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ʻO ka hoʻomohala wikiwiki o ka nanotechnology a me kona hoʻohui ʻana i nā noi o kēlā me kēia lā hiki ke hoʻoweliweli i ke kaiapuni. ʻOiai ua hoʻokumu maikaʻi ʻia nā ala ʻōmaʻomaʻo no ka hoʻohaumia ʻana o nā mea haumia, ʻo ka hoʻihoʻi ʻana o nā mea hoʻohaumia crystalline inorganic he mea hopohopo nui ma muli o ko lākou haʻahaʻa haʻahaʻa i ka biotransformation a me ka ʻike ʻole o ka pili ʻana o ka honua me nā mea olaola. Maʻaneʻi, hoʻohana mākou i ka Nb-based inorganic 2D MXenes model i hui pū ʻia me kahi ʻano hoʻohālikelike hoʻohālikelike maʻalahi e ʻimi i ke ʻano bioremediation o 2D ceramic nanomaterials e ka microalgae ʻōmaʻomaʻo Raphidocelis subcapitata. Ua ʻike mākou ua hoʻohaʻahaʻa ka microalgae i nā MXenes e pili ana i ka Nb ma muli o nā pilina pili kino-kemika pili i ka ʻili. I ka hoʻomaka ʻana, ua hoʻopili ʻia nā nanoflakes MXene one-layer a me multilayer i ka ʻili o nā microalgae, kahi i hoʻemi iki i ka ulu ʻana o nā algae. Eia naʻe, ma ka lōʻihi o ka launa pū ʻana me ka ʻili, ua hoʻoheheʻe ʻia ka microalgae i nā nanoflakes MXene a hoʻopau hou iā lākou i NbO a me Nb2O5. No ka mea, ʻaʻohe mea ʻawaʻawa kēia mau oxides i nā cell microalgae, hoʻopau lākou i nā nanoparticles Nb oxide e kahi hana absorption e hoʻihoʻi hou i ka microalgae ma hope o 72 mau hola o ka mālama ʻana i ka wai. Hōʻike ʻia nā hopena o nā meaʻai e pili ana i ka absorption i ka piʻi ʻana o ka nui o nā cell, ko lākou ʻano maʻalahi a me ka loli o ka ulu ulu. Ma muli o kēia mau ʻike, manaʻo mākou ʻo ka noho pōkole a me ka lōʻihi o nā MXenes i hoʻokumu ʻia i ka Nb i loko o nā kaiaola wai maʻemaʻe hiki ke hoʻopilikia wale i nā hopena kaiapuni. He mea pono ia, me ka hoʻohana ʻana i nā nanomaterial ʻelua-dimensional e like me nā ʻōnaehana kumu hoʻohālike, hōʻike mākou i ka hiki ke nānā i ka hoʻololi ʻana i ke ʻano ʻoiai i loko o nā mea momona maikaʻi. Ma ka holoʻokoʻa, pane kēia noiʻi i kahi nīnau koʻikoʻi e pili ana i nā kaʻina pili pili i ka honua e hoʻokele ana i ka mīkini bioremediation o 2D nanomaterials a hāʻawi i kumu no ka hoʻopaʻa ʻana i ka wā pōkole a me ka lōʻihi o ka hopena o ke kaiapuni o nā nanomaterial crystalline inorganic.
Ua hoʻoulu nui ʻia nā nanomaterials mai ko lākou ʻike ʻia ʻana, a ua komo hou nā ʻano ʻenehana nano i kahi manawa hou 1. ʻO ka mea pōʻino, hiki i ka hoʻohui ʻana o nā nanomaterials i nā noi i kēlā me kēia lā ke alakaʻi i ka hoʻokuʻu ʻia ʻana ma muli o ka hoʻokuʻu pono ʻole, ka mālama mālama ʻole ʻana, a i ʻole ka pono ʻole o nā ʻōnaehana palekana. No laila, he mea kūpono ke manaʻo e hiki ke hoʻokuʻu ʻia nā nanomaterials, me nā nanomaterial ʻelua-dimensional (2D) i loko o ke kaiapuni kūlohelohe, ʻaʻole maopopo loa ka ʻano a me ka hana olaola. No laila, ʻaʻole ia he mea kupanaha no ka pili ʻana o ka ecotoxicity i ka hiki o 2D nanomaterials e leʻa i loko o nā ʻōnaehana wai2,3,4,5,6. I loko o kēia mau kaiaola, hiki i kekahi mau nanomaterials 2D ke launa pū me nā mea ola like ʻole ma nā pae trophic like ʻole, me ka microalgae.
ʻO nā microalgae nā mea ola mua loa i loaʻa maoli i loko o ka wai maʻemaʻe a me nā kaiaola kai e hana ana i nā ʻano huahana kemika ma o photosynthesis7. No laila, he mea koʻikoʻi lākou i nā kaiaolaola8,9,10,11,12 akā he mau hōʻailona koʻikoʻi, kūʻai ʻole a hoʻohana nui ʻia o ka ecotoxicity13,14. Ma muli o ka hoʻonui ʻana o nā cell microalgae me ka wikiwiki a pane koke i ka hiki ʻana mai o nā pūhui like ʻole, ke hoʻohiki nei lākou no ka hoʻomohala ʻana i nā ʻano ʻano pili i ke kaiapuni no ka mālama ʻana i ka wai i haumia i nā mea ola15,16.
Hiki i nā pūnaewele algae ke wehe i nā ion inorganic mai ka wai ma o ka biosorption a me ka accumulation17,18. ʻO kekahi mau ʻano alga e like me Chlorella, Anabaena invar, Westiellopsis prolifica, Stigeoclonium tenue a me Synechococcus sp. Ua ʻike ʻia e lawe a hānai i nā ion metala ʻona e like me Fe2+, Cu2+, Zn2+ a me Mn2+19. Ua hōʻike ʻia nā haʻawina ʻē aʻe ʻo Cu2+, Cd2+, Ni2+, Zn2+ a i ʻole Pb2+ ion e kaupalena i ka ulu ʻana o Scenedesmus ma ka hoʻololi ʻana i ka morphology cell a luku i kā lākou chloroplasts20,21.
ʻO nā ʻano ʻōmaʻomaʻo no ka hoʻoheheʻe ʻana i nā mea haumia organik a me ka wehe ʻana i nā ion metala kaumaha ua hoʻohuli i ka manaʻo o nā ʻepekema a me nā ʻenekinia a puni ka honua. ʻO ka mea nui kēia ma muli o ka maʻalahi o kēia mau mea haumia i ka hana wai. Eia naʻe, ʻike ʻia nā mea hoʻohaumia crystalline inorganic e ka haʻahaʻa haʻahaʻa o ka wai a me ka haʻahaʻa haʻahaʻa i nā biotransformations like ʻole, ka mea e pilikia nui ai i ka hoʻoponopono ʻana, a ua liʻiliʻi ka holomua ma kēia wahi22,23,24,25,26. No laila, ʻo ka ʻimi ʻana i nā ʻoluʻolu pili kaiapuni no ka hoʻoponopono ʻana i nā nanomaterials e noho paʻakikī a ʻike ʻole ʻia. Ma muli o ke kūlana kiʻekiʻe o ka maopopo ʻole e pili ana i nā hopena biotransformation o 2D nanomaterials, ʻaʻohe ala maʻalahi e ʻike ai i nā ala hiki ke hoʻohaʻahaʻa ʻia i ka wā o ka hōʻemi.
Ma kēia noiʻi ʻana, ua hoʻohana mākou i ka microalgae ʻōmaʻomaʻo ma ke ʻano he mea hana bioremediation aqueous no nā mea ceramic inorganic, i hui pū ʻia me ka nānā ʻana i ke kaʻina hana hoʻohaʻahaʻa o MXene ma ke ʻano he ʻelele o nā mea ceramic inorganic. Hōʻike ka huaʻōlelo “MXene” i ka stoichiometry o ka mea Mn+1XnTx, kahi o M he metala hoʻololi mua, ʻo X ke kalapona a/a i ʻole ka nitrogen, ʻo Tx kahi mea hoʻopau ʻili (e laʻa, -OH, -F, -Cl), a me n = 1, 2, 3 a i ʻole 427.28. Mai ka loaʻa ʻana o MXenes e Naguib et al. ʻO ka sensorics, ka maʻi kanesa a me ka kānana membrane 27,29,30. Eia hou, hiki ke noʻonoʻo ʻia ʻo MXenes e like me nā ʻōnaehana 2D kumu hoʻohālike ma muli o ko lākou kūpaʻa colloidal maikaʻi loa a hiki i nā pilina olaola31,32,33,34,35,36.
No laila, ua hōʻike ʻia ke ʻano hana ma kēia ʻatikala a me kā mākou mau kuhiakau noiʻi ma ke Kiʻi 1. Wahi a kēia kuhiakau, hoʻohaʻahaʻa ka microalgae i ka MXenes i hoʻokumu ʻia i ka Nb i loko o nā pūhui mea ʻawaʻawa ʻole ma muli o nā pilina pili kino-kemika e pili ana i ka ʻili, e hiki ai ke hoʻihoʻi hou i ka algae. No ka hoʻāʻo ʻana i kēia kuhiakau, ua koho ʻia nā lālā ʻelua o ka ʻohana o ka niobium-based transition metal carbide a/a i ʻole nitrides (MXenes), ʻo ia hoʻi ʻo Nb2CTx a me Nb4C3TX.
ʻO ke ʻano noiʻi a me nā kuhiakau e pili ana i nā hōʻike no ka hoʻihoʻi ʻana o MXene e ka microalgae ʻōmaʻomaʻo Raphidocelis subcapitata. E ʻoluʻolu e hoʻomaopopo he hōʻike schematic wale nō kēia o nā manaʻo e pili ana i nā hōʻike. 'Oko'a ke kaiapuni o ka loko i ka mea waiwai i ho'ohana 'ia a me nā kūlana (e la'a, ka pō'ai o ka lā a me nā palena o nā mea'ai pono i loa'a). Hana ʻia me BioRender.com.
No laila, ma ka hoʻohana ʻana iā MXene ma ke ʻano he kumu hoʻohālike, ua wehe mākou i ka puka no ke aʻo ʻana i nā hopena olaola like ʻole i hiki ʻole ke nānā ʻia me nā nanomaterials maʻamau. Ma keʻano kūikawā, hōʻike mākou i ka hiki ke bioremediation o nā nanomaterials ʻelua-dimensional, e like me ka MXenes kumu niobium, e ka microalgae Raphidocelis subcapitata. Hiki i ka Microalgae ke hoʻohaʻahaʻa i nā Nb-MXenes i loko o nā oxides non-toxic NbO a me Nb2O5, e hāʻawi pū ana i nā meaʻai ma o ka hana hoʻopiʻi niobium. ʻO ka holoʻokoʻa, pane kēia haʻawina i kahi nīnau koʻikoʻi e pili ana i nā kaʻina hana e pili ana i ka pilina physicochemical ili e hoʻokele i nā hana o ka bioremediation o nā nanomaterial ʻelua-dimensional. Eia hou, ke hoʻomohala nei mākou i kahi ala maʻalahi e pili ana i ke ʻano-parameter no ka nānā ʻana i nā loli maʻalahi i ke ʻano o nā nanomaterials 2D. Hoʻoulu kēia i ka noiʻi no ka wā pōkole a me ka wā lōʻihi i nā hopena kaiapuni like ʻole o nā nanomaterial crystalline inorganic. No laila, hoʻonui kā mākou haʻawina i ka hoʻomaopopo ʻana i ka pilina ma waena o ka ʻili waiwai a me nā mea olaola. Ke hāʻawi nei mākou i ke kumu no ka hoʻonui ʻia ʻana o nā haʻawina no ka wā pōkole a me ka wā lōʻihi e pili ana i ko lākou hopena i nā kaiaola wai piha, hiki ke hōʻoia maʻalahi i kēia manawa.
Hōʻike ʻo MXenes i kahi papa hoihoi o nā mea me nā waiwai kino a me nā waiwai kemika a no laila he nui nā noi. Pili nui kēia mau waiwai i kā lākou stoichiometry a me ke kemika ʻili. No laila, i kā mākou noiʻi ʻana, ua noiʻi mākou i ʻelua ʻano o Nb-based hierarchical single-layer (SL) MXenes, Nb2CTx a me Nb4C3TX, no ka mea hiki ke ʻike ʻia nā hopena olaola like ʻole o kēia mau nanomaterials. Hoʻokumu ʻia nā MXenes mai kā lākou mau mea hoʻomaka e ka hoʻoheheʻe ʻia ʻana ma luna o lalo o nā ʻāpana A-ʻoi aku ka lahilahi MAX-phase. ʻO ka māhele MAX he keramic ternary i haku ʻia me nā poloka "hoʻopaʻa ʻia" o nā carbide metala hoʻololi a me nā ʻāpana lahilahi o nā mea "A" e like me Al, Si, a me Sn me MnAXn-1 stoichiometry. Ua ʻike ʻia ka morphology o ka pae mua MAX e ka nānā ʻana i ka microscopy electron (SEM) a ua kūlike me nā haʻawina mua (E nānā i ka ʻIke Hoʻohui, SI, Kiʻi S1). Loaʻa ka Multilayer (ML) Nb-MXene ma hope o ka wehe ʻana i ka papa Al me 48% HF (hydrofluoric acid). Ua nānā ʻia ka morphology o ML-Nb2CTx a me ML-Nb4C3TX e ka scanning electron microscopy (SEM) (Figures S1c and S1d each) a ua ʻike ʻia kahi morphology layered MXene, e like me nā nanoflakes ʻelua-dimensional e hele ana ma nā ʻāpana elongated pore-like. Loaʻa nā Nb-MXene ʻelua me nā māhele MXene i hana mua ʻia e ka acid etching27,38. Ma hope o ka hōʻoia ʻana i ke ʻano o MXene, ua hoʻopaʻa mākou iā ia ma ka intercalation o tetrabutylammonium hydroxide (TBAOH) i ukali ʻia e ka holoi ʻana a me ka sonication, ma hope o ka loaʻa ʻana o ka nanoflakes hoʻokahi a i ʻole nā ​​​​mea haʻahaʻa (SL) 2D Nb-MXene.
Ua hoʻohana mākou i ka microscopy electron transmission high resolution (HRTEM) a me X-ray diffraction (XRD) e hoʻāʻo ai i ka pono o ka etching a me ka ʻili hou ʻana. Hōʻike ʻia nā hopena HRTEM me ka hoʻohana ʻana i ka Inverse Fast Fourier Transform (IFFT) a me Fast Fourier Transform (FFT) ma ke kiʻi. Hōʻike ʻia nā kiʻi HRTEM o MXene Nb2CTx a me Nb4C3TX nanoflakes i ko lākou ʻano atomically thin layered (e nānā i ka Fig. 2a1, a2), e like me ka mea i hōʻike mua ʻia e Naguib et al.27 a me Jastrzębska et al.38. No ʻelua mau monolayer Nb2CTx a me Nb4C3Tx pili, ua hoʻoholo mākou i nā mamao interlayer o 0.74 a me 1.54 nm, i kēlā me kēia (Fig. 2b1,b2), i ʻae pū me kā mākou hopena mua38. Ua hōʻoia hou ʻia kēia e ka hoʻololi hou ʻana o Fourier wikiwiki (Fig. 2c1, c2) a me ka wikiwiki Fourier transform (Fig. 2d1, d2) e hōʻike ana i ka mamao ma waena o nā Nb2CTx a me Nb4C3Tx monolayers. Hōʻike ke kiʻi i ka hoʻololi ʻana o nā kaula māmā a me nā ʻeleʻele e pili ana i ka niobium a me nā ʻātoma kalapona, e hōʻoia ana i ke ʻano papa o nā MXenes i aʻo ʻia. He mea nui e hoʻomaopopo i ka ikehu dispersive X-ray spectroscopy (EDX) spectra i loaʻa no Nb2CTx a me Nb4C3Tx (Figures S2a a me S2b) i hōʻike ʻole i ke koena o ka pae mua MAX, no ka mea, ʻaʻohe kiʻekiʻe Al i ʻike ʻia.
Ke ano o ka SL Nb2CTx a me ka Nb4C3Tx MXene nanoflakes, me (a) kiʻi kiʻi electron microscopy (HRTEM) ʻaoʻao 2D nanoflake kiʻi a me ka mea like, (b) ke ʻano ikaika, (c) inverse fast Fourier transform (IFFT), (d) Fast Fourier transform (FFT), (e) X Nb-MXene patterns. No SL 2D Nb2CTx, ua hōʻike ʻia nā helu e like me (a1, b1, c1, d1, e1). No SL 2D Nb4C3Tx, hōʻike ʻia nā helu e like me (a2, b2, c2, d2, e1).
Hōʻike ʻia nā ana ʻokoʻa X-ray o SL Nb2CTx a me Nb4C3Tx MXenes ma Fig. 2e1 a me e2. ʻO Peaks (002) ma 4.31 a me 4.32 e pili ana i ka MXenes Nb2CTx i wehewehe mua ʻia a me Nb4C3TX38,39,40,41. Hōʻike pū nā hualoaʻa XRD i ka loaʻa ʻana o kekahi mau kūkulu ML koena a me nā pae MAX, akā ʻo ka hapa nui o nā kumu XRD pili me SL Nb4C3Tx (Fig. 2e2). ʻO ka hiki ʻana mai o nā mea liʻiliʻi liʻiliʻi o ka pae MAX hiki ke wehewehe i ka ʻoi aku ka ikaika o ka piko MAX i hoʻohālikelike ʻia me nā papa Nb4C3Tx i hoʻopaʻa ʻia.
ʻO nā noiʻi hou aʻe i kālele ʻia i nā microalgae ʻōmaʻomaʻo no ka ʻano R. subcapitata. Ua koho mākou i ka microalgae no ka mea he mau mea hana nui lākou i loko o nā pūnaewele meaʻai nui42. ʻO ia kekahi o nā hōʻailona maikaʻi loa o ka ʻawaʻawa ma muli o ka hiki ke wehe i nā mea ʻona e lawe ʻia i nā pae kiʻekiʻe o ke kaulahao meaʻai43. Eia hou, hiki i ka noiʻi ʻana ma R. subcapitata ke hoʻomālamalama i ka ʻawaʻawa o SL Nb-MXenes i nā microorganism maʻamau maʻamau. No ka hōʻike ʻana i kēia, ua kuhi ka poʻe noiʻi he ʻokoʻa ke ʻano o kēlā me kēia microbe i nā mea ʻona i loko o ke kaiapuni. No ka hapa nui o nā mea ola, ʻaʻole pili ka haʻahaʻa haʻahaʻa o nā mea i ko lākou ulu ʻana, ʻoiai ʻo ka ʻike ʻana ma luna o kekahi palena hiki ke hōʻole iā lākou a make paha. No laila, no kā mākou noiʻi ʻana i ka pilina ma waena o nā microalgae a me MXenes a me ka hoʻihoʻi ʻana i pili, ua hoʻoholo mākou e hoʻāʻo i nā ʻano ʻino a me nā mea ʻawaʻawa o Nb-MXenes. No ka hana ʻana i kēia, ua hoʻāʻo mākou i nā manaʻo o ka 0 (ma ke ʻano he kuhikuhi), 0.01, 0.1 a me 10 mg l-1 MXene a me nā microalgae i hoʻopili ʻia me nā kiʻekiʻe kiʻekiʻe o MXene (100 mg l-1 MXene), hiki ke ʻoi loa a make. . no kekahi kaiaola olaola.
Hōʻike ʻia nā hopena o SL Nb-MXenes ma nā microalgae ma ke Kiʻi 3, i hōʻike ʻia ma ke ʻano o ka pākēneka o ka hoʻoulu ulu ʻana (+) a i ʻole ka inhibition (-) i ana ʻia no 0 mg l-1 samples. No ka hoʻohālikelike, ua hoʻāʻo ʻia ka pae Nb-MAX a me ML Nb-MXenes a hōʻike ʻia nā hopena ma SI (e ʻike i ka Fig. S3). Ua hōʻoia nā hualoaʻa i loaʻa i ka SL Nb-MXenes aneane nele loa i nā meaʻawaʻawa ma ka laulā o nā haʻahaʻa haʻahaʻa mai ka 0.01 a hiki i ka 10 mg / l, e like me ka mea i hōʻikeʻia ma ka Fig. 3a,b. I ka hihia o Nb2CTx, ua ʻike mākou ʻaʻole i ʻoi aku ma mua o 5% ecotoxicity i ka pae i ʻōlelo ʻia.
ʻO ka hoʻouluʻana (+) a iʻole ke kāohi (-) o ka uluʻana o ka microalgae i mua o SL (a) Nb2CTx a me (b) Nb4C3TX MXene. 24, 48 a me 72 mau hola o ka pilina MXene-microalgae i kālailai ʻia. Ua hōʻailona ʻia nā ʻikepili koʻikoʻi (t-test, p <0.05) me kahi asterisk (*). Ua hōʻailona ʻia nā ʻikepili koʻikoʻi (t-test, p <0.05) me kahi asterisk (*). Значимые данные (t-критерий, p < 0,05) отмечены звездочкой (*). Hōʻailona ʻia nā ʻikepili koʻikoʻi (t-test, p <0.05) me kahi 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 (*). Hōʻailona ʻia nā ʻikepili koʻikoʻi (t-test, p <0.05) me kahi asterisk (*).Hōʻike nā pua ʻulaʻula i ka hoʻopau ʻana i ka hoʻoulu ʻana i ka inhibitory.
Ma ka ʻaoʻao ʻē aʻe, ua lilo nā haʻahaʻa haʻahaʻa o Nb4C3TX i mea ʻawaʻawa, akā ʻaʻole i kiʻekiʻe ma mua o 7%. E like me ka mea i manaʻo ʻia, ua ʻike mākou he ʻoi aku ka nui o ka toxicity a me ka microalgae ulu inhibition ma 100mg L-1. ʻO ka mea mahalo, ʻaʻohe o nā mea i hōʻike i ke ʻano like a me ka hilinaʻi manawa o nā hopena atoxic/toxic i hoʻohālikelike ʻia i nā mea hoʻohālike MAX a i ʻole ML (e ʻike iā SI no nā kikoʻī). ʻOiai no ka pae MAX (e nānā i ka Fig. S3) hiki i ka toxicity ma kahi o 15-25% a hoʻonui ʻia me ka manawa, ua ʻike ʻia ke ʻano hoʻohuli no SL Nb2CTx a me Nb4C3TX MXene. Ua emi iho ka pale ʻana i ka ulu ʻana o ka microalgae i ka manawa. Ua hōʻea ma kahi o 17% ma hope o 24 mau hola a hāʻule i lalo o 5% ma hope o 72 mau hola (Fig. 3a, b, kēlā me kēia).
ʻOi aku ka mea nui, no SL Nb4C3TX, hiki i ka ulu ʻana o ka microalgae inhibition ma kahi o 27% ma hope o 24 mau hola, akā ma hope o 72 mau hola ua emi iho i kahi o 1%. No laila, ua kapa inoa mākou i ka hopena i ʻike ʻia ma ke ʻano he inhibition inverse o ka hoʻoulu ʻana, a ʻoi aku ka ikaika o ka hopena no SL Nb4C3TX MXene. Uaʻike muaʻia ka hoʻouluʻana i ka uluʻana o ka microalgae me Nb4C3TX (ka pilina ma 10 mg L-1 no 24 h) i ka hoʻohālikelikeʻana me SL Nb2CTx MXene. Ua hōʻike maikaʻi ʻia ka hopena inhibition-stimulation reversal i ka biomass double rate curve (e nānā i ka Fig. S4 no nā kikoʻī). I kēia manawa, ua aʻo ʻia ka ecotoxicity o Ti3C2TX MXene ma nā ʻano like ʻole. ʻAʻole ia he mea ʻawaʻawa i nā embryos iʻa zebra44 akā he mea ʻona i ka microalgae Desmodesmus quadricauda a me nā mea kanu Sorghum saccharatum45. ʻO nā hiʻohiʻona ʻē aʻe o nā hopena kikoʻī e pili ana i ka ʻona ʻoi aku ka kiʻekiʻe o nā laina cell cancer ma mua o nā laina cell maʻamau46,47. Hiki ke manaʻo ʻia e hoʻololi nā kūlana hoʻokolohua i nā loli i ka ulu ʻana o ka microalgae i ʻike ʻia ma ke alo o Nb-MXenes. No ka laʻana, ʻoi aku ka maikaʻi o ka pH ma kahi o 8 i ka stroma chloroplast no ka hana pono o ka enzyme RuBisCO. No laila, hoʻololi ʻino ka pH i ka wikiwiki o ka photosynthesis48,49. Akā naʻe,ʻaʻole mākou iʻike i nā loli nui i ka pH i ka wā o ka hoʻokolohua (e nānā i ka SI, Fig. S5 no nā kiko'ī). Ma keʻano laulā, hoʻemi iki nā moʻomeheu microalgae me Nb-MXenes i ka pH o ka hopena i ka manawa. Eia naʻe, ua like kēia emi ʻana me ka hoʻololi ʻana i ka pH o kahi mea maʻemaʻe. Eia hou, ua like ka laula o nā ʻano like ʻole me ka mea i ana ʻia no ka moʻomeheu maʻemaʻe o ka microalgae (nā mea hoʻomalu). No laila, manaʻo mākou ʻaʻole pili ka photosynthesis e nā loli i ka pH i ka manawa.
Eia kekahi, loaʻa i nā MXenes synthesized nā hopena ili (i kapa ʻia ʻo Tx). ʻO kēia nā pūʻulu hana nui -O, -F a me -OH. Eia nō naʻe, pili pono ka kemika ʻili i ke ʻano o ka synthesis. Ua ʻike ʻia kēia mau pūʻulu e hoʻohele like ʻole ʻia ma luna o ka ʻili, he mea paʻakikī ke wānana i ko lākou hopena i nā waiwai o MXene50. Hiki ke hoʻopaʻapaʻa ʻia ʻo Tx ka ikaika catalytic no ka oxidation o ka niobium e ka mālamalama. Hāʻawi maoli nā pūʻulu hana o Surface i nā pūnaewele heleuma he nui no kā lākou photocatalysts lalo e hana i nā heterojunctions51. Eia naʻe, ʻaʻole i hāʻawi ʻia ka haku mele ulu i kahi photocatalyst maikaʻi (hiki ke loaʻa ka haku mele kikoʻī ma ka SI Table S6). Eia hou, he mea ko'iko'i loa ka ho'ololi 'ana o ka ili, no ka mea, hiki ke ho'ololi 'ia ka hana olaola o MXenes ma muli o ka ho'oponopono 'ana ma hope o ka ho'ohehe'e 'ana, ka ho'ololi 'ilikai kemika o nā pūhui mea ola a me nā mea 'ole52,53,54,55,56 a i 'ole ka 'enekinia uku luna38. No laila, no ka hoʻāʻo ʻana inā pili ka niobium oxide me ka paʻa ʻole o nā mea i loko o ke kikowaena, ua hana mākou i nā noiʻi o ka zeta (ζ) hiki i ka microalgae ulu ulu a me ka wai deionized (no ka hoʻohālikelike). Hōʻike kā mākou mau hopena i ka paʻa pono o SL Nb-MXenes (e ʻike iā SI Fig. S6 no nā hopena MAX a me ML). ʻO ka mana zeta o SL MXenes ma kahi o -10 mV. Ma ka hihia o SR Nb2CTx, ʻoi aku ka maikaʻi o ka waiwai o ζ ma mua o ko Nb4C3Tx. ʻO ia hoʻololi ʻana i ka waiwai ζ e hōʻike ana i ka ʻili o nā nanoflakes MXene i hoʻopiʻi ʻole ʻia e hoʻopaʻa i nā ion i hoʻopiʻi maikaʻi ʻia mai ka moʻomeheu moʻomeheu. ʻO nā ana manawa o ka hiki zeta a me ka conductivity o Nb-MXenes ma ka moʻomeheu moʻomeheu (e nānā i nā Kiʻi S7 a me S8 ma SI no nā kikoʻī hou aku) e kākoʻo ana i kā mākou kuhiakau.
Eia naʻe, hōʻike nā Nb-MXene SL ʻelua i nā loli liʻiliʻi mai ka ʻole. Hōʻike maopopo kēia i ko lākou kūpaʻa i ka microalgae ulu ulu. Eia hou, ua loiloi mākou inā pili ka hiki ʻana o kā mākou microalgae ʻōmaʻomaʻo i ka paʻa o Nb-MXenes i ka waena. Hiki ke loaʻa nā hopena o ka hiki zeta a me ka conductivity o MXenes ma hope o ka launa pū ʻana me nā microalgae i ka media nutrient a me ka moʻomeheu i ka wā lōʻihi e hiki ke loaʻa ma SI (Figures S9 a me S10). ʻO ka mea mahalo, ua ʻike mākou i ka hiki ʻana mai o nā microalgae e hoʻopaʻa i ka hoʻopuehu ʻana o nā MXene ʻelua. I ka hihia o Nb2CTx SL, ua emi iki ka mana o ka zeta i ka manawa i nā waiwai maikaʻi ʻole (-15.8 versus -19.1 mV ma hope o 72 mau hola o ka incubation). Ua piʻi iki ka zeta hiki o SL Nb4C3TX, akā ma hope o 72 h ua hōʻike mau ʻo ia i ke kūpaʻa kiʻekiʻe ma mua o nā nanoflakes me ka ʻole o ka microalgae (-18.1 vs. -9.1 mV).
Ua ʻike pū mākou i ka haʻahaʻa haʻahaʻa o nā Nb-MXene solution i hoʻomoʻa ʻia i mua o ka microalgae, e hōʻike ana i kahi haʻahaʻa o nā ion i loko o ka meaʻai. ʻO ka mea nui, ʻo ka instability o MXenes i loko o ka wai ma muli o ka oxidation ili57. No laila, ke manaʻo nei mākou ua hoʻomaʻemaʻe ka microalgae ʻōmaʻomaʻo i nā oxides i hana ʻia ma luna o ka ʻili o Nb-MXene a pale pū i ko lākou hanana ʻana (oxidation of MXene). Hiki ke ʻike ʻia kēia ma ke aʻo ʻana i ke ʻano o nā mea i komo ʻia e ka microalgae.
ʻOiai ua hōʻike kā mākou mau haʻawina ecotoxicological ua hiki i ka microalgae ke lanakila i ka ʻawaʻawa o Nb-MXenes i ka manawa a me ka pale ʻole o ka ulu ʻana i hoʻoulu ʻia, ʻo ka pahuhopu o kā mākou noiʻi ʻana e noiʻi i nā hana hiki ke hana. Ke ʻike ʻia nā mea ola e like me ka limu i nā pūhui a i ʻole nā ​​​​mea i ʻike ʻole ʻia i ko lākou kaiaola, hiki iā lākou ke hana ma nā ʻano like ʻole58,59. I ka loaʻa ʻole o nā oxide metala ʻona, hiki i nā microalgae ke hānai iā lākou iho, e ʻae iā lākou e ulu mau. Ma hope o ka ʻai ʻana i nā mea ʻawaʻawa, hiki ke hoʻāla ʻia nā mīkini pale, e like me ka hoʻololi ʻana i ke ʻano a i ʻole ke ʻano. Pono e noʻonoʻo ʻia ka hiki o ka absorption58,59. ʻO ka mea nui, ʻo kēlā me kēia hōʻailona o kahi mīkini pale he hōʻailona maopopo o ka ʻona o ka pūhui hoʻāʻo. No laila, i kā mākou hana hou aku, ua noiʻi mākou i ka pilina ma waena o SL Nb-MXene nanoflakes a me nā microalgae e SEM a me ka hiki ke komo ʻana o Nb-based MXene e X-ray fluorescence spectroscopy (XRF). E hoʻomanaʻo, ua hana wale ʻia nā loiloi SEM a me XRF ma ke kiʻekiʻe kiʻekiʻe o MXene e hoʻoponopono i nā pilikia ʻona.
Hōʻike ʻia nā hopena SEM ma Fig.4. ʻO nā pūnaewele microalgae i mālama ʻole ʻia (e ʻike i ka Fig. 4a, hōʻike hōʻike) hōʻike maopopo ʻia i ka morphology R. subcapitata maʻamau a me ke ʻano o ka cell croissant-like. ʻIke ʻia nā kelepona palahalaha a ʻano ʻino ʻole. ʻO kekahi mau microalgae i uhi a pili pū kekahi me kekahi, akā naʻe ma muli paha o ke kaʻina hana hoʻomākaukau. Ma keʻano laulā, he maʻemaʻe ka ʻili o nā cell microalgae maʻemaʻe a ʻaʻole hōʻike i nā loli morphological.
Nā kiʻi SEM e hōʻike ana i ka launa pū ʻana ma waena o nā microalgae ʻōmaʻomaʻo a me MXene nanosheets ma hope o 72 mau hola o ka launa pū ʻana ma ke ʻano koʻikoʻi (100 mg L-1). (a) ʻO microalgae ʻōmaʻomaʻo ʻaʻole i mālama ʻia ma hope o ka launa pū ʻana me SL (b) Nb2CTx a me (c) Nb4C3TX MXenes. E hoʻomanaʻo, ua kaha ʻia nā nanoflakes Nb-MXene me nā pua ʻulaʻula. No ka hoʻohālikelike, hoʻohui pū ʻia nā kiʻi mai kahi microscope optical.
I ka hoʻokaʻawale ʻana, ua hōʻino ʻia nā cell microalgae adsorbed e SL Nb-MXene nanoflakes (e nānā i ka Fig. 4b, c, nā pua ʻulaʻula). I ka hihia o Nb2CTx MXene (Fig. 4b), ulu nā microalgae me nā nanoscales ʻelua-dimensional i hoʻopili ʻia, hiki ke hoʻololi i kā lākou morphology. ʻO ka mea nui, ua nānā mākou i kēia mau hoʻololi ma lalo o ka microscopy māmā (e ʻike iā SI Figure S11 no nā kikoʻī). He kumu kūpono kēia hoʻololi morphological i ka physiology o microalgae a me ko lākou hiki ke pale iā lākou iho ma o ka hoʻololi ʻana i ka morphology cell, e like me ka hoʻonui ʻana i ka volume cell61. No laila, he mea nui e nānā i ka helu o nā microalgae cell i pili maoli me Nb-MXenes. Ua hōʻike ʻia nā haʻawina SEM ma kahi o 52% o nā cell microalgae i hōʻike ʻia iā Nb-MXenes, aʻo 48% o kēia mau microalgae cell i pale aku i ka pilina. No SL Nb4C3Tx MXene, ho'āʻo nā microalgae e pale aku i ka pilina me MXene, no laila e hoʻokaʻawale a ulu mai nā nanoscales ʻelua-dimensional (Fig. 4c). Eia naʻe, ʻaʻole mākou i ʻike i ke komo ʻana o nā nanoscales i nā cell microalgae a me kā lākou pōʻino.
ʻO ka mālama ʻana iā ia iho he ʻano pane e pili ana i ka manawa i ka blockage o photosynthesis ma muli o ka adsorption o nā ʻāpana ma ka ʻili pūnaewele a me ka hopena i kapa ʻia ʻo shading (shading)62. Ua maopopo i kēlā me kēia mea (no ka laʻana, Nb-MXene nanoflakes) aia ma waena o ka microalgae a me ke kumu kukui e kaupalena ʻia ka nui o ka mālamalama i hoʻomoʻa ʻia e nā chloroplasts. Eia naʻe, ʻaʻohe o mākou kānalua he hopena koʻikoʻi kēia i nā hopena i loaʻa. E like me ka mea i hōʻike ʻia e kā mākou mau ʻike microscopic, ʻaʻole i ʻōwili piha ʻia nā nanoflakes 2D i ka ʻili o ka microalgae, ʻoiai i ka wā i hoʻopili ai nā cell microalgae me Nb-MXenes. Akā, ua huli ʻia nā nanoflakes i nā cell microalgae me ka uhi ʻole ʻana i ko lākou ʻili. ʻAʻole hiki i kēlā ʻano o nā nanoflakes/microalgae ke kaupalena nui i ka nui o ka mālamalama i hoʻopaʻa ʻia e nā cell microalgae. Eia kekahi, ua hōʻike kekahi mau haʻawina i ka hoʻomaikaʻi ʻana i ka absorption māmā e nā mea ola photosynthetic i mua o nā nanomaterials ʻelua-dimensional63,64,65,66.
Ma muli o ka hiki ʻole i nā kiʻi SEM ke hōʻoia pololei i ka lawe ʻana o ka niobium e nā pūnaewele microalgae, ua huli kā mākou noiʻi hou i ka X-ray fluorescence (XRF) a me ka X-ray photoelectron spectroscopy (XPS) analysis e wehewehe i kēia pilikia. No laila, ua hoʻohālikelike mākou i ka ikaika o ka Nb peaks o nā microalgae kumu hoʻohālike i pili ʻole me MXenes, MXene nanoflakes i wehe ʻia mai ka ʻili o nā pūnaewele microalgae, a me nā cell microalgal ma hope o ka wehe ʻana i nā MXenes pili. He mea pono e hoʻomaopopo inā ʻaʻohe Nb uptake, ʻo ka waiwai Nb i loaʻa i nā cell microalgae he zero ma hope o ka wehe ʻana i nā nanoscales i hoʻopili ʻia. No laila, inā loaʻa ka Nb uptake, pono nā hopena XRF a me XPS e hōʻike i kahi piko Nb maopopo.
I ka hihia o XRF spectra, microalgae samples hoike Nb peaks no SL Nb2CTx a me Nb4C3Tx MXene ma hope o ka launa pū ana me SL Nb2CTx a me Nb4C3Tx MXene (e nānā i ka Fig. 5a, e hoʻomaopopo pū i nā hualoaʻa no MAX a me ML MXenes i hōʻikeʻia ma SI, Fig S12-C17). ʻO ka mea e mahalo ai, ua like ka ikaika o ka piko Nb i nā hihia ʻelua (nā pahu ʻulaʻula ma Fig. 5a). Ua hōʻike kēia ʻaʻole hiki i ka algae ke komo i nā Nb hou aʻe, a ua hoʻokō ʻia ka mana kiʻekiʻe no ka hōʻiliʻili ʻana o Nb i loko o nā keena, ʻoiai ʻelua manawa i hoʻopili ʻia ʻo Nb4C3Tx MXene i nā cell microalgae (nā pahu polū ma Fig. 5a). ʻO ka mea nui, hiki i ka microalgae ke komo i nā metala e pili ana i ka neʻe ʻana o nā oxide metala ma ke kaiapuni67,68. Ua ʻike ʻo Shamshada et al.67 i ka emi ʻana o ka mana absorptive o nā algae wai maʻemaʻe me ka piʻi ʻana o ka pH. Ua ʻike ʻo Raize et al.68 he 25% kiʻekiʻe ke kiʻekiʻe o ka limu liʻiliʻi no ka Pb2+ ma mua o ka Ni2+.
(a) XRF hopena o basal Nb uptake e ka uliuli microalgae cell incubated ma kahi kiʻekiʻe loa o SL Nb-MXenes (100 mg L-1) no 72 hola. Hōʻike nā hopena i ka loaʻa ʻana o ka α i loko o nā pūnaewele microalgae maʻemaʻe (ka mana hoʻohālike, nā kolamu hina), 2D nanoflakes i hoʻokaʻawale ʻia mai ka ʻili microalgae cell (nā kolamu uliuli), a me nā cell microalgae ma hope o ke kaʻawale ʻana o nā nanoflakes 2D mai ka ʻili (nā kolamu ʻulaʻula). ʻO ka nui o ka elemental Nb, (b) pākēneka o ka haku mele mele microalgae nā mea ʻokoʻa (C=O a me CHx/C–O) a me Nb oxides i loaʻa i loko o nā pūnaewele microalgae ma hope o ka incubation me SL Nb-MXenes, (c–e) ʻO ka hoʻokomo ʻana i ka piko haku mele o XPS SL Nb2CTx spectra a me (fh) SLx Nb4CTx spectra a me (fh) SLx Nb4CTx spectra a me (fh) SLx Nb4CTx i loko.
No laila, ua manaʻo mākou e hiki ke hoʻopili ʻia ʻo Nb e nā cell algal ma ke ʻano o nā oxides. No ka ho'āʻoʻana i kēia, ua hana mākou i nā haʻawina XPS ma MXenes Nb2CTx a me Nb4C3TX a me nā pūnaewele algae. Hōʻike ʻia nā hopena o ka launa pū ʻana o nā microalgae me Nb-MXenes a me MXenes i hoʻokaʻawale ʻia mai nā cell algae ma Fig. 5b. E like me ka mea i manaʻo ʻia, ua ʻike mākou i nā piko Nb 3d i nā ʻano microalgae ma hope o ka wehe ʻana o MXene mai ka ʻili o ka microalgae. Ua heluʻia ka hoʻoholo nui o C = O, CHx / CO, a me Nb oxides ma muli o ka Nb 3d, O 1s, a me C 1s spectra i loaʻa me Nb2CTx SL (Fig. 5c-e) a me Nb4C3Tx SL (Fig. 5c-e). ) i loaʻa mai i nā microalgae i hoʻokomo ʻia. Kii 5f–h) MXenes. Hōʻike ka papa S1-3 i nā kikoʻī o nā ʻāpana kiʻekiʻe a me nā kemika holoʻokoʻa i loaʻa mai ke kūpono. He mea pono no ka Nb 3d māhele o Nb2CTx SL a me Nb4C3Tx SL (Fig. 5c, f) pili i hoʻokahi mea Nb2O5. Maʻaneʻi, ʻaʻole i loaʻa iā mākou nā piko pili i ka MXene i ka spectra, e hōʻike ana e komo wale nā ​​cell microalgae i ke ʻano oxide o Nb. Eia hou, ua hoʻopili mākou i ka spectrum C 1 me nā ʻāpana C–C, CHx/C–O, C=O, a me –COOH. Hāʻawi mākou i nā piko CHx/C–O a me C=O i ka hāʻawi organik o nā pūnaewele microalgae. He 36% a me 41% o na piko C 1s ma Nb2CTx SL a me Nb4C3TX SL no keia mau mea kino. A laila hoʻokomo mākou i ka spectra O 1s o SL Nb2CTx a me SL Nb4C3TX me Nb2O5, nā ʻāpana kūlohelohe o microalgae (CHx/CO), a me ka wai hoʻoheheʻe ʻia i luna.
ʻO ka mea hope loa, ua hōʻike maopopo ʻia nā hopena XPS i ke ʻano o Nb, ʻaʻole wale kona hele ʻana. Wahi a ke kūlana o ka hōʻailona Nb 3d a me nā hopena o ka deconvolution, hōʻoia mākou e komo wale ʻia ʻo Nb ma ke ʻano o nā oxides a ʻaʻole i nā ion a i ʻole MXene ponoʻī. Eia hou, ua hōʻike ʻia nā hopena XPS he ʻoi aku ka nui o nā cell microalgae e lawe i nā Nb oxides mai SL Nb2CTx i hoʻohālikelike ʻia me SL Nb4C3TX MXene.
ʻOiai he mea kupanaha kā mākou mau hopena Nb uptake a ʻae iā mākou e ʻike i ka hoʻohaʻahaʻa ʻana o MXene, ʻaʻohe ala i loaʻa e nānā i nā loli morphological pili i nā nanoflakes 2D. No laila, ua hoʻoholo pū mākou e hoʻomohala i kahi ala kūpono e hiki ke pane pololei i nā loli i hana ʻia ma 2D Nb-MXene nanoflakes a me nā cell microalgae. Pono mākou e hoʻomaopopo i ka manaʻo inā loaʻa ka hoʻololi, decomposition a defragmentation paha ka mea e pili ana, e hōʻike koke kēia iā ia iho ma ke ʻano he hoʻololi ʻana i nā ʻāpana ʻano, e like me ke anawaena o ka ʻāpana pōʻai like, ka pōʻai, ka laulā Feret, a i ʻole ka lōʻihi o Feret. No ka mea ua kūpono kēia mau ʻāpana no ka wehewehe ʻana i nā ʻāpana elongated a i ʻole nā ​​nanoflakes ʻelua-dimensional, ʻo kā lākou ʻimi ʻana ma ke ʻano o ka hoʻoheheʻe ʻana o ka particle dynamic e hāʻawi iā mākou i ka ʻike waiwai e pili ana i ka hoʻololi morphological o nā nanoflakes SL Nb-MXene i ka wā hōʻemi.
Hōʻike ʻia nā hopena i loaʻa ma ka Figure 6. No ka hoʻohālikelike ʻana, ua hoʻāʻo pū mākou i ka pae mua MAX a me ML-MXenes (e nānā i nā kiʻi SI S18 a me S19). Ua hōʻike ʻia ka hōʻike ʻana i ke ʻano o nā ʻano ʻāpana i nā ʻāpana ʻano āpau o ʻelua Nb-MXene SLs i loli nui ma hope o ka launa pū ʻana me microalgae. E like me ka mea i hōʻike ʻia e ka hoʻohālikelike ʻāpana ʻāpana pōʻai like (Fig. 6a, b), ʻo ka hōʻemi ʻana i ka ikaika kiʻekiʻe o ka hakina o nā nanoflakes nui e hōʻike ana e palaho lākou i nā ʻāpana liʻiliʻi. Ma ka fig. 6c, d e hōʻike ana i ka emi ʻana o nā piko e pili ana i ka nui transverse o nā flakes (elongation o nā nanoflakes), e hōʻike ana i ka hoʻololi ʻana o nā nanoflakes 2D i kahi ʻano like ʻole. Kii 6e-h e hoike ana i ka laula a me ka loa o ka Feret. ʻO ka laulā feret a me ka lōʻihi he mau ʻāpana hoʻohui a no laila pono e noʻonoʻo pū ʻia. Ma hope o ka incubation o 2D Nb-MXene nanoflakes i mua o ka microalgae, ua neʻe ko lākou Feret correlation peaks a emi ko lakou ikaika. Ma muli o kēia mau hopena i hui pū ʻia me ka morphology, XRF a me XPS, ua hoʻoholo mākou ua pili nui nā loli i ʻike ʻia i ka oxidation e like me ka oxidized MXenes e lilo i ʻoi aku ka wrinkled a wāwahi i nā ʻāpana a me nā ʻāpana spherical oxide69,70.
ʻIkepili o ka hoʻololi ʻana o MXene ma hope o ka launa pū ʻana me nā microalgae ʻōmaʻomaʻo. E noʻonoʻo ana ka nānā ʻana i ke ʻano o ke ʻano mea ʻala ikaika e like me (a, b) anawaena o ka ʻāpana pōʻai like, (c, d) pōʻai, (e, f) ākea Feret a me (g, h) lōʻihi Feret. No kēia hopena, ua kālailai ʻia nā laʻana microalgae ʻelua me SL Nb2CTx mua a me SL Nb4C3Tx MXenes, SL Nb2CTx a me SL Nb4C3Tx MXenes, microalgae degraded, a mālama ʻia nā microalgae SL Nb2CTx a me SL Nb4C3Tx MXenes. Hōʻike nā pua ʻulaʻula i ka hoʻololi ʻana o nā ʻāpana hoʻohālikelike o nā nanoflakes ʻelua-dimensional i aʻo ʻia.
Ma muli o ka hilinaʻi nui ʻana o ka nānā ʻana i nā ʻāpana hoʻohālikelike, hiki iā ia ke hōʻike i nā loli morphological i nā cell microalgae. No laila, ua kālailai mākou i ke anawaena āpana poʻai like, ka poepoe, a me ka laulā Feret / ka lōʻihi o nā pūnaewele microalgae maʻemaʻe a me nā pūnaewele ma hope o ka launa pū ʻana me 2D Nb nanoflakes. Ma ka fig. Hōʻike ʻo 6a–h i nā loli i ke ʻano o nā ʻāpana algae, e like me ka emi ʻana o ka ikaika kiʻekiʻe a me ka neʻe ʻana o ka maxima i nā waiwai kiʻekiʻe. ʻO ka mea nui, ua hōʻike ʻia nā ʻāpana pōʻai o ka cell i ka emi ʻana o nā cell elongated a me ka piʻi ʻana o nā cell spherical (Fig. 6a, b). Eia kekahi, ua hoʻonui ʻia ka laulā o Feret e kekahi mau micrometers ma hope o ka launa pū ʻana me SL Nb2CTx MXene (Fig. 6e) i hoʻohālikelike ʻia me SL Nb4C3TX MXene (Fig. 6f). Manaʻo mākou ma muli paha o ka lawe ikaika ʻana o Nb oxides e ka microalgae ma ka launa pū ʻana me Nb2CTx SR. ʻO ka hoʻopili liʻiliʻi liʻiliʻi o nā flakes Nb i ko lākou ili hiki ke hopena i ka ulu ʻana o ke kelepona me ka liʻiliʻi o ka hopena malu.
ʻO kā mākou nānā ʻana i nā loli i nā ʻāpana o ke ʻano a me ka nui o ka microalgae hoʻohui i nā haʻawina ʻē aʻe. Hiki i nā microalgae ʻōmaʻomaʻo ke hoʻololi i kā lākou morphology i ka pane ʻana i ke koʻikoʻi o ke kaiapuni ma o ka hoʻololi ʻana i ka nui o ke kelepona, ke ʻano a i ʻole ka metabolism61. No ka laʻana, ʻo ka hoʻololi ʻana i ka nui o nā cell e hoʻomaʻamaʻa i ka lawe ʻana i nā meaʻai71. Hōʻike ka liʻiliʻi liʻiliʻi liʻiliʻi i ka lawe ʻana i nā meaʻai a me ka piʻi ʻana o ka ulu. ʻO ka mea ʻē aʻe, ʻoi aku ka nui o nā cell i ka ʻai ʻana i nā meaʻai, a laila waiho ʻia intracellularly72,73. Ua ʻike ʻo Machado lāua ʻo Soares e hiki i ka fungicide triclosan ke hoʻonui i ka nui o ka cell. Ua ʻike pū lākou i nā loli nui i ke ʻano o ka algae74. Eia hou, ua hōʻike pū ʻo Yin et al.9 i nā loli morphological i loko o ka algae ma hope o ka hoʻolaha ʻana i nā nanocomposites graphene oxide i hoʻemi ʻia. No laila, ua maopopo ka hoʻololi ʻia o ka nui / ʻano ʻāpana o ka microalgae ma muli o ka hiki ʻana o MXene. No ka mea, ʻo kēia hoʻololi ʻana i ka nui a me ke ʻano he hōʻike ia i nā loli i ka lawe ʻana i ka meaʻai, manaʻo mākou ʻo ka nānā ʻana i ka nui a me nā ʻāpana hoʻohālikelike i ka manawa hiki ke hōʻike i ka lawe ʻana o ka niobium oxide e nā microalgae i mua o Nb-MXenes.
Eia kekahi, hiki ke hoʻokahe ʻia nā MXenes i mua o nā algae. Ua ʻike ʻo Dalai et al.75 ʻaʻole like ka morphology o nā limu ʻōmaʻomaʻo i hōʻike ʻia i nano-TiO2 a me Al2O376. ʻOiaiʻo kā mākou mauʻike e like me ka haʻawina o kēia manawa, pili wale ia i ke aʻoʻana i nā hopena o ka bioremediation e pili ana i nā huahana hoʻohaʻahaʻa MXene i mua o nā nanoflakes 2D aʻaʻole nā ​​nanoparticles. Ma muli o ka hiki i ka MXenes ke hoʻohaʻahaʻa i nā oxides metala, 31,32,77,78 he mea kūpono ke manaʻo e hiki i kā mākou Nb nanoflakes ke hana i nā Nb oxides ma hope o ka launa pū ʻana me nā cell microalgae.
I mea e wehewehe ai i ka emi ʻana o nā nanoflakes 2D-Nb ma o ka decomposition mechanism ma muli o ke kaʻina hana oxidation, ua hana mākou i nā haʻawina me ka hoʻohana ʻana i ka microscopy electron transmission kiʻekiʻe (HRTEM) (Fig. 7a, b) a me X-ray photoelectron spectroscopy (XPS) (Fig. 7). 7c-i a me nā papa S4-5). Ua kūpono nā ala ʻelua no ke aʻo ʻana i ka oxidation o nā mea 2D a hoʻokō kekahi i kekahi. Hiki i ka HRTEM ke kālailai i ka hoʻohaʻahaʻa ʻana o nā hale papa ʻelua-dimensional a me ka ʻike ʻana o nā nanoparticles metal oxide, ʻoiai ʻo XPS ka mea maʻalahi i nā mea paʻa i luna. No kēia kumu, ua hoʻāʻo mākou i nā nanoflakes 2D Nb-MXene i unuhi ʻia mai nā dispersion cell microalgae, ʻo ia hoʻi, ko lākou ʻano ma hope o ka launa pū ʻana me nā cell microalgae (e nānā i ka Fig. 7).
Nā kiʻi HRTEM e hōʻike ana i ka morphology o oxidized (a) SL Nb2CTx a me (b) SL Nb4C3Tx MXenes, XPS nā hualoaʻa hōʻike e hōʻike ana (c) ka hoʻohui ʻana o nā huahana oxide ma hope o ka hoʻemi ʻana, (d–f) hoʻohālikelike kiʻekiʻe o nā mea o ka spectra XPS o SL Nb2CTx a me (g– i) micro Nb4C3Tx ʻōmaʻomaʻo.
Ua hōʻoia nā haʻawina HRTEM i ka oxidation o ʻelua mau ʻano Nb-MXene nanoflakes. ʻOiai ua paʻa nā nanoflakes i kā lākou morphology ʻelua-dimensional i kekahi ʻano, ua hopena ka oxidation i ke ʻano o nā nanoparticles he nui e uhi ana i ka ʻili o nā nanoflakes MXene (e nānā i ka Fig. 7a,b). Hōʻike ka hōʻike XPS o nā hōʻailona c Nb 3d a me O 1s ua hoʻokumu ʻia nā Nb oxides ma nā hihia ʻelua. E like me ka mea i hōʻike ʻia ma ka Figure 7c, 2D MXene Nb2CTx a me Nb4C3TX nā hōʻailona Nb 3d e hōʻike ana i ke alo o NbO a me Nb2O5 oxides, ʻoiai nā hōʻailona O 1s e hōʻike i ka helu o nā mea paʻa O-Nb e pili ana me ka functionalization o ka ili nanoflake 2D. Ua ʻike mākou i ka nui o ka hāʻawi ʻana o Nb oxide i hoʻohālikelike ʻia me Nb-C a me Nb3+-O.
Ma ka fig. Hōʻike nā kiʻi 7g–i i ke kikoʻī XPS o Nb 3d, C 1s, a me O 1s SL Nb2CTx (e ʻike i nā kiʻi 7d–f) a me SL Nb4C3TX MXene i hoʻokaʻawale ʻia mai nā cell microalgae. Hāʻawi ʻia nā kikoʻī o nā ʻāpana kiʻekiʻe o Nb-MXenes ma nā Papa S4-5. Ua nānā mua mākou i ka haku ʻana o Nb 3d. He ʻokoʻa me ka Nb i hoʻomoʻa ʻia e nā pūnaewele microalgae, ma MXene i hoʻokaʻawale ʻia mai nā cell microalgae, ma waho o Nb2O5, ua loaʻa nā mea ʻē aʻe. Ma ka Nb2CTx SL, ua ʻike mākou i ka hāʻawi ʻana o Nb3 + -O i ka nui o 15%, aʻo ke koena o ka spectrum Nb 3d i hoʻomalu ʻia e Nb2O5 (85%). Eia kekahi, ʻo ka laʻana SL Nb4C3TX nā mea Nb-C (9%) a me Nb2O5 (91%). Eia ʻo Nb-C mai ʻelua mau ʻāpana atomika i loko o ka carbide metala ma Nb4C3Tx SR. A laila palapala mākou i ka spectra C 1s i ʻehā mau ʻāpana like ʻole, e like me kā mākou i hana ai i nā laʻana i loko. E like me ka mea i manaʻo ʻia, ua hoʻomalu ʻia ka spectrum C 1s e ka carbon graphitic, a ukali ʻia e nā haʻawina mai nā ʻāpana organik (CHx/CO a me C=O) mai nā cell microalgae. Eia kekahi, ma ka spectrum O 1s, ua nānā mākou i ka hāʻawi ʻana o nā ʻano mea ola o nā ʻāpana microalgae, niobium oxide, a me ka wai adsorbed.
Eia hou, ua noiʻi mākou inā pili ʻo Nb-MXenes cleavage me ka loaʻa ʻana o nā ʻano oxygen reactive (ROS) i loko o ka meaʻai meaʻai a / a i ʻole nā ​​​​pūnaewele microalgae. No kēia hopena, ua loiloi mākou i nā pae o ka oxygen singlet (1O2) i loko o ka moʻomeheu moʻomeheu a me ka glutathione intracellular, he thiol e hana ana ma ke ʻano he antioxidant i nā microalgae. Hōʻike ʻia nā hopena ma SI (Nā Kiʻi S20 a me S21). ʻO nā moʻomeheu me SL Nb2CTx a me Nb4C3TX MXenes i hōʻike ʻia e kahi hōʻemi o 1O2 (e ʻike i ke Kiʻi S20). I ka hihia o SL Nb2CTx, MXene 1O2 ua ho'ēmiʻia ma kahi o 83%. No nā moʻomeheu microalgae e hoʻohana ana i ka SL, Nb4C3TX 1O2 i hōʻemi hou aʻe, i 73%. ʻO ka mea e mahalo ai, ua hōʻike nā hoʻololi i ka 1O2 i ke ʻano like me ka hopena inhibitory-stimulatory i ʻike mua ʻia (e nānā i ka Fig. 3). Hiki ke hoʻopaʻapaʻa ʻia hiki ke hoʻololi i ka incubation i ka mālamalama mālamalama i ka photooxidation. Eia naʻe, ua hōʻike ʻia nā hopena o ka nānā ʻana o ka mana i nā pae mau o 1O2 i ka wā o ka hoʻokolohua (Fig. S22). I ka hihia o nā pae ROS intracellular, ua ʻike pū mākou i ke ʻano iho i lalo (e nānā i ke kiʻi S21). I ka hoʻomaka ʻana, ʻoi aku ka nui o nā pae o ROS i loko o nā cell microalgae i hoʻolaʻa ʻia ma ke alo o Nb2CTx a me Nb4C3Tx SLs ma mua o nā pae i loaʻa i nā moʻomeheu maʻemaʻe o microalgae. I ka hopena, akā naʻe, ua ʻike ʻia ua hoʻololi ʻia ka microalgae i ke alo o nā Nb-MXenes ʻelua, ʻoiai ua emi nā pae ROS i 85% a me 91% o nā pae i ana ʻia i nā moʻomeheu maʻemaʻe o nā microalgae i hoʻopaʻa ʻia me SL Nb2CTx a me Nb4C3TX, kēlā me kēia. Hōʻike paha kēia i ka ʻoluʻolu o ka microalgae i ka manawa ma mua o ka Nb-MXene ma mua o ka ʻano meaʻai wale nō.
ʻO Microalgae kahi hui like ʻole o nā mea ola photosynthetic. I ka wā photosynthesis, hoʻololi lākou i ka carbon dioxide (CO2) i loko o ke kalapona organik. ʻO nā huahana o ka photosynthesis ka glucose a me ka oxygen79. Ke manaʻo nei mākou he hana koʻikoʻi ka oxygen i hana ʻia i ka oxidation o Nb-MXenes. ʻO kekahi wehewehe ʻana no kēia, ʻo ia ka hoʻokumu ʻana o ka ʻokoʻa ʻokoʻa ma nā ʻāpana haʻahaʻa a kiʻekiʻe o ka oxygen ma waho a i loko o nā nanoflakes Nb-MXene. ʻO ia hoʻi, ma nā wahi āpau o nā ʻāpana ʻāpana like ʻole o ka oxygen, ʻo ka wahi me ka pae haʻahaʻa e hana i ka anode 80, 81, 82. Ma ʻaneʻi, hāʻawi ka microalgae i ka hana ʻana o nā cell aerated differentially ma ka ʻili o nā flakes MXene, e hoʻopuka ana i ka oxygen ma muli o kā lākou mau waiwai photosynthetic. ʻO ka hopena, ua hoʻokumu ʻia nā huahana biocorrosion (i kēia hihia, niobium oxides). ʻO kekahi hiʻohiʻona ʻo ia ka hiki i ka microalgae ke hoʻohua i nā waikawa organik i hoʻokuʻu ʻia i loko o ka wai83,84. No laila, ua hoʻokumu ʻia kahi ʻano koʻikoʻi, a laila hoʻololi i ka Nb-MXenes. Eia hou, hiki i ka microalgae ke hoʻololi i ka pH o ke kaiapuni i ka alkaline ma muli o ke komo ʻana o ka carbon dioxide, hiki ke hoʻoulu i ka corrosion79.
ʻO ka mea nui, ʻo ka photoperiod pōʻeleʻele / māmā i hoʻohana ʻia i kā mākou aʻo ʻana he mea koʻikoʻi i ka hoʻomaopopo ʻana i nā hopena i loaʻa. Ua wehewehe nui ʻia kēia ʻano ma Djemai-Zoghlache et al. 85 Ua hoʻohana lākou i ka manawa kiʻi 12/12 hola e hōʻike i ka biocorrosion e pili ana i ka biofouling e ka microalgae ʻulaʻula Porphyridium purpureum. Hōʻike lākou e pili ana ka photoperiod me ka ulu ʻana o ka hiki me ka ʻole biocorrosion, e hōʻike ana iā ia iho he pseudoperiodic oscillations a puni 24:00. Ua hōʻoia ʻia kēia mau ʻike e Dowling et al. 86 Ua hōʻike lākou i nā biofilm photosynthetic o cyanobacteria Anabaena. Hoʻokumu ʻia ka oxygen i hoʻoheheʻe ʻia ma lalo o ka hana o ka mālamalama, e pili ana me ka hoʻololi a i ʻole ka fluctuations i ka hiki ke biocorrosion manuahi. ʻO ke koʻikoʻi o ka photoperiod e hoʻokūpaʻa ʻia e ka ʻoiaʻiʻo e piʻi ka manuahi manuahi no ka biocorrosion i ka pae māmā a emi iho i ka manawa pōʻeleʻele. Ma muli o ka oxygen i hana ʻia e nā microalgae photosynthetic, ka mea e hoʻoikaika i ka hopena cathodic ma o ke kaomi ʻāpana i hana ʻia ma kahi kokoke i nā electrodes87.
Eia hou, ua hana ʻia ʻo Fourier transform infrared spectroscopy (FTIR) no ka ʻike ʻana inā loaʻa kekahi mau hoʻololi i ka hoʻohui kemika o nā cell microalgae ma hope o ka launa pū ʻana me Nb-MXenes. He paʻakikī kēia mau hopena i loaʻa a hōʻike mākou iā lākou ma SI (Nā Kiʻi S23-S25, me nā hopena o ka pae MAX a me ML MXenes). I ka pōkole, hāʻawi ka ʻike kikoʻī o microalgae iā mākou i ka ʻike koʻikoʻi e pili ana i nā ʻano kemika o kēia mau mea ola. Aia kēia mau haʻalulu nui loa ma nā alapine o 1060 cm-1 (CO), 1540 cm-1, 1640 cm-1 (C=C), 1730 cm-1 (C=O), 2850 cm-1, 2920 cm-1. ʻekahi. 1 1 (C–H) a me 3280 knm–1 (O–H). No SL Nb-MXenes, ua loaʻa iā mākou kahi pūlima hohola CH-bond i kūlike me kā mākou haʻawina mua38. Eia nō naʻe, ʻike mākou ua nalowale kekahi mau kiʻekiʻe e pili ana me nā paʻa C = C a me CH. Hōʻike kēia i ka hiki ke hoʻololi liʻiliʻi ka haku mele ʻana o ka microalgae ma muli o ka launa pū ʻana me SL Nb-MXenes.
I ka noʻonoʻo ʻana i nā loli hiki ke hiki i ka biochemistry o nā microalgae, pono e noʻonoʻo hou ʻia ka hōʻiliʻili ʻana o nā oxide inorganic, e like me ka niobium oxide. Hoʻopili ia i ka lawe ʻana o nā metala e ka ʻili o ke kelepona, kā lākou lawe ʻana i ka cytoplasm, kā lākou hui ʻana me nā hui carboxyl intracellular, a me kā lākou hōʻiliʻili ʻana i nā microalgae polyphosphosomes20,88,89,90. Eia kekahi, mālama ʻia ka pilina ma waena o nā microalgae a me nā metala e nā pūʻulu hana o nā cell. No kēia kumu, pili pū ka absorption i ka microalgae surface chemistry, he paʻakikī loa ia9,91. Ma keʻano laulā, e like me ka mea i manaʻo ʻia, ua hoʻololi iki ke ʻano kemika o nā microalgae ʻōmaʻomaʻo ma muli o ka absorption o Nb oxide.
ʻO ka mea e mahalo ai, hiki ke hoʻohuli ʻia ka pale mua ʻana o ka microalgae i ka manawa. E like me kā mākou i ʻike ai, ua lanakila ka microalgae i ka hoʻololi ʻana o ke kaiapuni mua a hoʻi hou i ka ulu maʻamau a hoʻonui aʻe. Hōʻike nā haʻawina o ka zeta hiki ke kūpaʻa i ka wā i hoʻokomo ʻia i loko o ka media nutrient. No laila, mālama ʻia ka pilina ma waena o nā microalgae cell a me Nb-MXene nanoflakes i nā hoʻokolohua hoʻemi. I kā mākou ʻimi hou aʻe, hōʻuluʻulu mākou i nā hana nui o ka hana i lalo o kēia ʻano kupaianaha o ka microalgae.
Ua hōʻike ʻia nā ʻike SEM e pili ana nā microalgae i Nb-MXenes. Ke hoʻohana nei i ka nānā ʻana i nā kiʻi hoʻoikaika, hōʻoia mākou e alakaʻi kēia hopena i ka hoʻololi ʻana o nā nanoflakes Nb-MXene ʻelua i loko o nā ʻāpana spherical hou aʻe, e hōʻike ana i ka pili ʻana o ka decomposition o nā nanoflakes me kā lākou oxidation. No ka hoʻāʻo ʻana i kā mākou kuhiakau, ua hana mākou i kahi ʻano o nā haʻawina a me nā haʻawina biochemical. Ma hope o ka hoʻāʻo ʻana, ua hoʻoheheʻe ʻia nā nanoflakes i loko o nā huahana NbO a me Nb2O5, ʻaʻole i hoʻoweliweli i nā microalgae ʻōmaʻomaʻo. Ke hoʻohana nei i ka nānā ʻana iā FTIR, ʻaʻole mākou i ʻike i nā loli koʻikoʻi i ka haku melemele o nā microalgae i hoʻomoʻa ʻia i mua o nā nanoflakes 2D Nb-MXene. No ka noʻonoʻo ʻana i ka hiki ke komo ʻana o ka niobium oxide e ka microalgae, ua hana mākou i kahi loiloi fluorescence X-ray. Hōʻike maopopo kēia mau hopena i ka ʻai ʻana o nā microalgae i aʻo ʻia i nā niobium oxides (NbO a me Nb2O5), ʻaʻohe mea ʻona i ka microalgae i aʻo ʻia.