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Kulo msebenzi, izinhlanganisela ze-rGO/nZVI zahlanganiswa okokuqala ngqa kusetshenziswa inqubo elula neyobungani nemvelo kusetshenziswa i-Sophora yeqabunga eliphuzi njenge-ejenti yokunciphisa kanye ne-stabilizer ukuze kuhambisane nemigomo ye-chemistry "eluhlaza", njengokwenziwa kwamakhemikhali okungenangozi kakhulu. Amathuluzi amaningana asetshenziswe ukuqinisekisa ukwenziwa okuphumelelayo kwezinhlanganisela, njenge-SEM, EDX, XPS, XRD, FTIR, kanye ne-zeta potential, okubonisa ukwenziwa okuphumelelayo kwenhlanganisela. Amandla okususa izinhlanganisela ezintsha kanye ne-nZVI emsulwa ekugxilweni okuhlukahlukene kokuqala kwe-antibiotic doxycycline aqhathaniswa ukuze kuhlolwe umphumela wokubambisana phakathi kwe-rGO ne-nZVI. Ngaphansi kwezimo zokususa ze-25mg L-1, 25°C kanye ne-0.05g, izinga lokususa i-nZVI emsulwa lalingu-90%, kanti izinga lokususa i-doxycycline nge-composite ye-rGO/nZVI lifinyelele ku-94.6%, okuqinisekisa ukuthi i-nZVI ne-rGO. Inqubo yokumunca ihambisana nohlelo lwesibili futhi ivumelana kahle nemodeli ye-Freundlich enekhono eliphezulu lokumunca elingu-31.61 mg g-1 ku-25 °C kanye ne-pH 7. Kuphakanyiswe indlela efanelekile yokususa i-DC. Ngaphezu kwalokho, ukusetshenziswa kabusha kwenhlanganisela ye-rGO/nZVI kwaba ngu-60% ngemuva kwemijikelezo eyisithupha elandelanayo yokuvuselelwa.
Ukuntuleka kwamanzi kanye nokungcola kwamanzi manje sekuwusongo olukhulu kuwo wonke amazwe. Eminyakeni yamuva nje, ukungcola kwamanzi, ikakhulukazi ukungcola kwama-antibiotic, kuye kwanda ngenxa yokwanda kokukhiqizwa nokusetshenziswa ngesikhathi sobhubhane lwe-COVID-191,2,3. Ngakho-ke, ukuthuthukiswa kobuchwepheshe obusebenzayo bokuqeda ama-antibiotic emanzini angcolile kuwumsebenzi ophuthumayo.
Enye yama-antibiotic amelana nokwakheka kwe-semi-synthetic avela eqenjini le-tetracycline yi-doxycycline (DC)4,5. Kubikwe ukuthi izinsalela ze-DC emanzini angaphansi komhlaba nasemanzini angaphezulu azikwazi ukwakheka, yi-20-50% kuphela eguqulwa ibe yi-metabolite kanti okusele kukhishwa emvelweni, okubangela izinkinga ezinkulu zemvelo nezempilo6.
Ukuchayeka ku-DC emazingeni aphansi kungabulala ama-microorganism asemanzini akhiqiza i-photosynthesis, kusongela ukusabalala kwamagciwane alwa namagciwane, futhi kwandise ukumelana namagciwane, ngakho-ke lokhu kungcola kumele kususwe emanzini angcolile. Ukuwohloka kwemvelo kwe-DC emanzini kuyinqubo ehamba kancane kakhulu. Izinqubo ze-physico-chemical ezifana ne-photolysis, i-biodegradation kanye ne-adsorption zingonakala kuphela ngamanani aphansi futhi ngamanani aphansi kakhulu7,8. Kodwa-ke, indlela engabizi kakhulu, elula, enobungani nemvelo, elula ukuyiphatha futhi ephumelelayo yi-adsorption9,10.
I-Nano zero valent iron (nZVI) iyinto enamandla kakhulu engasusa ama-antibiotic amaningi emanzini, okuhlanganisa i-metronidazole, i-diazepam, i-ciprofloxacin, i-chloramphenicol, kanye ne-tetracycline. Leli khono libangelwa yizakhiwo ezimangalisayo i-nZVI enazo, njengokusabela okuphezulu, indawo enkulu, kanye nezindawo eziningi zokubopha zangaphandle11. Kodwa-ke, i-nZVI ivame ukuhlangana emanzini ngenxa yamandla e-van der Wells kanye nezakhiwo eziphezulu zamagnetic, okunciphisa ukusebenza kwayo ekususeni ukungcola ngenxa yokwakheka kwezingqimba ze-oxide ezivimbela ukusabela kwe-nZVI10,12. Ukuhlangana kwezinhlayiya ze-nZVI kungancishiswa ngokushintsha izindawo zazo ngama-surfactants nama-polymer noma ngokuzihlanganisa nezinye izinto ze-nanomaterials ngesimo sezinhlanganisela, okuye kwabonakala kuyindlela ephumelelayo yokuthuthukisa ukuzinza kwazo emvelweni13,14.
I-Graphene iyi-nanomaterial yekhabhoni enezinhlangothi ezimbili equkethe ama-athomu ekhabhoni ahlanganisiwe e-sp2 ahlelwe ku-lattice yezinyosi. Inendawo enkulu ebusweni, amandla amakhulu okusebenza, umsebenzi omuhle kakhulu we-electrocatalytic, ukuhanjiswa kokushisa okuphezulu, ukuhamba okusheshayo kwama-electron, kanye nezinto zokuthwala ezifanele ukusekela ama-nanoparticles angaphili ebusweni bayo. Ukuhlanganiswa kwama-nanoparticles ensimbi kanye ne-graphene kungadlula kakhulu izinzuzo zomuntu ngamunye zezinto ngayinye futhi, ngenxa yezakhiwo zayo eziphakeme zomzimba nezamakhemikhali, kuhlinzeka ngokusatshalaliswa okuhle kwama-nanoparticles ukuze kusetshenziswe kahle amanzi15.
Izithako zezitshalo ziyindlela engcono kakhulu yokukhetha ama-agent anciphisa amakhemikhali ayingozi avame ukusetshenziswa ekwakhiweni kwe-graphene oxide encishisiwe (rGO) kanye ne-nZVI ngoba ayatholakala, ashibhile, asebenza ngesinyathelo esisodwa, aphephile emvelweni, futhi angasetshenziswa njenge-agent yokunciphisa. njenge-flavonoids kanye nama-phenolic compounds nawo asebenza njengesiqinisi. Ngakho-ke, i-Atriplex halimus L. leaf extract yasetshenziswa njenge-ejenti yokulungisa nokuvala yokwenziwa kwezinhlanganisela ze-rGO/nZVI kulolu cwaningo. I-Atriplex halimus evela emndenini i-Amaranthaceae iyisihlahla esihlala isikhathi eside esithanda i-nitrogen esinobubanzi bezindawo16.
Ngokusho kwezincwadi ezitholakalayo, i-Atriplex halimus (A. halimus) yaqala ukusetshenziswa ukwenza izinhlanganisela ze-rGO/nZVI njengendlela yokwenza engabizi futhi enobungani nemvelo. Ngakho-ke, inhloso yalo msebenzi inezingxenye ezine: (1) i-phytosynthesis ye-rGO/nZVI kanye nezinhlanganisela ze-nZVI zabazali kusetshenziswa i-A. halimus amaqabunga angaphansi kwamanzi, (2) ukuchaza izinhlanganisela ezenziwe nge-phytosynthesis kusetshenziswa izindlela eziningi ukuqinisekisa ukwenziwa kwazo okuphumelelayo, (3) ukufunda umphumela wokubambisana we-rGO kanye ne-nZVI ekufakweni nasekususweni kokungcola okungokwemvelo kwama-antibiotic e-doxycycline ngaphansi kwemingcele ehlukene yokusabela, ukwenza ngcono izimo zenqubo yokufakweni, (3) ukuphenya izinto ezihlanganisiwe ekwelashweni okuhlukahlukene okuqhubekayo ngemva komjikelezo wokucubungula.
I-Doxycycline hydrochloride (DC, MM = 480.90, ifomula yamakhemikhali C22H24N2O·HCl, 98%), i-iron chloride hexahydrate (FeCl3.6H2O, 97%), i-graphite powder ethengwe kwa-Sigma-Aldrich, e-USA. I-Sodium hydroxide (NaOH, 97%), i-ethanol (C2H5OH, 99.9%) kanye ne-hydrochloric acid (HCl, 37%) ithengwe kwa-Merck, e-USA. I-NaCl, KCl, CaCl2, MnCl2 kanye ne-MgCl2 ithengwe kwa-Tianjin Comio Chemical Reagent Co., Ltd. Zonke izithasiselo zihlanzekile kakhulu. Amanzi axutshwe kabili asetshenziswa ukulungiselela zonke izixazululo zamanzi.
Izibonelo ezimele ze-A. halimus ziqoqwe endaweni yazo yemvelo eNile Delta futhi zitholakala ogwini lwaseMedithera lwaseGibhithe. Izinto zezitshalo ziqoqwe ngokuhambisana neziqondiso ezisebenzayo zikazwelonke nezamazwe ngamazwe17. USolwazi Manal Fawzi uhlonze izinhlobo zezitshalo ngokusho kweBoulos18, kanti uMnyango Wezesayensi Yezemvelo wase-Alexandria University ugunyaza ukuqoqwa kwezinhlobo zezitshalo ezifundwe ngezinjongo zesayensi. Izibonelo ze-voucher zigcinwe eTanta University Herbarium (TANE), i-voucher nos. 14 122–14 127, indawo yomphakathi enikeza ukufinyelela ezintweni ezigciniwe. Ngaphezu kwalokho, ukuze kususwe uthuli noma ukungcola, sika amaqabunga esitshalo abe yizicucu ezincane, ugeze izikhathi ezintathu ngompompi namanzi acwengekile, bese womisa ku-50°C. Isitshalo sachotshozwa, amagremu ama-5 empuphu ecolekileyo acwiliswa ku-100 ml wamanzi acwengekile futhi avuselelwa ku-70°C imizuzu engama-20 ukuze kutholakale i-extract. I-extract etholwe yi-Bacillus nicotianae yahlungwa ngephepha lokuhlunga le-Whatman futhi yagcinwa emapayipini ahlanzekile nahlanziwe ku-4°C ukuze isetshenziswe kabanzi.
Njengoba kuboniswe kuMfanekiso 1, i-GO yenziwe ngempuphu ye-graphite ngendlela ye-Hummers eguquliwe. I-10 mg yempuphu ye-GO yahlakazwa ku-50 ml wamanzi acwengekile imizuzu engama-30 ngaphansi kwe-sonication, bese kuthi i-0.9 g ye-FeCl3 kanye ne-2.9 g ye-NaAc zixutshwe imizuzu engama-60. I-20 ml ye-atriplex leaf extract yengezwe esixazululweni esivuselelwe ngokuxubha bese ishiywa ku-80°C amahora ayi-8. Ukumiswa okumnyama okubangelwe kwahlungwa. Ama-nanocomposites alungisiwe ahlanzwa nge-ethanol namanzi acwengekile abese omiswa kuhhavini we-vacuum ku-50°C amahora ayi-12.
Izithombe ezihleliwe nezedijithali zokwenziwa okuluhlaza kwe-rGO/nZVI kanye ne-nZVI complexes kanye nokususwa kwama-antibiotic e-DC emanzini angcolile kusetshenziswa i-Atriplex halimus extract.
Kafushane, njengoba kuboniswe ku-Fig. 1, i-10 ml yesisombululo se-iron chloride equkethe ama-ion angu-0.05 M Fe3+ yengezwe ngokuwa phansi ku-20 ml yesisombululo se-bitter leaf extract imizuzu engama-60 ngokushisa okuphakathi nokuxubha, bese isixazululo sabe sesifakwa ku-centrifuge ku-14,000 rpm (Hermle, 15,000 rpm) imizuzu eyi-15 ukuze kunikezwe izinhlayiya ezimnyama, ezabe sezigezwa izikhathi ezintathu nge-ethanol namanzi acwengekile bese zomiswa kuhhavini we-vacuum ku-60° C. ubusuku bonke.
Ama-composite e-rGO/nZVI kanye ne-nZVI ahlanganiswe yizitshalo abonakala nge-UV-visible spectroscopy (ama-spectrophotometer e-T70/T80 series UV/Vis, PG Instruments Ltd, UK) ebangeni lokuskena elingu-200-800 nm. Ukuze kuhlaziywe i-topography kanye nokusatshalaliswa kosayizi kwama-composite e-rGO/nZVI kanye ne-nZVI, kusetshenziswe i-TEM spectroscopy (JOEL, JEM-2100F, Japan, i-voltage esheshisayo engu-200 kV). Ukuze kuhlolwe amaqembu asebenzayo angabandakanyeka kuma-extract ezitshalo anesibopho senqubo yokutakula kanye nokuzinzisa, kwenziwa i-spectroscopy ye-FT-IR (i-JASCO spectrometer ebangeni elingu-4000-600 cm-1). Ngaphezu kwalokho, kusetshenziswe i-zeta potential analyzer (i-Zetasizer Nano ZS Malvern) ukuze kufundwe i-surface charge yama-nanomaterials ahlanganisiwe. Ekulinganisweni kwe-X-ray diffraction yezinto ezisetshenziswayo ezimpushana, kwasetshenziswa i-X-ray diffractometer (X'PERT PRO, eNetherlands), esebenza ngogesi (40 mA), i-voltage (45 kV) kububanzi be-2θ kusukela ku-20° kuya ku-80° kanye nemisebe ye-CuKa1 (\(\lambda =\ ) 1.54056 Ao). I-energy dispersive X-ray spectrometer (EDX) (imodeli i-JEOL JSM-IT100) yayinesibopho sokutadisha ukwakheka kwezinto eziyisisekelo lapho iqoqa i-Al K-α monochromatic X-rays kusukela ku--10 kuya ku-1350 eV ku-XPS, usayizi we-spot 400 μm K-ALPHA (Thermo Fisher Scientific, USA) amandla okudlulisa e-full spectrum angama-200 eV kanti i-narrow spectrum ingu-50 eV. Isampula ye-powder icindezelwa esibambi sesampula, esibekwa ekamelweni le-vacuum. I-spectrum ye-C1 s isetshenziswe njengereferensi ku-284.58 eV ukuthola amandla okubopha.
Ukuhlolwa kokumunca kwenziwa ukuze kuhlolwe ukusebenza kahle kwama-nanocomposites e-rGO/nZVI ahlanganisiwe ekususeni i-doxycycline (DC) ezixazululweni zamanzi. Ukuhlolwa kokumunca kwenziwa kuma-flasks e-Erlenmeyer angu-25 ml ngesivinini sokunyakazisa esingu-200 rpm ku-orbital shaker (Stuart, Orbital Shaker/SSL1) ku-298 K. Ngokuxuba isixazululo se-DC stock (1000 ppm) ngamanzi axutshwe ne-bidistilled. Ukuze kuhlolwe umphumela wesilinganiso se-rGO/nSVI ekusebenzeni kahle kokumunca, ama-nanocomposites anesisindo esihlukene (0.01–0.07 g) angezwe ku-20 ml wesisombululo se-DC. Ukuze kufundwe ama-kinetics kanye nama-isotherms okumunca, i-0.05 g ye-adsorbent yacwiliswa kusisombululo samanzi se-CD ngokuhlushwa kokuqala (25–100 mg L–1). Umphumela we-pH ekususweni kwe-DC wafundwa ku-pH (3–11) kanye nokuhlushwa kokuqala okungu-50 mg L-1 ku-25°C. Lungisa i-pH yesistimu ngokungeza inani elincane lesisombululo se-HCl noma se-NaOH (imitha ye-pH ye-Crison, imitha ye-pH, i-pH 25). Ngaphezu kwalokho, kuhlolwe ithonya lokushisa lokusabela ekuhlolweni kokumuncwa okusebangeni elingu-25-55°C. Umphumela wamandla e-ionic enkambisweni yokumuncwa wafundwa ngokungeza ukuhlushwa okuhlukahlukene kwe-NaCl (0.01–4 mol L–1) ekuhlushweni kokuqala okungu-50 mg L–1, pH 3 no-7), 25°C, kanye nomthamo wokumuncwa ongu-0.05 g. Ukumuncwa kwe-DC engamuncwanga kwalinganiswa kusetshenziswa i-dual beam UV-Vis spectrophotometer (T70/T80 series, PG Instruments Ltd, UK) ehlonyiswe ngama-quartz cuvettes angu-1.0 cm ubude bendlela kuma-wavelength aphezulu (λmax) angu-270 no-350 nm. Ukususwa kwephesenti lama-antibiotic e-DC (R%; Eq. 1) kanye nenani lokumuncwa kwe-DC, qt, Eq. 2 (mg/g) kwalinganiswa kusetshenziswa i-equation elandelayo.
lapho i-%R ingumthamo wokususa i-DC (%), i-Co ingukuhlushwa kwe-DC kokuqala ngesikhathi esingu-0, kanti i-C ingukuhlushwa kwe-DC ngesikhathi esingu-t, ngokulandelana (mg L-1).
lapho i-qe iyinani le-DC elifakwe i-adsorbent ngeyunithi ngayinye ye-adsorbent (mg g-1), i-Co kanye ne-Ce yizingqimba ngesikhathi se-zero kanye ne-equilibrium, ngokulandelana (mg l-1), i-V yivolumu yesisombululo (l), kanti i-m iyi-reagent ye-adsorption mass (g).
Izithombe ze-SEM (Izithombe 2A–C) zibonisa ukuma kwe-lamellar kwenhlanganisela ye-rGO/nZVI enezinhlayiya zensimbi eziyindilinga ezihlakazeke ngokulinganayo ebusweni bayo, okubonisa ukunamathela okuphumelelayo kwe-nZVI NPs ebusweni be-rGO. Ngaphezu kwalokho, kunezinhlayiya ezithile eqabungeni le-rGO, okuqinisekisa ukususwa kwamaqembu aqukethe umoya-mpilo kanye nokubuyiselwa kwe-A. halimus GO. Lezi zinhlayiya ezinkulu zisebenza njengezindawo zokulayisha okusebenzayo kwe-iron NPs. Izithombe ze-nZVI (Isithombe 2D-F) zibonise ukuthi ama-NP ensimbi ayindilinga ayehlakazeke kakhulu futhi awahlangananga, okubangelwa uhlobo lokumboza kwezingxenye zezitshalo zesitshalo esikhishwe. Usayizi wezinhlayiya wawuhluka ngaphakathi kuka-15–26 nm. Kodwa-ke, ezinye izifunda zinokuma kwe-mesoporous okunesakhiwo samaqhubu kanye nezimbobo, okunganikeza amandla aphezulu okumunca i-nZVI, ngoba angandisa amathuba okubamba ama-molecule e-DC ebusweni be-nZVI. Lapho kusetshenziswa i-Rosa Damascus extract ekwenzeni i-nZVI, ama-NP atholiwe ayengafani, enezikhala kanye nezimo ezahlukene, okwehlisa ukusebenza kwawo kahle ekufakweni kwe-Cr(VI) futhi kwandise isikhathi sokuphendula 23. Imiphumela ihambisana ne-nZVI eyenziwe ngamaqabunga e-oki kanye ne-mulberry, okuyizinhlayiya ezincane eziyindilinga ezinobukhulu obuhlukahlukene be-nanometer ngaphandle kokuhlangana okusobala.
Izithombe ze-SEM ze-rGO/nZVI (AC), i-nZVI (D, E) composites kanye namaphethini e-EDX e-nZVI/rGO (G) kanye ne-nZVI (H) composites.
Ukwakheka kwezinto eziyisisekelo ze-rGO/nZVI kanye ne-nZVI ezakhiwe ngezitshalo kufundwe kusetshenziswa i-EDX (Isithombe 2G, H). Izifundo zibonisa ukuthi i-nZVI yakhiwe yi-carbon (38.29% ngobuningi), i-oxygen (47.41% ngobuningi) kanye ne-iron (11.84% ngobuningi), kodwa nezinye izinto ezifana ne-phosphorus24 nazo zikhona, ezingatholakala ezikhishweni zezitshalo. Ngaphezu kwalokho, iphesenti eliphezulu le-carbon kanye ne-oxygen libangelwa ukuba khona kwama-phytochemicals avela ezikhishweni zezitshalo kumasampula e-nZVI angaphansi komhlaba. Lezi zinto zisatshalaliswa ngokulinganayo ku-rGO kodwa ngezilinganiso ezahlukene: C (39.16 wt %), O (46.98 wt %) kanye ne-Fe (10.99 wt %), i-EDX rGO/nZVI iphinde ikhombise ukuthi kukhona ezinye izinto ezifana ne-S, ezingahlotshaniswa nezikhishwe zezitshalo, ezisetshenziswayo. Isilinganiso samanje se-C:O kanye nokuqukethwe kwensimbi ku-composite ye-rGO/nZVI kusetshenziswa i-A. halimus kungcono kakhulu kunokusebenzisa i-extract yamaqabunga e-eucalyptus, njengoba ichaza ukwakheka kwe-C (23.44 wt.%), i-O (68.29 wt.% ) kanye ne-Fe (8.27 wt.%). wt %) 25. UNataša et al., 2022 babike ukwakheka okufanayo kwe-nZVI okwenziwe ngamaqabunga e-oki ne-mulberry futhi baqinisekisa ukuthi amaqembu e-polyphenol kanye namanye ama-molecule aqukethwe ku-extract yamaqabunga anesibopho senqubo yokunciphisa.
Ukwakheka kwe-nZVI okwenziwe ezitshalweni (Isithombe S2A, B) kwakuyindilinga futhi kungajwayelekile ngokwengxenye, ngobukhulu bezinhlayiya obumaphakathi obungu-23.09 ± 3.54 nm, noma kunjalo, ama-chain aggregates abonwe ngenxa yamandla e-van der Waals kanye ne-ferromagnetism. Lesi simo sezinhlayiya ezinamaqabunga amaningi kanye neziyindilinga sivumelana kahle nemiphumela ye-SEM. Ukuqaphela okufanayo kwatholakala ngu-Abdelfatah et al. ngo-2021 lapho kusetshenziswa i-castor bean leaf extract ekwakhiweni kwe-nZVI11. I-Ruelas tuberosa leaf extract NPs esetshenziswa njenge-reducing agent ku-nZVI nayo inomumo oyindilinga onobubanzi obungu-20 kuya ku-40 nm26.
Izithombe ze-hybrid rGO/nZVI composite TEM (Umfanekiso S2C-D) zibonise ukuthi i-rGO iyindiza eyisisekelo enemigoqo esemaphethelweni kanye nemibimbi enikeza izindawo eziningi zokulayisha ze-nZVI NPs; lokhu kwakheka kwe-lamellar nakho kuqinisekisa ukwenziwa ngempumelelo kwe-rGO. Ngaphezu kwalokho, ama-nZVI NPs anomumo oyindilinga onobukhulu bezinhlayiya kusukela ku-5.32 kuya ku-27 nm futhi afakwe kungqimba lwe-rGO ngokusabalala okucishe kufane. I-Eucalyptus leaf extract yasetshenziswa ukuhlanganisa i-Fe NPs/rGO; Imiphumela ye-TEM iphinde yaqinisekisa ukuthi imibimbi kungqimba lwe-rGO ithuthukise ukusabalala kwe-Fe NPs ngaphezu kwe-Fe NPs emsulwa futhi yandisa ukusabela kwezinhlanganisela. Imiphumela efanayo yatholakala nguBagheri et al. 28 lapho inhlanganisela yenziwa kusetshenziswa amasu e-ultrasonic anosayizi we-nanoparticle wensimbi ojwayelekile ongaba ngu-17.70 nm.
Ama-spectra e-FTIR e-A. halimus, nZVI, GO, rGO, kanye ne-rGO/nZVI aboniswe ku-Figs. 3A. Ukuba khona kwamaqembu asebenzayo ebusweni emaqabunga e-A. halimus kubonakala ku-3336 cm-1, okuhambisana nama-polyphenols, kanye no-1244 cm-1, okuhambisana namaqembu e-carbonyl akhiqizwa yiprotheni. Amanye amaqembu afana nama-alkanes ku-2918 cm-1, ama-alkenes ku-1647 cm-1 kanye ne-CO-O-CO extensions ku-1030 cm-1 nawo abonwe, okuphakamisa ukuba khona kwezingxenye zezitshalo ezisebenza njengezinto zokuvala futhi ezinesibopho sokululama kusuka ku-Fe2+ kuya ku-Fe0 kanye ne-GO kuya ku-rGO29. Ngokuvamile, ama-spectra e-nZVI abonisa iziqongo ezifanayo zokumuncwa njengoshukela obabayo, kodwa ngesimo esishintshile kancane. Ibhendi enamandla ivela ku-3244 cm-1 ehlotshaniswa nokudlidliza kwe-OH (ama-phenol), inani eliphakeme ku-1615 lihambisana ne-C=C, kanti amabhendi ku-1546 kanye no-1011 cm-1 avela ngenxa yokunwetshwa kwe-C=O (ama-polyphenol nama-flavonoid), amaqembu e-CN ama-aromatic amines nama-aliphatic amines nawo abonwe ku-1310 cm-1 kanye no-1190 cm-1, ngokulandelana. I-FTIR spectrum ye-GO ikhombisa ukuba khona kwamaqembu amaningi aqukethe i-oxygen enamandla aphezulu, kufaka phakathi ibhendi ye-alkoxy (CO) ku-1041 cm-1, ibhendi ye-epoxy (CO) ku-1291 cm-1, i-C=O. kwavela ibhendi lokudlidliza kokwelula kwe-C=C ku-1619 cm-1, ibhendi ku-1708 cm-1 kanye nebhendi ebanzi lokudlidliza kokwelula kweqembu le-OH ku-3384 cm-1, okuqinisekiswa yindlela ethuthukisiwe ye-Hummers, ephumelela ekuxiliseni inqubo ye-graphite. Uma kuqhathaniswa ama-composites e-rGO kanye ne-rGO/nZVI nama-spectra e-GO, amandla amanye amaqembu aqukethe umoya-mpilo, njenge-OH ku-3270 cm-1, ancishisiwe kakhulu, kanti amanye, njenge-C=O ku-1729 cm-1, ancishisiwe ngokuphelele., okubonisa ukususwa ngempumelelo kwamaqembu asebenzayo aqukethe umoya-mpilo ku-GO yi-A. halimus extract. Iziqongo ezintsha ezibukhali ze-rGO ekucindezelweni kwe-C=C zibonwa cishe ngo-1560 no-1405 cm-1, okuqinisekisa ukwehla kwe-GO ku-rGO. Ukwehluka kusuka ku-1043 kuya ku-1015 cm-1 kanye no-982 kuya ku-918 cm-1 kwabonwa, mhlawumbe ngenxa yokufakwa kwezinto zezitshalo31,32. UWeng et al., 2018 nabo babone ukuncishiswa okukhulu kwamaqembu asebenzayo ane-oxygen ku-GO, okuqinisekisa ukwakheka okuphumelelayo kwe-rGO ngokunciphisa i-bioreduction, njengoba iziqephu zamaqabunga e-eucalyptus, ezazisetshenziselwa ukuhlanganisa izinhlanganisela ze-iron graphene oxide ezincishisiwe, zibonise ama-spectra e-FTIR aseduze kwamaqembu asebenzayo ezingxenye zezitshalo.33.
A. I-FTIR spectrum ye-gallium, i-nZVI, i-rGO, i-GO, i-composite rGO/nZVI (A). Izinhlanganisela ze-Roentgenogrammy rGO, GO, nZVI kanye ne-rGO/nZVI (B).
Ukwakheka kwe-rGO/nZVI kanye ne-nZVI composites kuqinisekiswe kakhulu ngamaphethini e-X-ray diffraction (Isithombe 3B). I-peak ye-Fe0 enamandla aphezulu ibonwe ku-2Ɵ 44.5°, ehambisana ne-index (110) (JCPDS no. 06–0696)11. Enye i-peak ku-35.1° yendiza (311) ibangelwa yi-magnetite Fe3O4, i-63.2° ingahlotshaniswa ne-index ye-Miller yendiza (440) ngenxa yokuba khona kwe-ϒ-FeOOH (JCPDS no. 17-0536)34. Iphethini ye-X-ray ye-GO ikhombisa i-peak ebukhali ku-2Ɵ 10.3° kanye ne-peak enye ku-21.1°, okubonisa ukukhishwa okuphelele kwe-graphite futhi kugqamisa ukuba khona kwamaqembu aqukethe umoya-mpilo ebusweni be-GO35. Amaphethini ahlanganisiwe e-rGO kanye ne-rGO/nZVI aqophe ukunyamalala kweziqongo ze-GO eziphawulekayo kanye nokwakheka kweziqongo ezibanzi ze-rGO ku-2Ɵ 22.17 kanye no-24.7° kwezinhlanganisela ze-rGO kanye ne-rGO/nZVI, ngokulandelana, okuqinisekisile ukubuyiselwa ngempumelelo kwe-GO yizicucu zezitshalo. Kodwa-ke, kuphethini ye-rGO/nZVI ehlanganisiwe, iziqongo ezengeziwe ezihlotshaniswa nendiza ye-lattice ye-Fe0 (110) kanye ne-bcc Fe0 (200) zabonwa ku-44.9\(^\circ\) kanye no-65.22\(^\circ\), ngokulandelana.
I-zeta potential yi-potential ephakathi kwengqimba ye-ionic enamathiselwe ebusweni be-particle kanye nesisombululo samanzi esinquma izakhiwo ze-electrostatic zezinto futhi silinganise ukuqina kwayo. Ukuhlaziywa kwe-Zeta potential kwe-nZVI, GO, kanye ne-rGO/nZVI ezakhiwe ngezitshalo kubonise ukuqina kwazo ngenxa yokuba khona kwezindleko ezingezinhle ze--20.8, -22, kanye ne--27.4 mV, ngokulandelana, ebusweni bazo, njengoba kuboniswe ku-Figure S1A-C. . Imiphumela enjalo ihambisana nemibiko eminingana ekhuluma ngokuthi izixazululo eziqukethe izinhlayiya ezinamanani e-zeta potential angaphansi kwe--25 mV ngokuvamile zibonisa izinga eliphezulu lokuqina ngenxa yokucindezela kwe-electrostatic phakathi kwalezi zinhlayiya. Ukuhlanganiswa kwe-rGO kanye ne-nZVI kuvumela i-composite ukuthi ithole izindleko ezingezinhle kakhulu futhi ngaleyo ndlela inokuqina okuphezulu kune-GO noma i-nZVI yodwa. Ngakho-ke, isimo sokucindezela kwe-electrostatic sizoholela ekwakhekeni kwe-stable rGO/nZVI39 composites. Ubuso obungemuhle be-GO buvumela ukuthi ihlakazeke ngokulinganayo endaweni enamanzi ngaphandle kokuhlangana, okudala izimo ezinhle zokuxhumana ne-nZVI. Ishaja engemuhle ingahlotshaniswa nokuba khona kwamaqembu ahlukene asebenzayo ku-extract ebabayo ye-melon, okuqinisekisa nokusebenzisana phakathi kwe-GO kanye nezandulela zensimbi kanye ne-extract yesitshalo ukwakha i-rGO kanye ne-nZVI, ngokulandelana, kanye ne-complex ye-rGO/nZVI. Lezi zinhlanganisela zezitshalo zingasebenza njengezinto ezivala, njengoba zivimbela ukuhlanganiswa kwama-nanoparticles aphumayo futhi ngaleyo ndlela zandise ukuzinza kwazo40.
Ukwakheka kwezinto eziyisisekelo kanye nezimo ze-valence ze-nZVI kanye ne-rGO/nZVI composites kunqunywe yi-XPS (Umfanekiso 4). Ucwaningo lwe-XPS lukhombisile ukuthi i-composite ye-rGO/nZVI yakhiwe kakhulu yizakhi C, O, kanye ne-Fe, ezihambisana nokumapha kwe-EDS (Umfanekiso 4F–H). I-spectrum ye-C1s inama-peak amathathu ku-284.59 eV, 286.21 eV kanye ne-288.21 eV emele i-CC, i-CO kanye ne-C=O, ngokulandelana. I-spectrum ye-O1s yahlukaniswa ngama-peak amathathu, kufaka phakathi i-531.17 eV, i-532.97 eV, kanye ne-535.45 eV, ezabelwe amaqembu e-O=CO, i-CO, kanye ne-NO, ngokulandelana. Kodwa-ke, ama-peak angu-710.43, 714.57 kanye ne-724.79 eV abhekisela ku-Fe 2p3/2, Fe+3 kanye ne-Fe p1/2, ngokulandelana. Ama-spectra e-XPS e-nZVI (Umfanekiso 4C-E) abonise iziqongo zezinto C, O, kanye ne-Fe. Iziqongo ku-284.77, 286.25, kanye ne-287.62 eV ziqinisekisa ukuba khona kwama-alloy e-iron-carbon, njengoba ebhekisela ku-CC, C-OH, kanye ne-CO, ngokulandelana. I-spectrum ye-O1s ihambelana neziqongo ezintathu ze-C–O/iron carbonate (531.19 eV), i-hydroxyl radical (532.4 eV) kanye ne-O–C=O (533.47 eV). Iziqongo ku-719.6 zibangelwa yi-Fe0, kuyilapho i-FeOOH ikhombisa iziqongo ku-717.3 kanye ne-723.7 eV, ngaphezu kwalokho, iziqongo ku-725.8 eV zibonisa ukuba khona kwe-Fe2O342.43.
Izifundo ze-XPS ze-nZVI kanye ne-rGO/nZVI composites, ngokulandelana (A, B). Ama-spectra aphelele e-nZVI C1s (C), Fe2p (D), kanye ne-O1s (E) kanye ne-rGO/nZVI C1s (F), Fe2p (G), O1s (H) composite.
I-isotherm ye-N2 adsorption/desorption (Isithombe 5A, B) ikhombisa ukuthi i-nZVI kanye ne-rGO/nZVI composites zingezohlobo II. Ngaphezu kwalokho, indawo ethile yobuso (i-SBET) ye-nZVI ikhuphuke isuka ku-47.4549 yaya ku-152.52 m2/g ngemva kokufiphaza nge-rGO. Lo mphumela ungachazwa ngokuncipha kwezakhiwo zikagesi ze-nZVI ngemva kokufiphaza nge-rGO, ngaleyo ndlela kunciphisa ukuhlanganiswa kwezinhlayiya futhi kwandise indawo yobuso be-composites. Ngaphezu kwalokho, njengoba kuboniswe ku-Fig. 5C, ivolumu ye-pore (8.94 nm) ye-rGO/nZVI composite iphakeme kuneye-nZVI yokuqala (2.873 nm). Lo mphumela uvumelana no-El-Monaem et al. 45.
Ukuze kuhlolwe amandla okufaka i-DC phakathi kwe-rGO/nZVI composites kanye ne-nZVI yokuqala kuye ngokwanda kokuhlushwa kokuqala, kwenziwa ukuqhathanisa ngokungeza umthamo oqhubekayo we-adsorbent ngayinye (0.05 g) ku-DC ekuhlushweni kokuqala okuhlukahlukene. Isixazululo esihloliwe [25]. –100 mg l–1] ku-25°C. Imiphumela ibonise ukuthi ukusebenza kahle kokususa (94.6%) kwe-rGO/nZVI composite kwakuphakeme kunokwe-nZVI yokuqala (90%) ekuhlushweni okuphansi (25 mg L-1). Kodwa-ke, lapho ukuhlushwa kokuqala kukhushulwa ku-100 mg L-1, ukusebenza kahle kokususa kwe-rGO/nZVI kanye ne-nZVI yabazali kwehle kwaya ku-70% kanye no-65%, ngokulandelana (Isithombe 6A), okungaba ngenxa yezindawo ezimbalwa ezisebenzayo kanye nokuwohloka kwezinhlayiya ze-nZVI. Ngokuphambene nalokho, i-rGO/nZVI ikhombise ukusebenza kahle okuphezulu kokususwa kwe-DC, okungase kube ngenxa yomphumela wokubambisana phakathi kwe-rGO ne-nZVI, lapho izindawo ezisebenzayo ezizinzile ezitholakalayo zokufakwa kwe-adsorption ziphakeme kakhulu, futhi esimweni se-rGO/nZVI, i-DC eningi ingafakwa i-adsorption kune-nZVI engashintshi. Ngaphezu kwalokho, ku-fig. 6B ikhombisa ukuthi amandla okufakwa kwe-adsorption we-rGO/nZVI kanye ne-nZVI composites akhuphuke kusuka ku-9.4 mg/g kuya ku-30 mg/g kanye no-9 mg/g, ngokulandelana, ngokwanda kokuhlushwa kokuqala kusuka ku-25–100 mg/L. -1.1 kuya ku-28.73 mg g-1. Ngakho-ke, izinga lokususwa kwe-DC lalihlobene kabi nokuhlushwa kokuqala kwe-DC, okwakubangelwa inani elilinganiselwe lezikhungo zokusabela ezisekelwa yi-adsorbent ngayinye yokufakwa kwe-adsorption kanye nokususwa kwe-DC esixazululweni. Ngakho-ke, kungaphethwa ngale miphumela ukuthi izinhlanganisela ze-rGO/nZVI zisebenza kahle kakhulu ekumuncweni nasekuncishisweni, futhi i-rGO ekwakhiweni kwe-rGO/nZVI ingasetshenziswa kokubili njenge-adsorbent kanye nempahla yokuthwala.
Ukusebenza kahle kokususa kanye nomthamo wokungenisa we-DC we-rGO/nZVI kanye ne-nZVI composite kwakuyi-(A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, umthamo = 0.05 g], i-pH. kumthamo wokungenisa kanye nokusebenza kahle kokususa we-DC ku-rGO/nZVI composites (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, umthamo = 0.05 g].
I-pH yesixazululo iyisici esibalulekile ekufundweni kwezinqubo zokumunca, njengoba ithinta izinga le-ionization, i-speciation, kanye ne-ionization ye-adsorbent. Ukuhlolwa kwenziwe ku-25°C ngomthamo we-adsorbent oqhubekayo (0.05 g) kanye nokuhlushwa kokuqala okungu-50 mg L-1 ebangeni le-pH (3–11). Ngokusho kokubuyekezwa kwezincwadi46, i-DC iyi-molecule ye-amphiphilic enamaqembu amaningana asebenzayo a-ionizable (ama-phenols, amaqembu ama-amino, ama-alcohols) emazingeni ahlukahlukene e-pH. Ngenxa yalokho, imisebenzi ehlukahlukene ye-DC kanye nezakhiwo ezihlobene ebusweni be-rGO/nZVI composite ingase isebenzisane ngogesi futhi ingaba khona njenge-cations, zwitterions, kanye nama-anion, i-molecule ye-DC ikhona njenge-cationic (DCH3+) ku-pH < 3.3, zwitterionic (DCH20) 3.3 < pH < 7.7 kanye ne-anionic (DCH− noma i-DC2−) ku-PH 7.7. Ngenxa yalokho, imisebenzi ehlukahlukene ye-DC kanye nezakhiwo ezihlobene ebusweni be-rGO/nZVI composite ingase isebenzisane ngogesi futhi ingaba khona njenge-cations, zwitterions, kanye nama-anion, i-molecule ye-DC ikhona njenge-cationic (DCH3+) ku-pH < 3.3, zwitterionic (DCH20) 3.3 < pH < 7.7 kanye ne-anionic (DCH- noma i-DC2-) ku-PH 7.7. В результате различные функции ДК и связанных с ними структур на поверхности композита rGO/nZVI могут взаимодействовать электровать электровать виде катионов, цвиттер-ионов and анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер-ионный (DCH20)
Umphumela wokushisa ekumuncweni kwesisombululo samanzi se-DC wenziwa ku-(25–55°C). Isibalo 7A sibonisa umphumela wokwanda kokushisa ekusebenzeni kahle kokususwa kwama-antibiotic e-DC ku-rGO/nZVI, kusobala ukuthi umthamo wokususa kanye nekhono lokumuncwa kukhuphuke kusuka ku-83.44% kanye no-13.9 mg/g kuya ku-47% kanye no-7.83 mg/g. ngokulandelana. Lokhu kwehla okukhulu kungase kube ngenxa yokwanda kwamandla okushisa kwama-ion e-DC, okuholela ekumuncweni47.
Umphumela Wokushisa Ekusebenzeni Kahle Kokususa kanye Nomthamo Wokumunca we-CD kuma-Composites e-rGO/nZVI (A) [Co = 50 mg L–1, pH = 7, Umthamo = 0.05 g], Umthamo Wokumunca Ekusebenzeni Kahle Kokususa kanye Nokususa Ukusebenza Kahle kwe-CD Umphumela Wokugxila Kokuqala Emandleni Okumunca kanye nokusebenza kahle kokususwa kwe-DC ku-composite ye-rGO/nSVI (B) [Co = 50 mg L–1, pH = 7, T = 25°C] (C, D) [Co = 25–100 mg L–1, pH = 7, T = 25 °C, umthamo = 0.05 g].
Umphumela wokwandisa umthamo we-composite adsorbent rGO/nZVI kusuka ku-0.01 g kuya ku-0.07 g ekusebenzeni kahle kokususa kanye namandla okumunca uboniswa ku-Fig. 7B. Ukwanda komthamo we-adsorbent kuholele ekwehleni komthamo wokumunca kusuka ku-33.43 mg/g kuya ku-6.74 mg/g. Kodwa-ke, ngokwanda komthamo we-adsorbent kusuka ku-0.01 g kuya ku-0.07 g, ukusebenza kahle kokususa kuyanda kusuka ku-66.8% kuya ku-96%, okungahle kuhlotshaniswe nokwanda kwenani lezikhungo ezisebenzayo ebusweni be-nanocomposite.
Umphumela wokuhlushwa kokuqala kumthamo wokumunca kanye nokusebenza kahle kokususa [25–100 mg L-1, 25°C, pH 7, umthamo ongu-0.05 g] wafundwa. Lapho ukuhlushwa kokuqala kukhushulwa kusuka ku-25 mg L-1 kuya ku-100 mg L-1, iphesenti lokususa le-composite ye-rGO/nZVI lehla kusuka ku-94.6% kuya ku-65% (Isithombe 7C), mhlawumbe ngenxa yokungabikho kwezindawo ezisebenzayo ezifiselekayo. . Imunca ukuhlushwa okukhulu kwe-DC49. Ngakolunye uhlangothi, njengoba ukuhlushwa kokuqala kwanda, umthamo wokumunca nawo wanda kusuka ku-9.4 mg/g kuya ku-30 mg/g kuze kube yilapho kufinyelelwa ukulingana (Isithombe 7D). Lokhu kusabela okungenakugwenywa kungenxa yokwanda kwamandla okushayela okuhlushwa kokuqala kwe-DC okukhulu kunokumelana kokudluliselwa kwesisindo se-DC ion ukuze kufinyelelwe ebusweni 50 be-composite ye-rGO/nZVI.
Isikhathi sokuxhumana kanye nezifundo ze-kinetic zihlose ukuqonda isikhathi sokulingana sokumuncwa. Okokuqala, inani le-DC elimuncwayo phakathi nemizuzu yokuqala engama-40 yesikhathi sokuxhumana lalicishe libe yingxenye yenani eliphelele elimuncwayo phakathi nesikhathi sonke (imizuzu eyi-100). Ngenkathi ama-molecule e-DC esixazululweni eshayisana okwenza ukuthi athuthele ngokushesha ebusweni be-rGO/nZVI composite okuholela ekumuncweni okukhulu. Ngemva kwemizuzu engama-40, ukumuncwa kwe-DC kwanda kancane kancane kwaze kwaba yilapho kufinyelelwa ekulinganeni ngemva kwemizuzu engama-60 (Isithombe 7D). Njengoba inani elifanele limuncwayo phakathi nemizuzu yokuqala engama-40, kuzoba nokushayisana okumbalwa nama-molecule e-DC futhi kuzoba nezindawo ezimbalwa ezisebenzayo zama-molecule angamuncwayo. Ngakho-ke, izinga lokumuncwa lingancishiswa51.
Ukuze kuqondwe kangcono i-adsorption kinetics, kusetshenziswe ama-line plots e-pseudo first order (Isithombe 8A), i-pseudo second order (Isithombe 8B), kanye namamodeli e-Elovich (Isithombe 8C). Kusukela kumapharamitha atholwe ezifundweni ze-kinetic (Ithebula S1), kuba sobala ukuthi imodeli ye-pseudosecond iyimodeli engcono kakhulu yokuchaza i-adsorption kinetics, lapho inani le-R2 libekwe phezulu kunakwamanye amamodeli amabili. Kukhona futhi ukufana phakathi kwamandla e-adsorption abaliwe (qe, cal). I-pseudo-second order kanye namanani okuhlola (qe, exp.) kuwubufakazi obengeziwe bokuthi i-pseudo-second order iyimodeli engcono kunamanye amamodeli. Njengoba kuboniswe kuThebula 1, amanani e-α (isilinganiso sokuqala se-adsorption) kanye ne-β (i-desorption constant) aqinisekisa ukuthi izinga le-adsorption liphakeme kunesilinganiso se-desorption, okubonisa ukuthi i-DC ivame ukumunca kahle ku-rGO/nZVI52 composite. .
Ama-kinetic plots e-adsorption aqondile e-oda le-pseudo-second (A), i-pseudo-first order (B) kanye ne-Elovich (C) [Co = 25–100 mg l–1, pH = 7, T = 25 °C, umthamo = 0.05 g].
Izifundo ze-adsorption isotherms zisiza ekunqumeni umthamo wokungenisa we-adsorbent (i-RGO/nRVI composite) kumazinga ahlukahlukene we-adsorbate (DC) kanye namazinga okushisa esistimu. Umthamo omkhulu wokungenisa ubalwe kusetshenziswa i-Langmuir isotherm, okubonisa ukuthi i-adsorption yayifana futhi ifaka ukwakheka kwe-monolayer ye-adsorbate ebusweni be-adsorbent ngaphandle kokuxhumana phakathi kwabo53. Amanye amamodeli amabili e-isotherm asetshenziswa kabanzi amamodeli e-Freundlich kanye ne-Temkin. Nakuba imodeli ye-Freundlich ingasetshenziswa ukubala umthamo wokungenisa, iyasiza ukuqonda inqubo yokungenisa engafani nokuthi izikhala ku-adsorbent zinamandla ahlukene, kuyilapho imodeli ye-Temkin isiza ukuqonda izakhiwo zomzimba nezamakhemikhali ze-adsorption54.
Izibalo 9A-C zibonisa ama-line plots amamodeli e-Langmuir, Freindlich, kanye ne-Temkin, ngokulandelana. Amanani e-R2 abalwe kusukela kuma-line plots e-Freundlich (Isithombe 9A) kanye ne-Langmuir (Isithombe 9B) futhi aboniswe kuThebula 2 abonisa ukuthi i-DC adsorption ku-rGO/nZVI composite ilandela amamodeli e-isotherm e-Freundlich (0.996) kanye ne-Langmuir (0.988) kanye ne-Temkin (0.985). Umthamo omkhulu we-adsorption (qmax), obalwe kusetshenziswa imodeli ye-isotherm ye-Langmuir, wawungu-31.61 mg g-1. Ngaphezu kwalokho, inani elibalwe le-dimensionless separation factor (RL) liphakathi kuka-0 no-1 (0.097), okubonisa inqubo ye-adsorption evumayo. Ngaphandle kwalokho, i-Freundlich constant ebalwe (n = 2.756) ikhombisa ukukhetha kwale nqubo yokumunca. Ngokusho kwemodeli eqondile ye-Temkin isotherm (Isithombe 9C), ukumuncwa kwe-DC ku-composite ye-rGO/nZVI kuyinqubo yokumuncwa ngokomzimba, njengoba i-b ingu-˂ 82 kJ mol-1 (0.408)55. Nakuba ukumuncwa ngokomzimba kuvame ukuqondiswa amandla abuthakathaka e-van der Waals, ukumuncwa kwamandla aqondile ku-composite ye-rGO/nZVI kudinga amandla aphansi okumuncwa [56, 57].
Ama-isotherms e-Freundlich (A), Langmuir (B), kanye ne-Temkin (C) aqondile okumunca [Co = 25–100 mg L–1, pH = 7, T = 25 °C, umthamo = 0.05 g]. Isakhiwo se-van't Hoff equation sokumunca kwe-DC yi-rGO/nZVI composites (D) [Co = 25–100 mg l-1, pH = 7, T = 25–55 °C kanye nomthamo = 0.05 g].
Ukuze kuhlolwe umphumela wokushintsha kwezinga lokushisa lokusabela ekususweni kwe-DC kusuka kuma-composites e-rGO/nZVI, amapharamitha e-thermodynamic afana noshintsho lwe-entropy (ΔS), ushintsho lwe-enthalpy (ΔH), kanye noshintsho lwamandla amahhala (ΔG) abalwe kusukela kuzibalo. 3 kanye no-458.
lapho \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) – i-thermodynamic equilibrium constant, i-Ce ne-CAe – i-rGO esixazululweni, ngokulandelana /nZVI DC concentrations at surface equilibrium. I-R ne-RT yi-gas constant kanye ne-adsorption temperature, ngokulandelana. Ukudweba i-ln Ke ngokumelene ne-1/T kunikeza umugqa oqondile (Isithombe 9D) lapho i-∆S kanye ne-∆H kungatholakala khona.
Inani elibi le-ΔH libonisa ukuthi inqubo i-exothermic. Ngakolunye uhlangothi, inani le-ΔH lingaphakathi kwenqubo yokumunca ngokomzimba. Amanani abi e-ΔG kuThebula 3 abonisa ukuthi ukumunca kungenzeka futhi kuyazenzekela. Amanani abi e-ΔS abonisa ukuhleleka okuphezulu kwama-molecule amuncayo endaweni yokuxhumana yoketshezi (Ithebula 3).
Ithebula 4 liqhathanisa inhlanganisela ye-rGO/nZVI nezinye izinto ezifakwayo ezibikwe ezifundweni zangaphambilini. Kusobala ukuthi inhlanganisela ye-VGO/nCVI inamandla aphezulu okufinyeza futhi ingaba yinto ethembisayo yokususa ama-antibiotic e-DC emanzini. Ngaphezu kwalokho, ukufinyeza kwezingxenye ze-rGO/nZVI kuyinqubo esheshayo enesikhathi sokulinganisa semizuzu engama-60. Izakhiwo ezinhle kakhulu zokufinyeza kwezingxenye ze-rGO/nZVI zingachazwa ngomphumela wokubambisana kwe-rGO kanye ne-nZVI.
Izibalo 10A, B zibonisa indlela enengqondo yokususa ama-antibiotic e-DC yi-rGO/nZVI kanye ne-nZVI complexes. Ngokusho kwemiphumela yokuhlolwa komphumela we-pH ekusebenzeni kahle kwe-DC adsorption, ngokwanda kwe-pH kusuka ku-3 kuya ku-7, i-DC adsorption ku-rGO/nZVI composite ayizange ilawulwe ukusebenzisana kwe-electrostatic, ngoba yasebenza njenge-zwitterion; ngakho-ke, ushintsho enanini le-pH aluzange luthinte inqubo ye-adsorption. Ngemva kwalokho, indlela ye-adsorption ingalawulwa ukusebenzisana okungewona ama-electrostatic njengokubopha kwe-hydrogen, imiphumela ye-hydrophobic, kanye nokusebenzisana kwe-π-π stacking phakathi kwe-rGO/nZVI composite kanye ne-DC66. Kwaziwa kahle ukuthi indlela ye-aromatic adsorbates ezindaweni ze-graphene enezingqimba ichazwe ngokusebenzisana kwe-π-π stacking njengamandla amakhulu okushayela. I-composite iyinto enezingqimba efana ne-graphene enomkhawulo wokumuncwa ongama-233 nm ngenxa yokuguquka kwe-π-π*. Ngokusekelwe ekubeni khona kwezindandatho ezine ze-aromatic esakhiweni sama-molecule se-DC adsorbate, sicabange ukuthi kukhona indlela yokusebenzisana kwe-π-π-stacking phakathi kwe-aromatic DC (i-π-electron acceptor) kanye nesifunda esicebile ngama-π-electron ebusweni be-RGO. /nZVI composites. Ngaphezu kwalokho, njengoba kuboniswe ku-Fig. 10B, kwenziwa izifundo ze-FTIR ukuze kufundwe ukusebenzisana kwama-molecule kwama-composites e-rGO/nZVI ne-DC, kanye nama-spectra e-FTIR wama-composites e-rGO/nZVI ngemva kokumuncwa kwe-DC aboniswe ku-Figure 10B. 10b. I-peak entsha ibonwa ku-2111 cm-1, okuhambisana nokudlidliza kohlaka lwe-C=C bond, okubonisa ukuba khona kwamaqembu asebenzayo e-organic ahambisanayo ebusweni be-67 rGO/nZVI. Ezinye iziqongo ziyashintsha kusuka ku-1561 kuya ku-1548 cm-1 kanye nokusuka ku-1399 kuya ku-1360 cm-1, okuqinisekisa nokuthi ukusebenzisana kwe-π-π kudlala indima ebalulekile ekumuncweni kwe-graphene kanye nokungcola okuphilayo68,69. Ngemva kokumuncwa kwe-DC, amandla amanye amaqembu aqukethe umoya-mpilo, njenge-OH, ehle afinyelela ku-3270 cm-1, okuphakamisa ukuthi ukubopha kwe-hydrogen kungenye yezindlela zokumuncwa. Ngakho-ke, ngokusekelwe emiphumeleni, ukumuncwa kwe-DC ku-composite ye-rGO/nZVI kwenzeka ikakhulukazi ngenxa yokusebenzisana kwe-π-π stacking kanye nama-H-bond.
Indlela enengqondo yokumuncwa kwama-antibiotic e-DC yi-rGO/nZVI kanye ne-nZVI complexes (A). Ama-spectra okumuncwa kwe-FTIR e-DC ku-rGO/nZVI kanye ne-nZVI (B).
Ukuqina kwamabhande okumunca e-nZVI ku-3244, 1615, 1546, kanye no-1011 cm–1 kwanda ngemva kokumunca kwe-DC ku-nZVI (Isithombe 10B) uma kuqhathaniswa ne-nZVI, okufanele kuhlotshaniswe nokusebenzisana namaqembu asebenzayo angaba khona amaqembu e-carboxylic acid O ku-DC. Kodwa-ke, leli phesenti eliphansi lokudluliselwa kuwo wonke amabhande abonwe alibonisi ushintsho olubalulekile ekusebenzeni kahle kokumunca kwe-phytosynthetic adsorbent (nZVI) uma kuqhathaniswa ne-nZVI ngaphambi kwenqubo yokumunca. Ngokusho kocwaningo oluthile lokususwa kwe-DC nge-nZVI71, lapho i-nZVI isabela ne-H2O, ama-electron ayakhishwa bese i-H+ isetshenziswa ukukhiqiza i-hydrogen esebenzayo encishiswa kakhulu. Okokugcina, amanye ama-cationic compounds amukela ama-electron avela ku-hydrogen esebenzayo, okuholela ku--C=N kanye no--C=C-, okubangelwa ukuhlukana kwendandatho ye-benzene.
Isikhathi sokuthunyelwe: Novemba-14-2022