komwe kumatengedwa ndi ma cell algae.Komanso, maphunziro ena awonetsanso kusintha kwa kuyamwa kwa kuwala ndi zamoyo za photosynthetic pamaso pa nanomaterials awiri-dimensional63,64,65,66.
Popeza zithunzi za SEM sizikanatha kutsimikizira mwachindunji kutengedwa kwa niobium ndi ma cell algae, kafukufuku wathu wopitilira adatembenukira ku X-ray fluorescence (XRF) ndi X-ray photoelectron spectroscopy (XPS) kusanthula kumveketsa bwino nkhaniyi.Choncho, ife anayerekezera mphamvu ya Nb nsonga za umboni microalgae zitsanzo kuti sanagwirizane ndi MXenes, MXene nanoflakes detached kuchokera pamwamba maselo a microalgae, ndi maselo microalgal pambuyo kuchotsa Ufumuyo MXenes.Ndikoyenera kudziwa kuti ngati palibe kutengeka kwa Nb, mtengo wa Nb wopezedwa ndi maselo a microalgae uyenera kukhala zero pambuyo pochotsa nanoscales.Chifukwa chake, ngati kutengeka kwa Nb kumachitika, zotsatira za XRF ndi XPS ziyenera kuwonetsa nsonga ya Nb yomveka.
Pankhani ya XRF spectra, zitsanzo za microalgae zimasonyeza Nb nsonga za SL Nb2CTx ndi Nb4C3Tx MXene pambuyo poyanjana ndi SL Nb2CTx ndi Nb4C3Tx MXene (onani mkuyu 5a, onaninso kuti zotsatira za MAX ndi ML MXenes zikuwonetsedwa mu SI, Figs 172).Chochititsa chidwi n'chakuti, mphamvu ya Nb yapamwamba imakhala yofanana muzochitika zonsezi (mipiringidzo yofiira mu Fig. 5a).Izi zinasonyeza kuti algae sakanatha kuyamwa kwambiri Nb, ndipo mphamvu yaikulu ya Nb kudzikundikira inapezeka m'maselo, ngakhale kuti kawiri kawiri Nb4C3Tx MXene inagwirizanitsidwa ndi maselo a microalgae (mipiringidzo ya buluu mu Fig. 5a).Makamaka, kuthekera kwa microalgae kuyamwa zitsulo kumadalira kuchuluka kwa ma oxides achitsulo m'chilengedwe67,68.Shamshada et al.67 adapeza kuti kuyamwa kwa algae m'madzi amchere kumachepa ndi kuchuluka kwa pH.Raize et al.68 adanenanso kuti kuthekera kwa m'nyanja zam'madzi kutengera zitsulo kunali pafupifupi 25% kuposa Pb2 + kuposa Ni2 +.
(a) Zotsatira za XRF za basal Nb kutengedwa ndi maselo obiriwira a microalgae omwe amaikidwa pamtundu wambiri wa SL Nb-MXenes (100 mg L-1) kwa maola 72.Zotsatira zikuwonetsa kukhalapo kwa α m'maselo oyera amtundu wa microalgae (chitsanzo chowongolera, mizati ya imvi), ma nanoflakes a 2D olekanitsidwa ndi maselo amtundu wa buluu (mizere ya buluu), ndi ma cell algae atapatukana ndi 2D nanoflakes kuchokera pamwamba (mizere yofiira).Kuchuluka kwa elemental Nb, (b) peresenti ya mankhwala opangidwa ndi microalgae organic components (C = O ndi CHx / C-O) ndi Nb oxides omwe amapezeka m'maselo a microalgae atatha kupangidwa ndi SL Nb-MXenes, (c-e) Kukonzekera nsonga yamtundu wa XPS SL Nb2CTx spectra yamkati ndi MXx Nb4T SL ndi (fh4C)
Chifukwa chake, tinkayembekezera kuti Nb ikhoza kutengedwa ndi ma cell a algal mu mawonekedwe a oxides.Kuti tiyese izi, tinachita maphunziro a XPS pa MXenes Nb2CTx ndi Nb4C3TX ndi maselo a algae.Zotsatira za kuyanjana kwa microalgae ndi Nb-MXenes ndi MXenes olekanitsidwa ndi maselo a algae akuwonetsedwa muzithunzi.5b .Monga kuyembekezera, tinazindikira Nb 3d nsonga mu zitsanzo microalgae pambuyo kuchotsa MXene pamwamba pa microalgae.Kutsimikiza kwachulukidwe kwa C = O, CHx / CO, ndi Nb oxides kunawerengedwa kutengera Nb 3d, O 1s, ndi C 1s spectra yomwe inapezedwa ndi Nb2CTx SL (Mkuyu 5c-e) ndi Nb4C3Tx SL (Mkuyu 5c-e).) zotengedwa kuchokera ku incubated microalgae.Chithunzi 5f–h) Mxenes.Table S1-3 ikuwonetsa tsatanetsatane wa magawo apamwamba komanso chemistry yonse yomwe imachokera pakukwanira.Ndizodabwitsa kuti zigawo za Nb 3d za Nb2CTx SL ndi Nb4C3Tx SL (mkuyu 5c, f) zimagwirizana ndi gawo limodzi la Nb2O5.Pano, sitinapeze nsonga zokhudzana ndi MXene pamasewero, zomwe zimasonyeza kuti maselo a microalgae amangotenga mawonekedwe a oxide a Nb.Kuphatikiza apo, tidayerekeza mawonekedwe a C 1 ndi C-C, CHx/C-O, C=O, ndi -COOH.Tidagawira nsonga za CHx/C–O ndi C=O pakuthandizira kwachilengedwe kwa ma cell algae.Zigawo za organic izi zimakhala ndi 36% ndi 41% ya nsonga za C 1s mu Nb2CTx SL ndi Nb4C3TX SL, motsatira.Kenaka tinayika mawonekedwe a O 1s a SL Nb2CTx ndi SL Nb4C3TX ndi Nb2O5, zigawo za organic za microalgae (CHx/CO), ndi madzi otsekemera pamwamba.
Pomaliza, zotsatira za XPS zikuwonetsa bwino mawonekedwe a Nb, osati kupezeka kwake.Malingana ndi malo a chizindikiro cha Nb 3d ndi zotsatira za deconvolution, timatsimikizira kuti Nb imatengedwa ngati mawonekedwe a oxides osati ions kapena MXene yokha.Kuonjezera apo, zotsatira za XPS zimasonyeza kuti maselo a microalgae ali ndi mphamvu zambiri zotengera Nb oxides kuchokera ku SL Nb2CTx poyerekeza ndi SL Nb4C3TX MXene.
Ngakhale zotsatira zathu zotengera Nb zimakhala zochititsa chidwi ndipo zimatilola kuzindikira kuwonongeka kwa MXene, palibe njira yomwe ilipo kuti iwonetsere kusintha kwa morphological ku 2D nanoflakes.Choncho, tinaganizanso kupanga njira yoyenera yomwe ingayankhe mwachindunji kusintha kulikonse komwe kumachitika mu 2D Nb-MXene nanoflakes ndi maselo a microalgae.Ndikofunika kuzindikira kuti tikuganiza kuti ngati mitundu yolumikizana ikukumana ndi kusintha kulikonse, kuwonongeka kapena kuwonongeka, izi ziyenera kudziwonetsera mwamsanga monga kusintha kwa mawonekedwe a mawonekedwe, monga kukula kwa dera lofanana lozungulira, kuzungulira, Feret wide, kapena Feret kutalika.Popeza magawowa ndi oyenera kufotokozera tinthu tating'onoting'ono kapena tinthu tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono, kutsatira kwawo ndi kusanthula kwa mawonekedwe a tinthu kudzatipatsa chidziwitso chofunikira chokhudza kusintha kwa morphological kwa SL Nb-MXene nanoflakes pakuchepetsa.
Zotsatira zomwe zapezedwa zikuwonetsedwa mu Chithunzi 6. Poyerekeza, tinayesanso gawo loyambirira la MAX ndi ML-MXenes (onani SI Figures S18 ndi S19).Kusanthula kwamphamvu kwa mawonekedwe a tinthu kunawonetsa kuti magawo onse a mawonekedwe a Nb-MXene SLs awiri adasintha kwambiri pambuyo polumikizana ndi ma microalgae.Monga momwe zasonyezedwera ndi gawo lofanana lozungulira la m'mimba mwake (mkuyu 6a, b), kuchepetsedwa kwapamwamba kwambiri kwa kachigawo kakang'ono ka nanoflakes kumasonyeza kuti amawola kukhala tizidutswa tating'ono.Pa mkuyu.6c, d ikuwonetsa kuchepa kwa nsonga zomwe zimagwirizanitsidwa ndi kukula kwa ma flakes (kutalika kwa nanoflakes), kusonyeza kusintha kwa 2D nanoflakes kukhala mawonekedwe a tinthu tating'ono.Chithunzi 6e-h kusonyeza m'lifupi ndi kutalika kwa Feret, motero.M'lifupi mwake ndi kutalika kwake ndizomwe zimayenderana, choncho ziyenera kuganiziridwa pamodzi.Pambuyo pa kukulitsidwa kwa 2D Nb-MXene nanoflakes pamaso pa microalgae, nsonga zawo za mgwirizano wa Feret zinasintha ndipo mphamvu yawo inachepa.Kutengera zotsatira izi osakaniza morphology, XRF ndi XPS, tinaona kuti kusintha anaona kwambiri zokhudzana makutidwe ndi okosijeni monga okosijeni MXenes kukhala makwinya ndi kusweka mu zidutswa ndi ozungulira okusayidi particles69,70.
Kusanthula kwa kusintha kwa MXene pambuyo polumikizana ndi green microalgae.Kusanthula kwamphamvu kwa tinthu tating'onoting'ono kumatengera magawo monga (a, b) m'mimba mwake wa malo ozungulira ofanana, (c, d) ozungulira, (e, f) M'lifupi mwake ndi (g, h) kutalika kwa Feret.Kuti izi zitheke, zitsanzo ziwiri za microalgae zinawunikidwa pamodzi ndi SL Nb2CTx yoyamba ndi SL Nb4C3Tx MXenes, SL Nb2CTx ndi SL Nb4C3Tx MXenes, microalgae yowonongeka, ndi mankhwala a microalgae SL Nb2CTx ndi SL Nb4C3Tx MXenes.Mivi yofiira ikuwonetsa kusintha kwa magawo a mawonekedwe a nanoflakes omwe amaphunzira amitundu iwiri.
Popeza kusanthula kwa mawonekedwe ndikodalirika kwambiri, kumatha kuwululanso kusintha kwa ma morphological m'ma cell algae.Choncho, ife kusanthula ofanana zozungulira m'mimba mwake, roundness, ndi Feret m'lifupi/utali wa maselo oyera microalgae ndi maselo pambuyo kucheza ndi 2D Nb nanoflakes.Pa mkuyu.6a-h amasonyeza kusintha kwa mawonekedwe a maselo a algae, monga momwe zimasonyezedwera ndi kuchepa kwapamwamba kwambiri komanso kusintha kwa maxima kupita kuzinthu zapamwamba.Makamaka, maselo kuzungulira magawo anasonyeza kuchepa kwa maselo elongated ndi kuwonjezeka ozungulira maselo (mkuyu. 6a, b).Kuonjezera apo, Feret cell m'lifupi inakula ndi micrometers angapo pambuyo kugwirizana ndi SL Nb2CTx MXene (mkuyu. 6e) poyerekeza SL Nb4C3TX MXene (mkuyu. 6f).Tikukayikira kuti izi zitha kukhala chifukwa cha kutengeka mwamphamvu kwa Nb oxides ndi ma microalgae polumikizana ndi Nb2CTx SR.Kumangika pang'ono kwa ma flakes a Nb pamwamba pawo kumatha kupangitsa kukula kwa ma cell ndi mawonekedwe ochepa a shading.
Kuwona kwathu pakusintha kwa magawo a mawonekedwe ndi kukula kwa microalgae kumakwaniritsa maphunziro ena.Ma microalgae obiriwira amatha kusintha mawonekedwe awo poyankha kupsinjika kwa chilengedwe posintha kukula kwa cell, mawonekedwe kapena metabolism61.Mwachitsanzo, kusintha kukula kwa maselo kumathandizira kuyamwa kwa michere71.Maselo ang'onoang'ono a algae amawonetsa kuchepa kwa michere komanso kuchepa kwa kukula.Mosiyana ndi zimenezi, maselo akuluakulu amakonda kudya zakudya zambiri, zomwe zimayikidwa intracellularly72,73.Machado ndi Soares adapeza kuti fungicide triclosan imatha kukulitsa kukula kwa maselo.Anapezanso kusintha kwakukulu mu mawonekedwe a algae74.Kuonjezera apo, Yin et al.9 adawonetsanso kusintha kwa morphological mu algae pambuyo pokhudzana ndi kuchepa kwa graphene oxide nanocomposites.Choncho, zikuwonekeratu kuti kusintha kwa kukula / mawonekedwe a microalgae amayamba chifukwa cha kukhalapo kwa MXene.Popeza kusintha kumeneku kwa kukula ndi mawonekedwe kumasonyeza kusintha kwa zakudya zowonjezera, timakhulupirira kuti kusanthula kukula ndi mawonekedwe a mawonekedwe pakapita nthawi kungasonyeze kutengeka kwa niobium oxide ndi microalgae pamaso pa Nb-MXenes.
Komanso, ma MXenes amatha kukhala oxidized pamaso pa algae.Dalai et al.75 adawona kuti morphology ya algae yobiriwira yomwe imapezeka ku nano-TiO2 ndi Al2O376 sinali yunifolomu.Ngakhale kuti zomwe taziwona ndizofanana ndi zomwe taphunzira pano, zimangogwirizana ndi kafukufuku wa zotsatira za bioremediation ponena za zinthu zowonongeka za MXene pamaso pa 2D nanoflakes osati nanoparticles.Popeza MXenes akhoza kuwononga zitsulo zazitsulo, 31,32,77,78 ndizomveka kuganiza kuti Nb nanoflakes yathu imatha kupanga Nb oxides pambuyo poyanjana ndi maselo a microalgae.
Kuti tifotokoze kuchepetsedwa kwa 2D-Nb nanoflakes kudzera mu njira yowonongeka yochokera ku ndondomeko ya okosijeni, tinachita maphunziro pogwiritsa ntchito ma electron microscopy (HRTEM) (Mkuyu 7a, b) ndi X-ray photoelectron spectroscopy (XPS) (Mkuyu 7).7c-i ndi matebulo S4-5).Njira zonse ziwirizi ndizoyenera kuphunzira makutidwe ndi okosijeni a zida za 2D ndikuthandizirana.HRTEM amatha kusanthula kuwonongeka kwa magawo awiri azithunzi zosanjikiza ndi mawonekedwe a zitsulo za oxide nanoparticles, pamene XPS imakhudzidwa ndi zomangira zapansi.Pachifukwa ichi, tinayesa 2D Nb-MXene nanoflakes yotengedwa kuchokera ku microalgae cell dispersions, ndiko kuti, mawonekedwe awo atatha kugwirizana ndi maselo a microalgae (onani mkuyu 7).
Zithunzi za HRTEM zomwe zikuwonetsa morphology ya oxidized (a) SL Nb2CTx ndi (b) SL Nb4C3Tx MXenes, zotsatira za kusanthula kwa XPS zikuwonetsa (c) kupangidwa kwa zinthu za oxide pambuyo pochepetsa, (d-f) kufanana kwakukulu kwa zigawo za XPS spectra ya SL Nb2CTx ndi (g- i) yobiriwira ya Nb4Ced Nb4Ce.
Maphunziro a HRTEM adatsimikizira makutidwe ndi okosijeni amitundu iwiri ya Nb-MXene nanoflakes.Ngakhale kuti ma nanoflakes anasunga mawonekedwe awo amitundu iwiri mpaka kufika pamlingo wina, okosijeni kunachititsa kuti ma nanoparticles ambiri awoneke pamwamba pa MXene nanoflakes (onani mkuyu 7a, b).Kusanthula kwa XPS kwa c Nb 3d ndi O 1s chizindikiro kunasonyeza kuti Nb oxides inapangidwa muzochitika zonsezi.Monga momwe tawonetsera pa Chithunzi 7c, 2D MXene Nb2CTx ndi Nb4C3TX ali ndi zizindikiro za Nb 3d zosonyeza kukhalapo kwa NbO ndi Nb2O5 oxides, pamene zizindikiro za O 1s zimasonyeza chiwerengero cha O-Nb chogwirizana ndi magwiridwe antchito a 2D nanoflake pamwamba.Tawona kuti zopereka za Nb oxide ndizopambana poyerekeza ndi Nb-C ndi Nb3 + -O.
Pa mkuyu.Zithunzi 7g-ndikuwonetsa mawonekedwe a XPS a Nb 3d, C 1s, ndi O 1s SL Nb2CTx (onani Zithunzi 7d-f) ndi SL Nb4C3TX MXene olekanitsidwa ndi maselo a microalgae.Tsatanetsatane wa magawo apamwamba a Nb-MXenes amaperekedwa mu Matebulo S4-5, motsatana.Tidasanthula kaye kapangidwe ka Nb 3d.Mosiyana ndi Nb yotengedwa ndi maselo a microalgae, mu MXene olekanitsidwa ndi maselo a microalgae, kupatulapo Nb2O5, zigawo zina zinapezeka.Mu Nb2CTx SL, tinawona zopereka za Nb3 + -O mu kuchuluka kwa 15%, pamene zina zonse za Nb 3d zinkayang'aniridwa ndi Nb2O5 (85%).Kuphatikiza apo, chitsanzo cha SL Nb4C3TX chili ndi zigawo za Nb-C (9%) ndi Nb2O5 (91%).Apa Nb-C imachokera ku zigawo ziwiri zamkati za atomiki za carbide yachitsulo mu Nb4C3Tx SR.Kenako timajambula mawonekedwe a C 1s ku zigawo zinayi zosiyana, monga momwe tinachitira mu zitsanzo zamkati.Monga zikuyembekezeredwa, mawonekedwe a C 1s amatsogoleredwa ndi graphic carbon, kutsatiridwa ndi zopereka zochokera ku organic particles (CHx / CO ndi C = O) kuchokera ku maselo a microalgae.Kuphatikiza apo, mu mawonekedwe a O 1s, tidawona zopereka zamitundu yama cell algae, niobium oxide, ndi madzi adsorbed.
Kuonjezera apo, tinafufuza ngati Nb-MXenes cleavage ikugwirizana ndi kukhalapo kwa mitundu yowonjezereka ya okosijeni (ROS) m'kati mwazomera ndi / kapena ma cell algae.Kuti izi zitheke, tinayesa milingo ya singlet oxygen (1O2) mu chikhalidwe chapakati ndi intracellular glutathione, thiol yomwe imakhala ngati antioxidant mu microalgae.Zotsatira zikuwonetsedwa mu SI (Zithunzi S20 ndi S21).Zikhalidwe zomwe zili ndi SL Nb2CTx ndi Nb4C3TX MXenes zinkadziwika ndi kuchepa kwa 1O2 (onani Chithunzi S20).Pankhani ya SL Nb2CTx, MXene 1O2 imachepetsedwa mpaka 83%.Kwa zikhalidwe za microalgae pogwiritsa ntchito SL, Nb4C3TX 1O2 idatsika kwambiri, mpaka 73%.Chochititsa chidwi n'chakuti, kusintha kwa 1O2 kunawonetsa zomwezo monga momwe zimakhalira kale zolepheretsa-stimulatory zotsatira (onani mkuyu 3).Tinganene kuti makulitsidwe mu kuwala kowala akhoza kusintha photooxidation.Komabe, zotsatira za kusanthula ulamuliro anasonyeza pafupifupi zonse milingo 1O2 pa kuyesera (mkuyu. S22).Pankhani ya ma intracellular ROS, tidawonanso kutsika komweko (onani Chithunzi S21).Poyambirira, milingo ya ROS m'maselo ang'onoang'ono a algae otukuka pamaso pa Nb2CTx ndi Nb4C3Tx SLs idaposa milingo yomwe imapezeka m'zikhalidwe zoyera za microalgae.Komabe, pamapeto pake, zinawoneka kuti microalgae inasinthidwa kukhalapo kwa onse a Nb-MXenes, monga momwe ma ROS amatsikira ku 85% ndi 91% ya miyeso yomwe imayesedwa mu zikhalidwe zoyera za microalgae zojambulidwa ndi SL Nb2CTx ndi Nb4C3TX, motero.Izi zikhoza kusonyeza kuti ma microalgae amamva bwino pakapita nthawi pamaso pa Nb-MXene kusiyana ndi mchere wokha.
Microalgae ndi gulu losiyanasiyana la zamoyo za photosynthetic.Pa photosynthesis, amasintha mpweya woipa wa carbon dioxide (CO2) kukhala carbon carbon.Zopangidwa ndi photosynthesis ndi glucose ndi oxygen79.Timakayikira kuti mpweya wopangidwa motero umagwira ntchito yofunika kwambiri pakutulutsa kwa Nb-MXenes.Kufotokozera kumodzi kotheka kwa izi ndikuti kusiyanitsa kwa aeration parameter kumapangidwa pazovuta zochepa komanso zochepa za mpweya kunja ndi mkati mwa Nb-MXene nanoflakes.Izi zikutanthauza kuti kulikonse komwe kuli madera osiyanasiyana a mpweya wa okosijeni, malo omwe ali otsika kwambiri adzapanga anode 80, 81, 82. Apa, microalgae imathandizira kuti pakhale maselo osakanikirana aerated pamwamba pa MXene flakes, yomwe imatulutsa mpweya chifukwa cha photosynthetic.Zotsatira zake, zinthu za biocorrosion (panthawiyi, niobium oxides) zimapangidwa.Chinanso ndikuti ma microalgae amatha kupanga ma organic acid omwe amatulutsidwa m'madzi83,84.Chifukwa chake, malo aukali amapangidwa, potero amasintha Nb-MXenes.Kuonjezera apo, ma microalgae amatha kusintha pH ya chilengedwe kukhala yamchere chifukwa cha kuyamwa kwa carbon dioxide, komwe kungayambitsenso corrosion79.
Chofunika koposa, chithunzi chamdima / chopepuka chomwe chimagwiritsidwa ntchito mu phunziro lathu ndichofunikira kuti timvetsetse zotsatira zomwe zapezedwa.Mbaliyi ikufotokozedwa mwatsatanetsatane mu Djemai-Zoghlache et al.85 Mwadala adagwiritsa ntchito chithunzi cha ola la 12/12 kuwonetsa biocorrosion yolumikizidwa ndi biofouling ndi red microalgae Porphyridium purpureum.Amasonyeza kuti photoperiod ikugwirizana ndi kusinthika kwa kuthekera popanda biocorrosion, kudziwonetsera ngati pseudoperiodic oscillations mozungulira 24:00.Malingaliro awa adatsimikiziridwa ndi Dowling et al.86 Adawonetsa ma photosynthetic biofilms a cyanobacteria Anabaena.Mpweya wosungunuka umapangidwa pansi pa ntchito ya kuwala, yomwe imagwirizanitsidwa ndi kusintha kapena kusinthasintha kwa mphamvu ya biocorrosion yaulere.Kufunika kwa photoperiod kumagogomezedwa ndi mfundo yakuti mwayi waulere wa biocorrosion umawonjezeka mu gawo lowala ndikuchepa mumdima.Izi zimachitika chifukwa cha okosijeni wopangidwa ndi photosynthetic microalgae, yomwe imakhudza kachitidwe ka cathodic kudzera pakukakamiza pang'ono komwe kumapangidwa pafupi ndi ma electrodes87.
Kuonjezera apo, Fourier transform infrared spectroscopy (FTIR) adachitidwa kuti adziwe ngati kusintha kulikonse kunachitika mu mankhwala a ma cell algae atatha kuyanjana ndi Nb-MXenes.Zotsatira zomwe tapezazi ndizovuta ndipo timaziwonetsa mu SI (Zithunzi S23-S25, kuphatikizapo zotsatira za siteji ya MAX ndi ML MXenes).Mwachidule, zomwe tapeza za microalgae zimatipatsa chidziwitso chofunikira chokhudza mawonekedwe azinthu zamoyozi.Kugwedezeka kwakukulu kumeneku kumakhala pamtunda wa 1060 cm-1 (CO), 1540 cm-1, 1640 cm-1 (C = C), 1730 cm-1 (C = O), 2850 cm-1, 2920 cm-1.imodzi.1 1 (C–H) ndi 3280 cm–1 (O–H).Kwa SL Nb-MXenes, tapeza siginecha yotambasula ya CH-bond yomwe ikugwirizana ndi phunziro lathu lapitalo38.Komabe, tidawona kuti nsonga zina zowonjezera zokhudzana ndi C = C ndi CH zomangira zidasowa.Izi zikuwonetsa kuti mankhwala a microalgae amatha kusintha pang'ono chifukwa chogwirizana ndi SL Nb-MXenes.
Poganizira kusintha komwe kungachitike mu biochemistry ya microalgae, kudzikundikira kwa ma inorganic oxides, monga niobium oxide, kuyenera kuganiziridwanso59.Zimakhudzidwa ndi kutengeka kwa zitsulo ndi selo pamwamba, kayendedwe kake kupita ku cytoplasm, kuyanjana kwawo ndi magulu a intracellular carboxyl, ndi kudzikundikira mu microalgae polyphosphosomes20,88,89,90.Kuonjezera apo, mgwirizano pakati pa microalgae ndi zitsulo umasungidwa ndi magulu ogwira ntchito a maselo.Pachifukwa ichi, kuyamwa kumadaliranso chemistry ya microalgae, yomwe ndi yovuta kwambiri9,91.Kawirikawiri, monga momwe zimayembekezeredwa, mankhwala a microalgae obiriwira anasintha pang'ono chifukwa cha kuyamwa kwa Nb oxide.
Chochititsa chidwi n'chakuti, kulepheretsa koyamba kwa microalgae kunasinthidwa pakapita nthawi.Monga tidawonera, ma microalgae adagonjetsa kusintha koyambirira kwa chilengedwe ndipo pamapeto pake adabwereranso pakukula bwino komanso kuwonjezeka.Maphunziro a kuthekera kwa zeta amawonetsa kukhazikika kwakukulu akamalowetsedwa muzofalitsa zopatsa thanzi.Choncho, kuyanjana kwapakati pakati pa maselo a microalgae ndi Nb-MXene nanoflakes kunasungidwa muzoyesa zochepetsera.Pakuwunika kwathu kwina, tikufotokozera mwachidule njira zazikulu zochitira zomwe zimayambitsa khalidwe lochititsa chidwi la microalgae.
Kuwona kwa SEM kwawonetsa kuti ma microalgae amakonda kumamatira ku Nb-MXenes.Pogwiritsa ntchito kusanthula kwachifaniziro champhamvu, timatsimikizira kuti zotsatirazi zimabweretsa kusintha kwa ma nanoflakes awiri a Nb-MXene kukhala tinthu tating'onoting'ono tozungulira, posonyeza kuti kuwonongeka kwa nanoflakes kumagwirizana ndi okosijeni.Kuti tiyese malingaliro athu, tidachita maphunziro angapo azinthu zakuthupi ndi zamankhwala.Pambuyo kuyezetsa, ma nanoflakes pang'onopang'ono amathiridwa okosijeni ndikuwola kukhala zinthu za NbO ndi Nb2O5, zomwe sizinawopseze ma microalgae obiriwira.Pogwiritsa ntchito kuwonetsetsa kwa FTIR, sitinapeze kusintha kwakukulu kwa mankhwala a microalgae omwe amapangidwa pamaso pa 2D Nb-MXene nanoflakes.Poganizira za kuthekera kwa kuyamwa kwa niobium oxide ndi microalgae, tidachita kusanthula kwa X-ray fluorescence.Zotsatira izi zikuwonetsa momveka bwino kuti ma microalgae omwe amaphunzira amadya ma niobium oxides (NbO ndi Nb2O5), omwe alibe poizoni kwa ma microalgae omwe amaphunzira.