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Kulo msebenzi, izinhlanganisela ze-rGO/nZVI zenziwe okokuqala ngqa kusetshenziswa inqubo elula nevumelana nemvelo kusetshenziswa ukukhishwa kweqabunga eliphuzi le-Sophora njenge-ejenti yokunciphisa nesiqinisi ukuze kuhambisane nezimiso zamakhemikhali “aluhlaza”, njengokuhlanganisa amakhemikhali angalimazi kangako. Amathuluzi amaningana asetshenziselwe ukuqinisekisa ukuhlanganiswa okuphumelelayo kwezinhlanganisela, njenge-SEM, i-EDX, i-XPS, i-XRD, i-FTIR, namandla e-zeta, abonisa ukwakhiwa okuphumelelayo kwenhlanganisela. Umthamo wokususwa wezinhlanganisela zenoveli kanye ne-nZVI emsulwa ekugxiliseni okuhlukahlukene kokuqala kwe-antibiotic doxycycline yaqhathaniswa ukuze kuphenywe umthelela we-synergistic phakathi kwe-rGO ne-NZVI. Ngaphansi kwemibandela yokususa engu-25mg L-1, 25°C kanye no-0.05g, izinga lokukhishwa kwesikhangiso se-nZVI elihlanzekile lalingu-90%, kuyilapho izinga lokukhishwa kwe-adsorptive le-doxycycline ngenhlanganisela ye-rGO/nZVI lifinyelele ku-94.6%, okuqinisekisa ukuthi i-NZVI ne-rGO . Inqubo ye-adsorption ihambisana ne-oda lesibili-mbumbulu futhi ivumelana kahle nemodeli ye-Freundlich enomthamo omkhulu we-adsorption ongu-31.61 mg g-1 ku-25 °C kanye ne-pH 7. Indlela ephusile yokususwa kwe-DC ihlongoziwe. Ngaphezu kwalokho, ukusebenziseka kabusha kwenhlanganisela ye-rGO/nZVI kwaba ngu-60% ngemva kwemijikelezo eyisithupha elandelanayo yokuvuselela.
Ukuntuleka kwamanzi nokungcola manje kuwusongo olukhulu kuwo wonke amazwe. Eminyakeni yamuva nje, ukungcoliswa kwamanzi, ikakhulukazi ukungcoliswa kwamagciwane, kunyukile ngenxa yokwanda kokukhiqizwa nokusetshenziswa ngesikhathi sobhadane lwe-COVID-1,2,3. Ngakho-ke, ukuthuthukiswa kobuchwepheshe obusebenzayo bokuqeda ama-antibiotic emanzini angcolile kuwumsebenzi ophuthumayo.
Enye yemithi elwa namagciwane eyi-semi-synthetic evela eqenjini le-tetracycline i-doxycycline (DC)4,5. Kuye kwabikwa ukuthi izinsalela ze-DC emanzini angaphansi komhlaba namanzi angaphezulu azikwazi ukuguqulwa kwe-metabolized, kuphela i-20-50% ye-metabolized bese enye ikhishwa endaweni ezungezile, okubangela izinkinga ezinkulu zemvelo nempilo6.
Ukuchayeka ku-DC emazingeni aphansi kungabulala ama-microorganisms e-photosynthetic asemanzini, kusongela ukusabalala kwamagciwane e-antimicrobial, futhi kwandise ukumelana ne-antimicrobial, ngakho-ke lokhu kungcola kufanele kukhishwe emanzini angcolile. Ukuwohloka kwemvelo kwe-DC emanzini kuyinqubo ehamba kancane kakhulu. Izinqubo ze-Physico-chemical ezifana ne-photolysis, biodegradation kanye ne-adsorption zingehlisa kuphela ekugxilweni okuphansi futhi ngamanani aphansi kakhulu7,8. Nokho, indlela eyonga kakhulu, elula, evumelana nemvelo, elula ukuyiphatha futhi ephumelelayo i-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, ne-tetracycline. Leli khono lingenxa yezakhiwo ezimangalisayo i-NZVI enazo, njengokusebenza kabusha okuphezulu, indawo enkulu engaphezulu, nezingosi eziningi ezibophezela ngaphandle11. Kodwa-ke, i-NZVI ijwayele ukuhlanganisa emithonjeni ye-aqueous ngenxa yamandla e-van der Wells kanye nezakhiwo eziphakeme kazibuthe, okunciphisa ukusebenza kwayo ekususeni ukungcola ngenxa yokwakheka kwezingqimba ze-oxide ezivimbela ukusebenza kabusha kwe-nZVI10,12. Ukuhlanganiswa kwezinhlayiya ze-nZVI kungancishiswa ngokushintsha indawo yazo ngama-surfactants nama-polymers noma ngokuzihlanganisa namanye ama-nanomaterials ngendlela yezinhlanganisela, okubonakale kuyindlela esebenzayo yokuthuthukisa ukuzinza kwazo endaweni13,14.
I-Graphene iyi-carbon-dimensional carbon nanomaterial ehlanganisa ama-athomu ekhabhoni e-sp2-hybridized ahlelwe ku-lattice yekhekheba lezinyosi. Inendawo enkulu engaphezulu, amandla abalulekile emishini, umsebenzi omuhle kakhulu we-electrocatalytic, izinga eliphezulu le-thermal conductivity, ukuhamba kwe-electron esheshayo, kanye nezinto ezifanele zokuthwala ukusekela ama-nanoparticles angaphili endaweni yawo. Inhlanganisela ye-nanoparticles yensimbi kanye ne-graphene ingadlula kakhulu izinzuzo zomuntu ngamunye wento ngayinye futhi, ngenxa yezakhiwo zayo eziphakeme zomzimba namakhemikhali, inikeza ukusabalalisa okuphelele kwama-nanoparticles ukuze kusetshenziswe ukwelashwa kwamanzi okuphumelelayo15.
Ukukhishwa kwezitshalo kuyindlela engcono kakhulu yama-ejenti anciphisa amakhemikhali ayingozi avame ukusetshenziswa ekuhlanganiseni kwe-graphene oxide (rGO) encishisiwe ne-nZVI ngoba ayatholakala, angabizi, anesinyathelo esisodwa, aphephile endaweni, futhi angasetshenziswa njengama-ejenti anciphisayo. njengama-flavonoids nama-phenolic compounds nawo asebenza njenge-stabilizer. Ngakho-ke, i-Atriplex halimus L. i-leaf extract isetshenziswe njenge-ejenti yokulungisa nokuvala ukuhlanganiswa kwezinhlanganisela ze-rGO/nZVI kulolu cwaningo. I-Atriplex halimus yomndeni wakwa-Amaranthaceae iyisihlahla esihlala isikhathi eside esithanda initrogen enobubanzi bendawo16.
Ngokuya ngezincwadi ezitholakalayo, i-Atriplex halimus (A. halimus) yaqale yasetshenziswa ukwenza izinhlanganisela ze-rGO/nZVI njengendlela yokuhlanganisa eyongayo nevumelana nemvelo. Ngakho, inhloso yalo msebenzi inezingxenye ezine: (1) i-phytosynthesis ye-rGO/nZVI kanye nezinhlanganisela ze-nZVI zabazali zisebenzisa i-A. halimus aquatic leaf extract, (2) ukuhlukaniswa kwezinhlamvu ze-phytosynthesized composite kusetshenziswa izindlela eziningi zokuqinisekisa ukwakhiwa kwazo okuphumelelayo, (3) ) funda umthelela we-synergistic we-rGO ne-nZVI ekukhangisweni nasekususweni kokungcola okuphilayo kwama-antibiotic e-doxycycline ngaphansi kwemingcele ehlukene yokusabela, nokwandisa izimo zenqubo ye-adsorption, (3) phenya izinto eziyinhlanganisela ekwelapheni 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 e-Sigma-Aldrich, e-USA. I-sodium hydroxide (NaOH, 97%), i-ethanol (C2H5OH, 99.9%) ne-hydrochloric acid (HCl, 37%) ithengwe kwa-Merck, e-USA. I-NaCl, i-KCl, i-CaCl2, i-MnCl2 ne-MgCl2 ithengwe kwa-Tianjin Comio Chemical Reagent Co., Ltd. Wonke ama-reagents anokuhlaziya okuphezulu kokuhlaziya. Amanzi acwecwe kabili asetshenziselwa ukulungisa zonke izixazululo ezinamanzi.
Izibonelo ezimele ze-A. halimus ziqoqwe endaweni yazo yemvelo e-Nayile Delta nasezindaweni ezigudle ugu lweMedithera e-Egypt. Izinto zezitshalo zaqoqwa ngokuhambisana neziqondiso ezisebenzayo zikazwelonke nezamazwe ngamazwe17. UProf. Manal Fawzi uhlonze izibonelo zezitshalo ngokusho kwe-Boulos18, futhi uMnyango wezeSayensi yezeMvelo wase-Alexandria University ugunyaza ukuqoqwa kwezinhlobo zezitshalo ezihlolisisiwe ngezinjongo zesayensi. Amasampula amavawusha abanjwe e-Tanta University Herbarium (TANE), izinombolo zamavawusha. 14 122–14 127, indawo yomphakathi ehlinzeka ngokufinyelela ezintweni ezidiphozithiwe. Ngaphezu kwalokho, ukususa uthuli noma ukungcola, usike amaqabunga esitshalo abe yizicucu ezincane, hlambulula izikhathi ezi-3 ngompompi namanzi acwecwe, bese womisa ku-50 ° C. Isitshalo sichotshoziwe, i-5 g ye-powder ecolekile yacwiliswa ku-100 ml wamanzi acwengekile futhi inyakaziswa ku-70 ° C imizuzu engu-20 ukuze kutholakale ukukhishwa. Ukukhishwa okutholiwe kwe-Bacillus nicotianae kwahlungwa ngephepha lesihlungi se-Whatman futhi kwagcinwa kumashubhu ahlanzekile futhi abulala inzalo ku-4°C ukuze asetshenziswe futhi.
Njengoba kuboniswe kuMfanekiso 1, i-GO yenziwe nge-graphite powder ngendlela ye-Hummers eguquliwe. I-10 mg ye-GO powder yahlakazwa ku-50 ml wamanzi e-deionized imizuzu engu-30 ngaphansi kwe-sonication, bese kuthi i-0.9 g ye-FeCl3 ne-2.9 g ye-NaAc ixutshwe imizuzu engu-60. I-20 ml ye-atriplex leaf extract yengezwe kwisisombululo esinyakazayo ngokugqugquzela futhi ishiywe ku-80 ° C amahora angu-8. Ukumiswa okumnyama okumphumela kwahlungwa. Ama-nanocomposites alungisiwe ahlanzwa nge-ethanol namanzi ane-bidistilled bese omiswa kuhhavini we-vacuum engu-50 ° C amahora angu-12.
Izithombe ezihleliwe nezedijithali zokuhlanganiswa okuluhlaza kwe-rGO/nZVI kanye ne-nZVI izakhiwo kanye nokususwa kwemithi elwa namagciwane e-DC emanzini angcolile kusetshenziswa i-Atriplex halimus extract.
Kafushane, njengoba kukhonjisiwe kumfanekiso 1, u-10 ml wesisombululo se-iron chloride equkethe 0.05 M Fe3+ ions wengezwa ngokudonsela phansi ku-20 ml wesisombululo esikhipha amaqabunga ababayo imizuzu engama-60 ngokushisisa nokunyakazisa okusesilinganisweni, bese isixazululo sabe sesifakwa phakathi I-14,000 rpm (Hermle , 15,000 rpm) imizuzu engu-15 ukunikeza izinhlayiya ezimnyama, ezabe zigezwa izikhathi ezingu-3 nge-ethanol namanzi a-distilled bese zomiswa kuhhavini we-vacuum ku-60 ° C. ubusuku bonke.
Inhlanganisela ye-rGO/nZVI ne-nZVI ehlanganiswe nezitshalo iphawulwe nge-UV-visible spectroscopy (T70/T80 uchungechunge lwe-UV/Vis spectrophotometers, i-PG Instruments Ltd, UK) ebangeni lokuskena elingu-200-800 nm. Ukuze kuhlaziywe isimo sendawo kanye nokusabalalisa usayizi wezinhlanganisela ze-rGO/nZVI kanye ne-NZVI, kusetshenziswe i-TEM spectroscopy (JOEL, JEM-2100F, Japan, voltage esheshayo engu-200 kV) yasetshenziswa. Ukuhlola amaqembu asebenzayo angabandakanyeka ekukhishweni kwezitshalo okubophezelekile ekubuyiseleni nasekuqiniseni inqubo, i-spectroscopy ye-FT-IR yenziwa (i-spectrometer ye-JASCO ebangeni lika-4000-600 cm-1). Ngaphezu kwalokho, i-zeta potential analyzer (Zetasizer Nano ZS Malvern) yasetshenziswa ukutadisha ukushaja okungaphezulu kwama-nanomaterials ahlanganisiwe. Ezilinganisweni ze-X-ray diffraction ye-nanomaterials eyimpuphu, i-X-ray diffractometer (X'PERT PRO, e-Netherlands) yasetshenziswa, esebenza ngamandla amanje (40 mA), voltage (45 kV) ku-2θ ukusuka ku-20° ukuya ku-80 ° kanye nemisebe ye-CuKa1 (\(\lambda =\ ) 1.54056 Ao). I-spectrometer ye-X-ray ehlukanisa amandla (EDX) (imodeli JEOL JSM-IT100) yayinomthwalo wemfanelo wokutadisha ukwakheka okuyisisekelo lapho iqoqa i-Al K-α monochromatic X-rays ukusuka ku- -10 ukuya ku-1350 eV ku-XPS, usayizi wendawo 400 μm K-ALPHA (I-Thermo Fisher Scientific, USA) amandla okudlulisa e-spectrum egcwele ngu-200 eV kanye ne-spectrum encane ingu-50 eV. Isampula yempushana icindezelwa esibambi sesampula, esifakwa kugumbi lokuhlanza. I-spectrum ye-C 1 isetshenziswe njengereferensi ku-284.58 eV ukuze kunqunywe amandla okubopha.
Ukuhlolwa kwe-Adsorption kwenziwa ukuze kuhlolwe ukusebenza kahle kwe-rGO/nZVI nanocomposites ehlanganisiwe ekukhipheni i-doxycycline (DC) ezixazululweni ezinamanzi. Ukuhlolwa kwe-Adsorption kwenziwa kumaflaski angu-25 ml Erlenmeyer ngesivinini esinyakazayo esingu-200 rpm ku-orbital shaker (Stuart, Orbital Shaker/SSL1) ku-298 K. Ngokuhlambulula isisombululo sesitoko se-DC (1000 ppm) ngamanzi afakwe i-bidistilled. Ukuze kuhlolwe umphumela womthamo we-rGO/nSVI ekusebenzeni kahle kwe-adsorption, ama-nanocomposites ezisindo ezihlukene (0.01–0.07 g) angezwe ku-20 ml wesisombululo se-DC. Ukuze ufunde i-kinetics kanye ne-adsorption isotherm, i-0.05 g ye-adsorbent yacwiliswa kusisombululo esimanzi se-CD ngokugxilisa kokuqala (25-100 mg L-1). Umthelela we-pH ekukhishweni kwe-DC wacwaningwa ku-pH (3–11) kanye nokugxila kokuqala kuka-50 mg L-1 ku-25°C. Lungisa i-pH yesistimu ngokungeza inani elincane le-HCl noma isixazululo se-NaOH (imitha ye-Crison pH, imitha ye-pH, i-pH 25). Ngaphezu kwalokho, kuphenywe umthelela wezinga lokushisa lokusabela ekuhlolweni kwe-adsorption ebangeni lika-25-55°C. Umthelela wamandla e-ionic kunqubo ye-adsorption wacwaningwa ngokungeza ukugxila okuhlukahlukene kwe-NaCl (0.01–4 mol L–1) ekuhlanganiseni kokuqala kwe-DC ka-50 mg L–1, pH 3 kanye no-7), 25°C, kanye umthamo we-adsorbent ngu-0.05 g. I-adsorption ye-DC engafakwanga i-adsorbed ikalwe kusetshenziswa i-spectrophotometer ye-UV-Vis ekabili (uchungechunge lwe-T70/T80, i-PG Instruments Ltd, UK) ifakwe ama-cuvettes e-quartz ubude bendlela engu-1.0 cm kumaza amaza aphezulu (λmax) angu-270 no-350 nm. Iphesenti lokususwa kwemithi elwa namagciwane e-DC (R%; Eq. 1) kanye nenani le-adsorption le-DC, qt, Eq. 2 (mg/g) ikalwe kusetshenziswa isibalo esilandelayo.
lapho i-%R ingumthamo wokususwa kwe-DC (%), i-Co iwuphawu lokuqala lwe-DC ngesikhathi esingu-0, futhi u-C iwukugxilisa kwe-DC ngesikhathi t, ngokulandelanayo (mg L-1).
lapho u-qe kuyinani le-DC elikhangisiwe ngeyunithi yesisindo se-adsorbent (mg g-1), i-Co kanye ne-Ce kukhona ukugxilisa ingqondo ngesikhathi esinguziro nangokulingana, ngokulandelanayo (mg l-1), V iyivolumu yesixazululo (l) , futhi m yi-adsorption mass reagent (g).
Izithombe ze-SEM (Amakhiwane 2A–C) abonisa i-lamellar morphology yenhlanganisela ye-rGO/nZVI eneziyingi eziyindilinga nanoparticles ehlakazeke ngokufana ebusweni bayo, okubonisa ukunamathiselwe ngempumelelo kwe-nZVI NP endaweni ye-rGO. Ngaphezu kwalokho, kukhona imibimbi eqabungeni le-rGO, eqinisekisa ukususwa kwamaqembu aqukethe umoya-mpilo kanye kanye nokubuyiselwa kwe-A. halimus GO. Le mibimbi emikhulu isebenza njengezindawo zokulayisha okusebenzayo kwama-NPs ensimbi. Izithombe ze-nZVI (I-Fig. 2D-F) zibonise ukuthi ama-NP ensimbi ayindilinga ayehlakazeke kakhulu futhi awazange ahlanganiswe, okubangelwa ukumbozwa kwezingxenye zebhotani zesitshalo. Ubukhulu bezinhlayiyana buhluka phakathi kuka-15-26 nm. Kodwa-ke, ezinye izifunda zine-mesoporous morphology enesakhiwo samaqhuqhuva nezimbotshana, ezinganikeza amandla aphezulu wokukhangisa we-NZVI, ngoba zingakhuphula amathuba okubamba ama-molecule e-DC ebusweni be-NZVI. Lapho ukukhishwa kwe-Rosa Damaseku kusetshenziselwa ukuhlanganiswa kwe-nZVI, ama-NP atholiwe ayengenayo i-homogeneous, ane-voids kanye nokubunjwa okuhlukile, okunciphisa ukusebenza kahle kwawo ku-Cr(VI) adsorption futhi andisa isikhathi sokuphendula i-23. Imiphumela iyahambisana ne-nZVI ehlanganiswe namaqabunga e-oki nekamalibhele, ikakhulukazi ama-nanoparticles ayindilinga anosayizi abahlukahlukene be-nanometer ngaphandle kwe-agglomeration esobala.
Izithombe ze-SEM zenhlanganisela ye-rGO/nZVI (AC), nZVI (D, E) kanye namaphethini e-EDX wezinhlanganisela ze-nZVI/rGO (G) kanye ne-nZVI (H).
Ukwakheka okuyisisekelo kwezinhlanganisela ze-rGO/nZVI kanye ne-nZVI ezihlanganiswe nezitshalo kwacwaningwa kusetshenziswa i-EDX (I-Fig. 2G, H). Ucwaningo lubonisa ukuthi i-NZVI yakhiwe ngekhabhoni (38.29% ngobuningi), umoya-mpilo (47.41% ngobuningi) kanye nensimbi (11.84% ngobuningi), kodwa ezinye izakhi ezifana ne-phosphorus24 nazo zikhona, ezingatholakala ezikhishwe ezitshalweni. Ukwengeza, iphesenti eliphezulu lekhabhoni nomoya-mpilo libangelwa ukuba khona kwamakhemikhali e-phytochemicals avela ezitshalweni ezikhishwe kumasampuli angaphansi komhlaba we-NZVI. Lezi zakhi zisatshalaliswa ngokulinganayo ku-rGO kodwa ngezilinganiso ezihlukene: C (39.16 wt %), O (46.98 wt %) kanye ne-Fe (10.99 wt %), i-EDX rGO/nZVI iphinda ibonise ubukhona bezinye izici ezifana no-S, okuyinto zingahlotshaniswa nezitshalo ezikhishwe, zisetshenziswa. Isilinganiso samanje se-C:O nokuqukethwe kwensimbi kuyinhlanganisela ye-rGO/nZVI kusetshenziswa i-A. halimus singcono kakhulu kunokusebenzisa iqabunga likagamthilini, njengoba libonisa ukwakheka kuka-C (23.44 wt.%), O (68.29 wt.%) kanye no-Fe (8.27 wt.%). wt %) 25. U-Nataša et al., 2022 ubike ukwakheka okufanayo okuyisisekelo kwe-nZVI okuhlanganiswe emaqabunga e-oki nekamalibhele futhi kwaqinisekisa ukuthi amaqembu e-polyphenol namanye ama-molecule aqukethwe kusiqephu seqabunga anesibopho senqubo yokunciphisa.
I-morphology ye-NZVI ehlanganiswe ezitshalweni (I-Fig. S2A,B) yayiyindilinga futhi yayingajwayelekile ngokwengxenye, inosayizi wezinhlayiyana omaphakathi ongu-23.09 ± 3.54 nm, nokho amaketango ahlanganisiwe abonwa ngenxa yamandla e-van der Waals kanye ne-ferromagnetism. Lo mumo wezinhlayiyana eziwumbudumbudu kanye nendilinga uvumelana kahle nemiphumela ye-SEM. Ukuqaphela okufanayo kwatholwa ngu-Abdelfatah et al. ngo-2021 lapho kusetshenziswa iqabunga likabhontshisi we-castor ekuhlanganiseni kwe-nZVI11. I-Ruelas tuberosa leaf ikhiphe ama-NP asetshenziswa njenge-ejenti yokunciphisa ku-nZVI futhi anomumo oyindilinga onobubanzi obungu-20 kuya ku-40 nm26.
Izithombe ze-TEM ezihlanganisiwe ze-rGO/nZVI (I-Fig. S2C-D) zibonise ukuthi i-rGO iyindiza ye-basal egoqeka eceleni kanye nemibimbi enikeza amasayithi amaningi okulayisha ama-NZVI NP; le morphology ye-lamellar iphinde iqinisekise ukwenziwa ngempumelelo kwe-rGO. Ngaphezu kwalokho, ama-NZVI NP anesimo esiyindilinga esinosayizi bezinhlayiyana kusuka ku-5.32 kuya ku-27 nm futhi ashumekwe kungqimba lwe-rGO ngokuhlakazeka okucishe kufane. I-eucalyptus leaf extract yasetshenziselwa ukuhlanganiswa kwe-Fe NPs/rGO; Imiphumela ye-TEM iphinde yaqinisekisa ukuthi imibimbi kungqimba lwe-rGO ithuthukise ukusakazeka kwama-Fe NPs ngaphezu kwama-Fe NP ahlanzekile futhi yandisa ukusebenza kabusha kwezinhlanganisela. Imiphumela efanayo yatholwa ngu-Bagheri et al. 28 lapho inhlanganisela yenziwa kusetshenziswa amasu e-ultrasonic anesilinganiso sosayizi we-iron nanoparticle ongaba ngu-17.70 nm.
I-spectra ye-FTIR ye-A. halimus, nZVI, GO, rGO, kanye nenhlanganisela ye-rGO/nZVI iboniswa kumakhiwane. 3A. Ukuba khona kwamaqembu asebenza phezulu emaqabunga e-A. halimus kubonakala ku-3336 cm-1, okuhambisana ne-polyphenols, kanye ne-1244 cm-1, ehambisana namaqembu e-carbonyl akhiqizwa amaprotheni. Amanye amaqembu afana nama-alkanes ku-2918 cm-1, ama-alkenes ku-1647 cm-1 kanye nezandiso ze-CO-O-CO ku-1030 cm-1 abuye abonwa, ephakamisa ukuba khona kwezingxenye zezitshalo ezisebenza njengama-sealing agents futhi anesibopho sokululama. kusuka ku-Fe2+ kuye ku-Fe0 futhi GO ku-rGO29. Ngokuvamile, ukubukwa kwe-nZVI kukhombisa ukumunca okufanayo okuphakeme njengoshukela obabayo, kodwa ngokushintshashintsha kancane. Ibhande eliqinile livela ku-3244 cm-1 elihlotshaniswa nokudlidliza kwe-OH (phenols), inani eliphakeme ku-1615 lihambisana ne-C=C, futhi amabhendi aku-1546 kanye no-1011 cm-1 aphakama ngenxa yokwelula kwe-C=O (ama-polyphenols nama-flavonoids) , Amaqembu e-CN -ama-amine anephunga elimnandi nama-amine aliphatic nawo abonwa ku-1310 cm-1 no-1190 cm-1, ngokulandelana13. I-spectrum ye-FTIR ye-GO ibonisa ukuba khona kwamaqembu amaningi aqukethe umoya-mpilo onamandla amaningi, okuhlanganisa ibhendi enwebekayo ye-alkoxy (CO) ku-1041 cm-1, ibhendi enwebekayo ye-epoxy (CO) ku-1291 cm-1, C=O stretch. ibhendi ye-C=C enwebekayo yokudlidliza ku-1619 cm-1, ibhendi eku-1708 cm-1 kanye nebhendi ebanzi yeqembu le-OH elelula ukudlidliza ku-3384 cm-1 livele, okuqinisekiswa indlela ye-Hummers ethuthukisiwe, eyenza ngempumelelo i-oxidize inqubo ye-graphite. Uma kuqhathaniswa izinhlanganisela ze-rGO ne-rGO/nZVI ne-GO spectra, ukuqina kwamanye amaqembu aqukethe umoya-mpilo, njenge-OH ku-3270 cm-1, kuncipha kakhulu, kuyilapho amanye, njenge-C=O ku-1729 cm-1, ancipha ngokuphelele. kuncishisiwe. inyamalala, okubonisa ukususwa ngempumelelo kwamaqembu asebenzayo aqukethe umoya-mpilo ku-GO ngokukhishwa kwe-A. halimus. Iziqongo ezintsha ezicijile ze-rGO ku-C=C ukungezwani zibonwa cishe ku-1560 kanye no-1405 cm-1, okuqinisekisa ukuncishiswa kwe-GO ku-rGO. Ukuhlukahluka kusuka ku-1043 kuya ku-1015 cm-1 futhi kusukela ku-982 kuya ku-918 cm-1 kwabonwa, mhlawumbe ngenxa yokufakwa kwezinto zezitshalo31,32. Weng et al., 2018 baphinde babona ukuncishiswa okukhulu kwamaqembu asebenza nge-oksijini ku-GO, okuqinisekisa ukwakheka ngempumelelo kwe-rGO ngokuncishiswa kwe-bioreduction, njengoba izingcaphuno zeqabunga likagamthilini, ezazisetshenziselwa ukuhlanganisa izinhlanganisela zensimbi ezincishisiwe ze-iron graphene oxide, zibonise i-spectra ye-FTIR eseduze yengxenye yesitshalo. amaqembu asebenzayo. 33 .
A. I-FTIR spectrum ye-gallium, i-nZVI, rGO, GO, inhlanganisela ye-rGO/nZVI (A). I-Roentgenogrammy ihlanganisa u-rGO, GO, nZVI kanye no-rGO/nZVI (B).
Ukwakhiwa kwezinhlanganisela ze-rGO/nZVI kanye ne-NZVI kwaqinisekiswa kakhulu amaphethini okushintshashintsha kwe-X-ray (Fig. 3B). Ukuphakama okuphezulu kwe-Fe0 kubonwe ku-2Ɵ 44.5°, okuhambisana nenkomba (110) (JCPDS no. 06–0696)11. Okunye ukuphakama kwendiza engu-35.1 ° ye-(311) kuthiwa yi-magnetite Fe3O4, i-63.2 ° ingase ihlotshaniswe ne-Miller index yendiza (440) ngenxa yokuba khona kwe-ϒ-FeOOH (JCPDS no. 17-0536)34. Iphethini ye-X-ray ye-GO ibonisa ukuphakama okucijile ku-2Ɵ 10.3° nesinye isiqongo esingu-21.1°, okubonisa ukucwecwa okuphelele kwegraphite nokugqamisa ukuba khona kwamaqembu aqukethe umoya-mpilo ebusweni be-GO35. Amaphethini ayinhlanganisela we-rGO ne-rGO/nZVI aqophe ukunyamalala kweziqongo ze-GO kanye nokwakheka kweziqongo ezibanzi ze-rGO ku-2Ɵ 22.17 kanye no-24.7° kuzinhlanganisela ze-rGO kanye ne-rGO/nZVI, ngokulandelana, okuqinisekisa ukutholwa okuyimpumelelo kwe-GO ngokukhipha izitshalo. Nokho, kuphethini eyinhlanganisela ye-rGO/nZVI, iziqongo ezengeziwe ezihlobene nendiza ye-lattice ye-Fe0 (110) kanye ne-bcc Fe0 (200) zibonwe kokuthi 44.9\(^\circ\) kanye no-65.22\(^\circ\), ngokulandelanayo. .
Amandla e-zeta amandla aphakathi kongqimba lwe-ionic olunamathiselwe ebusweni bezinhlayiyana kanye nesisombululo esinamanzi esinquma izici ze-electrostatic zento futhi sikala ukuzinza kwayo37. Ukuhlaziywa okunamandla kwe-Zeta kwezinhlanganisela ze-nZVI, GO, kanye ne-rGO/nZVI ezitshaliwe kubonise ukuzinza kwazo ngenxa yokuba khona kwamacala amabi -20.8, -22, kanye -27.4 mV, ngokulandelana, ebusweni bazo, njengoba kuboniswe kuMfanekiso S1A- C. . Imiphumela enjalo ihambisana nemibiko eminingana esho ukuthi izixazululo eziqukethe izinhlayiya ezinamavelu angaba khona we-zeta angaphansi kuka- -25 mV ngokuvamile zibonisa izinga eliphezulu lokuzinza ngenxa yokwehliswa kwe-electrostatic phakathi kwalezi zinhlayiya. Inhlanganisela ye-rGO ne-nZVI ivumela inhlanganisela ukuthi ithole izinkokhelo ezingezinhle futhi ngaleyo ndlela ibe nokuzinza okuphezulu kune-GO noma i-NZVI iyodwa. Ngakho-ke, ukwenzeka kwe-electrostatic repulsion kuzoholela ekwakhekeni kwezinhlanganisela ze-rGO/nZVI39 ezizinzile. Indawo engalungile ye-GO ivumela ukuthi ihlakazwe ngokulinganayo endaweni enamanzi ngaphandle kokuhlanganiswa, okudala izimo ezivumayo zokusebenzelana ne-NZVI. Inkokhelo engeyinhle ingase ihlotshaniswe nokuba khona kwamaqembu ahlukene asebenzayo ekukhishweni kwekhabe elibabayo, okuqinisekisa futhi ukusebenzisana phakathi kwe-GO ne-iron precursors kanye nokukhipha kwesitshalo ukwenza i-rGO ne-nZVI, ngokulandelana, kanye ne-rGO/nZVI complex. Lezi zinhlanganisela zezitshalo nazo zingasebenza njengama-agent we-capping, njengoba zivimbela ukuhlanganiswa kwe-nanoparticles ephumela futhi ngaleyo ndlela zandise ukuzinza kwazo40.
Ukwakheka okuyisisekelo nezimo ze-valence zenhlanganisela ye-nZVI kanye ne-rGO/nZVI kunqunywe yi-XPS (Fig. 4). Ucwaningo lwe-XPS lulonke lubonise ukuthi inhlanganisela ye-rGO/nZVI yakhiwe ngokuyinhloko izici C, O, kanye no-Fe, ezihambisana nokumepha kwe-EDS (Fig. 4F–H). I-spectrum ye-C1s iqukethe iziqongo ezintathu ku-284.59 eV, 286.21 eV kanye no-288.21 eV abamele i-CC, CO kanye ne-C=O, ngokulandelanayo. I-spectrum ye-O1s yahlukaniswa yaba iziqongo ezintathu, okuhlanganisa i-531.17 eV, 532.97 eV, kanye ne-535.45 eV, eyabelwa amaqembu e-O=CO, CO, kanye NO-NO, ngokulandelanayo. Nokho, iziqongo ku-710.43, 714.57 kanye ne-724.79 eV zibhekisela ku-Fe 2p3/2, Fe+3 kanye no-Fe p1/2, ngokulandelanayo. I-spectra ye-XPS ye-nZVI (Fig. 4C-E) ibonise iziqongo zama-elementi C, O, no-Fe. Iziqongo ku-284.77, 286.25, kanye ne-287.62 eV ziqinisekisa ubukhona be-iron-carbon alloys, njengoba zibhekisela ku-CC, C-OH, ne-CO, ngokulandelanayo. I-spectrum ye-O1s ihambisana neziqongo ezintathu ze-C–O/iron carbonate (531.19 eV), i-hydroxyl radical (532.4 eV) kanye ne-O–C=O (533.47 eV). Ukuphakama okungu-719.6 kuthiwa kubangelwa i-Fe0, kuyilapho i-FeOOH ibonisa ukuphakama kokungu-717.3 no-723.7 eV, ngaphezu kwalokho, ukuphakama okungu-725.8 eV kubonisa ukuba khona kwe-Fe2O342.43.
Izifundo ze-XPS zezinhlanganisela ze-nZVI ne-rGO/nZVI, ngokulandelana kwazo (A, B). Ukubuka okuphelele kwe-nZVI C1s (C), Fe2p (D), kanye ne-O1s (E) kanye nenhlanganisela ye-rGO/nZVI C1s (F), Fe2p (G), O1s (H).
I-N2 adsorption/desorption isotherm (Fig. 5A, B) ibonisa ukuthi izinhlanganisela ze-NZVI kanye ne-rGO/nZVI ziyingxenye yohlobo II. Ngaphezu kwalokho, indawo ethile (i-SBET) ye-nZVI inyuke isuka ku-47.4549 yaya ku-152.52 m2/g ngemva kokuphuphuthekisa nge-rGO. Lo mphumela ungachazwa ukwehla kwezakhiwo kazibuthe ze-NZVI ngemuva kokuphuphuthekisa kwe-rGO, ngaleyo ndlela kunciphisa ukuhlangana kwezinhlayiyana futhi kwandise indawo engaphezulu yezinhlanganisela. Ngaphezu kwalokho, njengoba kuboniswe ku-Fig. 5C, ivolumu yembotshana (8.94 nm) yenhlanganisela ye-rGO/nZVI iphakeme kunaleyo ye-nZVI yasekuqaleni (2.873 nm). Lo mphumela uvumelana no-El-Monaem et al. 45 .
Ukuze kuhlolwe umthamo we-adsorption wokukhipha i-DC phakathi kwezinhlanganisela ze-rGO/nZVI kanye ne-nZVI yoqobo kuye ngokwanda kokugxilisa ingqondo kokuqala, ukuqhathanisa kwenziwe ngokungeza umthamo ongashintshi we-adsorbent ngayinye (0.05 g) ku-DC ekugxiliseni okuhlukile kokuqala. Isixazululo esiphenyiwe [25]. -100 mg l–1] ku-25°C. Imiphumela yabonisa ukuthi ukusebenza kahle kokususa (94.6%) kwenhlanganisela ye-rGO/nZVI kwakungaphezulu kwalokho kwe-nZVI yasekuqaleni (90%) ekugxilweni okuphansi (25 mg L-1). Kodwa-ke, lapho ukugxila kokuqala kukhushulwa ku-100 mg L-1, ukusebenza kahle kokususwa kwe-rGO/nZVI kanye ne-NZVI yabazali kwehle kwaya ku-70% no-65% ngokulandelana (Umfanekiso 6A), okungenzeka kube ngenxa yokuncipha kwezindawo ezisebenzayo kanye nokuwohloka kwe izinhlayiya ze-nZVI. Ngokuphambene, i-rGO/nZVI ibonise ukusebenza kahle okuphezulu kokususwa kwe-DC, okungenzeka kungenxa yomphumela wokusebenzisana phakathi kwe-rGO ne-nZVI, lapho izingosi ezisebenzayo ezitholakalayo zokukhangisa ziphakeme kakhulu, futhi esimweni se-rGO/nZVI, ngaphezulu I-DC ingakhangiswa kune-nZVI engaguquki. Ngaphezu kwalokho, emkhiwaneni. I-6B ikhombisa ukuthi umthamo wokukhangiswa wezinhlanganisela ze-rGO/nZVI ne-NZVI wenyuka usuka ku-9.4 mg/g waya ku-30 mg/g no-9 mg/g, ngokulandelana, nokwanda kokuhlushwa kokuqala kusuka ku-25–100 mg/L. -1.1 kuya ku-28.73 mg g-1. Ngakho-ke, izinga lokususwa kwe-DC lalihlotshaniswa kabi nokugxiliswa kwe-DC kokuqala, okwakubangelwe inombolo elinganiselwe yezikhungo zokusabela ezisekelwa i-adsorbent ngayinye yokukhangisa nokususwa kwe-DC esixazululweni. Ngakho-ke, kungaphethwa kusuka kule miphumela ukuthi izinhlanganisela ze-rGO/nZVI zinokusebenza okuphezulu kwe-adsorption nokunciphisa, futhi i-rGO ekubunjweni kwe-rGO/nZVI ingasetshenziswa kokubili njenge-adsorbent nanjengento yenkampani yenethiwekhi.
Ukusebenza kahle kokususa kanye nomthamo we-DC wokukhangisa wenhlanganisela ye-rGO/nZVI kanye ne-NZVI bekungu-(A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, umthamo = 0.05 g], pH. kumthamo we-adsorption kanye nokusebenza kahle kokususwa kwe-DC kuzinhlanganisela ze-rGO/nZVI (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, umthamo = 0.05 g].
Isixazululo i-pH iyisici esibalulekile ocwaningweni lwezinqubo ze-adsorption, njengoba sithinta izinga le-ionization, i-speciation, ne-ionization ye-adsorbent. Ukuhlolwa kwenziwe ku-25°C ngedosi ye-adsorbent engashintshi (0.05 g) kanye nokuhlushwa kokuqala kuka-50 mg L-1 ebangeni le-pH (3–11). Ngokusho kokubuyekezwa kwezincwadi46, i-DC iyi-amphiphilic molecule enamaqembu amaningana asebenzayo e-ionzable (ama-phenols, amaqembu e-amino, utshwala) kumazinga ahlukahlukene we-pH. Njengomphumela, imisebenzi eyahlukene ye-DC kanye nezakhiwo ezihlobene endaweni eyinhlanganisela ye-rGO/nZVI ingase ihlanganyele ngogesi futhi ingase ibe khona njengama-cations, ama-zwitterion, nama-anions, i-molecule ye-DC ikhona njenge-cationic (DCH3+) ku-pH <3.3, I-zwitterionic (DCH20) 3.3 < pH < 7.7 kanye ne-anionic (DCH− noma i-DC2−) kokuthi PH 7.7. Njengomphumela, imisebenzi eyahlukene ye-DC kanye nezakhiwo ezihlobene endaweni eyinhlanganisela ye-rGO/nZVI ingase ihlanganyele ngogesi futhi ingase ibe khona njengama-cations, ama-zwitterion, nama-anions, i-molecule ye-DC ikhona njenge-cationic (DCH3+) ku-pH <3.3, I-zwitterionic (DCH20) 3.3 < pH <7.7 kanye ne-anionic (DCH- noma i-DC2-) kokuthi PH 7.7. В результате различные функции ДК и связанных с ними структур на поверхности композита пункции ДК и связанных с ними структур на поверхности композита в заимодействовать электровать электровие нов, цвиттер-ионов и анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер- i-онный (DCH20) 3,3 < pH < 7,7 and анионный (DCH- или DC2-) при pH 7,7. Ngenxa yalokho, imisebenzi ehlukahlukene ye-DC kanye nezakhiwo ezihlobene endaweni eyinhlanganisela ye-rGO/nZVI ingasebenzisana ngendlela yogesi futhi ingaba khona ngendlela yama-cation, ama-zwitterion, nama-anions; i-molecule ye-DC ikhona njenge-cation (DCH3+) ku-pH <3.3; ionic (DCH20) 3.3 < pH <7.7 kanye ne-anionic (DCH- noma i-DC2-) ku-pH 7.7.因此，DC 的各子子种功能和rGO/nZVI 复合材料表面的相关结构可能会发生黙电相互作用，并离开形式存在，DC 分子在pH <3.3 时以阳离子(DCH3+) 的形式存在，两性离子(DCH20) 3.3 <pH <7.7 和阴离子(DCH- 或DC2-) 在PH 7.7.因此 , dc 子的 种 功能 和 和 和 复合 材料 表面 的相关 结构 可能 发生 静生 静生 相关 结构性 和 阴离子 形式 ， dc 分子 在 pH <3.3 时 阳离子 阳离子 阳离子 阳离子 (dch3+)形式存在，两性离子(DCH20) 3.3 <pH <7.7 和阴离子(DCH- 或DC2-) 在PH 7.7. Следовательно, различные функции ДК и родственных им структур на поверхности композита rGO/nZVI могут вступать вступать вступать вступать вступать вступать вступать вступать вступать вступать вступать вступать им катионов, цвиттер-ионов и анионов, а молекулы ДК являются катионными (ДЦГ3+) при рН < 3,3. Ngakho-ke, imisebenzi eyahlukene ye-DC nezakhiwo ezihlobene endaweni eyinhlanganisela ye-rGO/nZVI ingangena ekusebenzisaneni kwe-electrostatic futhi ibe khona ngendlela yama-cations, ama-zwitterion, nama-anions, kuyilapho ama-molecule e-DC eyi-cationic (DCH3+) ku-pH <3.3. Он существует в виде цвиттер-иона (DCH20) при 3,3 < pH < 7,7 and аниона (DCH- или DC2-) при pH 7,7. Itholakala njenge-zwitterion (DCH20) ku-3.3 <pH <7.7 kanye ne-anion (DCH- noma i-DC2-) ku-pH 7.7.Ngokunyuka kwe-pH kusuka ku-3 kuya ku-7, umthamo we-adsorption nokusebenza kahle kokususwa kwe-DC kukhuphuke kusuka ku-11.2 mg/g (56%) kuya ku-17 mg/g (85%) (Fig. 6C). Kodwa-ke, njengoba i-pH inyuka yaba ngu-9 no-11, amandla okukhangisa nokusebenza kahle kokususa kwehle ngandlela thize, ukusuka ku-10.6 mg/g (53%) kuya ku-6 mg/g (30%), ngokulandelana. Ngokukhuphuka kwe-pH isuka ku-3 iye ku-7, ama-DCs abekhona ikakhulukazi ngendlela yama-zwitterion, awenza acishe aheheka ngokungasebenzisi ugesi noma enyanyiswa ngezinhlanganisela ze-rGO/nZVI, ikakhulukazi ngokusebenzisana kwe-electrostatic. Njengoba i-pH inyuka ngaphezu kuka-8.2, ingaphezulu le-adsorbent lakhokhiswa kabi, ngaleyo ndlela amandla e-adsorption ehla futhi ehla ngenxa ye-electrostatic repulsion phakathi kwe-doxycycline eshajiwe kabi kanye nengaphezulu le-adsorbent. Le threndi iphakamisa ukuthi ukukhangisa kwe-DC kuzinhlanganisela ze-rGO/nZVI kuncike kakhulu ku-pH, futhi imiphumela iphinda ibonise ukuthi izinhlanganisela ze-rGO/nZVI zifaneleka njengama-adsorbent ngaphansi kwezimo ezine-asidi nezimaphakathi.
Umphumela wokushisa ekukhangiseni kwesisombululo esinamanzi se-DC wenziwa ku-(25-55°C). Umfanekiso 7A ubonisa umthelela wokukhuphuka kwezinga lokushisa ekusebenzeni kahle kokukhipha ama-antibiotic e-DC ku-rGO/nZVI, kusobala ukuthi amandla okususa namandla e-adsorption anyuke esuka ku-83.44% kanye no-13.9 mg/g kuya ku-47% kanye no-7.83 mg/g. , ngokulandelana. Lokhu kuncipha okuphawulekayo kungase kube ngenxa yokwanda kwamandla okushisa ama-ion e-DC, okuholela e-desorption47.
Umthelela Wezinga lokushisa Ekususeni Kahle kanye Nomthamo Wokukhangisa we-CD ku-rGO/nZVI Composites (A) [Co = 50 mg L–1, pH = 7, Dose = 0.05 g], Idosi Ye-Adsorbent Ekususeni Kahle kanye Nokususwa Kahle KweCD Umphumela we- Ukugxila Kwasekuqaleni kumthamo we-adsorption nokusebenza kahle kokususwa kwe-DC kunhlanganisela 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-adsorbent eyinhlanganisela rGO/nZVI ukusuka ku-0.01 g ukuya ku-0.07 g ekusebenzeni kahle kokususa kanye namandla okukhangisa kuboniswa ku-Fig. 7B. Ukwenyuka komthamo we-adsorbent kuholele ekwehleni komthamo we-adsorption kusuka ku-33.43 mg/g kuya ku-6.74 mg/g. Kodwa-ke, ngokukhuphuka komthamo we-adsorbent kusuka ku-0.01 g kuya ku-0.07 g, ukusebenza kahle kokususa kukhuphuka kusuka ku-66.8% kuya ku-96%, okuthi, ngokufanele, kuhlotshaniswe nokwanda kwenani lezikhungo ezisebenzayo endaweni ye-nanocomposite.
Umphumela wokugxila kokuqala kumthamo we-adsorption nokusebenza kahle kokususa [25-100 mg L-1, 25°C, pH 7, dose 0.05 g] wacwaningwa. Lapho ukugxila kokuqala kunyuswa kusuka ku-25 mg L-1 kuya ku-100 mg L-1, amaphesenti okususwa kwenhlanganisela ye-rGO/nZVI yehla ukusuka ku-94.6% yaya ku-65% (Fig. 7C), mhlawumbe ngenxa yokungabikho kokusebenza okufunayo. amasayithi. . I-Adsorbs ukugxila okukhulu kwe-DC49. Ngakolunye uhlangothi, njengoba ukuhlushwa kokuqala kwanda, umthamo we-adsorption nawo wanda kusuka ku-9.4 mg / g kuya ku-30 mg / g kuze kufike ukulingana (Fig. 7D). Lokhu kusabela okungenakugwemeka kungenxa yokwanda kwamandla okushayela ngokugxiliswa kwe-DC kokuqala okukhulu kunokumelana nokudluliselwa kwe-ion mass ye-DC ukuze kufinyelelwe endaweni engu-50 yenhlanganisela ye-rGO/nZVI.
Isikhathi sokuxhumana kanye nezifundo ze-kinetic zihlose ukuqonda isikhathi sokulinganisa se-adsorption. Okokuqala, inani le-DC elikhangisiwe phakathi nemizuzu yokuqala engu-40 yesikhathi sokuxhumana lalicishe libe uhhafu yenani eliphelele elikhangisiwe ngaso sonke isikhathi (imizuzu eyi-100). Ngenkathi ama-molecule e-DC asesisombululo eshayisana okuwenza afudukele ngokushesha endaweni eyinhlanganisela ye-rGO/nZVI okuholela ekukhangisweni okubalulekile. Ngemva kwemizuzu engu-40, i-DC adsorption yanda kancane kancane futhi kancane kancane kuze kube yilapho ukulingana kufinyelelwa ngemva kwemizuzu engu-60 (Fig. 7D). Njengoba inani elizwakalayo likhangiswa emizuzwini yokuqala engu-40, kuzoba nokushayisana okumbalwa nama-molecule e-DC futhi amasayithi asebenzayo ambalwa azotholakala kuma-molecule angenawo ama-adsorbed. Ngakho-ke, izinga le-adsorption lingancishiswa51.
Ukuze uqonde kangcono i-adsorption kinetics, iziqephu zomugqa we-pseudo oda lokuqala (Fig. 8A), i-pseudo order yesibili (Fig. 8B), kanye ne-Elovich (Fig. 8C) amamodeli e-kinetic asetshenzisiwe. Kusukela kumapharamitha atholwe ezifundweni zekinetic (Ithebula S1), kuyacaca ukuthi imodeli ye-pseudosecond iyimodeli engcono kakhulu yokuchaza i-adsorption kinetics, lapho inani le-R2 libekwe phezulu kunamanye amamodeli amabili. Kukhona futhi ukufana phakathi kwamakhono e-adsorption abaliwe (qe, cal). I-oda lesibili-mbumbulu kanye namanani okuhlola (qe, exp.) kuwubufakazi obengeziwe bokuthi i-oda lesibili-mbumbulu liyimodeli engcono kunamanye amamodeli. Njengoba kuboniswe kuThebula 1, amanani ka-α (isilinganiso sokuqala sokukhangiswa) kanye no-β (i-desorption constant) aqinisekisa ukuthi izinga le-adsorption liphezulu kune-desorption rate, okubonisa ukuthi i-DC ivamise ukukhangisa kahle kwinhlanganisela ye-rGO/nZVI52. .
I-Linear adsorption kinetic plots of pseudo-second order (A), pseudo-first order (B) kanye ne-Elovich (C) [Co = 25–100 mg l–1, pH = 7, T = 25 °C, umthamo = 0.05 g ].
Izifundo zama-adsorption isotherms zisiza ukucacisa umthamo we-adsorption we-adsorbent (inhlanganisela ye-RGO/nRVI) ekugxilweni okuhlukahlukene kwe-adsorbate (DC) namazinga okushisa esistimu. Umthamo omkhulu we-adsorption ubalwa kusetshenziswa i-isotherm ye-Langmuir, ebonise ukuthi isikhangiso sasifana futhi sasihlanganisa ukwakheka kwe-adsorbate monolayer ebusweni be-adsorbent ngaphandle kokuxhumana phakathi kwabo53. Amanye amamodeli we-isotherm amabili asetshenziswa kakhulu yiFreundlich neTemkin. Nakuba imodeli ye-Freundlich ingasetshenziselwa ukubala umthamo we-adsorption, isiza ukuqonda inqubo ye-adsorption ehlukahlukene kanye nokuthi izikhala ku-adsorbent zinamandla ahlukene, kuyilapho imodeli ye-Temkin isiza ukuqonda izici zomzimba nezamakhemikhali ze-adsorption54.
Izibalo 9A-C zibonisa iziqephu zomugqa zamamodeli we-Langmuir, Freindlich, kanye ne-Temkin, ngokulandelanayo. Amanani e-R2 abalwe kusukela kusiqephu somugqa we-Freundlich (Fig. 9A) kanye ne-Langmuir (Fig. 9B) futhi ethulwe kuThebula 2 abonisa ukuthi i-adsorption ye-DC kwinhlanganisela ye-rGO/nZVI ilandela i-Freundlich (0.996) ne-Langmuir (0.988) isotherm (0.988) amamodeli kanye ne-Temkin (0.985). Umthamo omkhulu we-adsorption (qmax), obalwe kusetshenziswa imodeli ye-Langmuir isotherm, ubungu-31.61 mg g-1. Ngaphezu kwalokho, inani elibaliwe le-dimensionless separation factor (RL) liphakathi kuka-0 no-1 (0.097), okubonisa inqubo evumayo yokukhangisa. Uma kungenjalo, i-Freundlich engaguquki (n = 2.756) ikhombisa okuncamelayo kule nqubo yokumuncwa. Ngokwemodeli yomugqa ye-isotherm ye-Temkin (Fig. 9C), ukukhangiswa kwe-DC kwinhlanganisela ye-rGO/nZVI kuyinqubo yokukhangisa ebonakalayo, njengoba u-b engu-˂ 82 kJ mol-1 (0.408)55. Nakuba ukukhangiswa ngokomzimba kuvame ukulamula amandla abuthakathaka e-van der Waals, ukukhangisa kwamanje okuqondile kuzinhlanganisela ze-rGO/nZVI kudinga amandla aphansi e-adsorption [56, 57].
I-Freundlich (A), i-Langmuir (B), kanye ne-Temkin (C) i-isotherm ye-adsorption eqondile [Co = 25–100 mg L–1, pH = 7, T = 25 °C, umthamo = 0.05 g]. Isakhiwo sesibalo se-van't Hoff se-DC adsorption ngezinhlanganisela ze-rGO/nZVI (D) [Co = 25–100 mg l-1, pH = 7, T = 25–55 °C kanye nomthamo = 0.05 g].
Ukuze uhlole umthelela wokushintsha kwezinga lokushisa okusabelayo ekukhishweni kwe-DC kusukela kuzinhlanganisela ze-rGO/nZVI, amapharamitha we-thermodynamic afana noshintsho lwe-entropy (ΔS), ushintsho lwe-enthalpy (ΔH), noshintsho lwamahhala lwamandla (ΔG) abalwe kusukela ezilinganisweni. 3 ngo458.
lapho \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) - i-thermodynamic equilibrium constant, Ce and CAe – rGO in solution, ngokulandelana /nZVI DC ukugxila ekulinganeni kwendawo. I-R ne-RT izinga lokushisa legesi elingaguquki kanye ne-adsorption, ngokulandelanayo. Ukuceba i-ln Ke ngokumelene no-1/T kunikeza umugqa oqondile (Fig. 9D) lapho ∆S kanye no-∆H kunganqunywa khona.
Inani elingalungile le-ΔH libonisa ukuthi inqubo i-exothermic. Ngakolunye uhlangothi, inani le-ΔH lingaphakathi kwenqubo ye-adsorption ebonakalayo. Amanani e-ΔG anegethivu kuThebula 3 abonisa ukuthi ukukhangisa kuyenzeka futhi kuyazenzekela. Amanani angemihle we-ΔS abonisa ukuhleleka okuphezulu kwama-molecule e-adsorbent endaweni ewuketshezi (Ithebula 3).
Ithebula lesi-4 liqhathanisa inhlanganisela ye-rGO/nZVI nezinye izikhangisi ezibikwe ezifundweni ezedlule. Kuyacaca ukuthi inhlanganisela ye-VGO/nCVI inamandla okukhangisa aphezulu futhi ingase ibe yinto ethembisayo yokukhishwa kwama-antibiotic e-DC emanzini. Ngaphezu kwalokho, ukukhangisa kwezinhlanganisela ze-rGO/nZVI kuyinqubo esheshayo enesikhathi sokulinganisa esingamaminithi angu-60. Izici ezinhle kakhulu zokukhangisa zezinhlanganisela ze-rGO/nZVI zingachazwa ngomphumela we-synergistic we-rGO kanye ne-NZVI.
Izibalo 10A, B zibonisa indlela ephusile yokususwa kwemithi elwa namagciwane e-DC ngezinhlanganisela ze-rGO/nZVI kanye ne-nZVI. Ngokwemiphumela yokuhlolwa komthelela we-pH ekusebenzeni kahle kwe-DC adsorption, ngokwenyuka kwe-pH isuka ku-3 iye ku-7, ukukhangisa kwe-DC kunhlanganisela ye-rGO/nZVI ayizange ilawulwe ukusebenzisana kwe-electrostatic, ngoba yenza njengezwitterion; ngakho-ke, ukuguqulwa kwenani le-pH akuzange kuthinte inqubo ye-adsorption. Ngokulandelayo, indlela ye-adsorption ingalawulwa ukusebenzisana okungeyona i-electrostatic efana ne-hydrogen bonding, imiphumela ye-hydrophobic, kanye nokusebenzelana kokunqwabelanisa okungu-π-π phakathi kwenhlanganisela ye-rGO/nZVI ne-DC66. Kwaziwa kahle ukuthi indlela ye-adsorbates enamakha endaweni ye-graphene enezingqimba ichazwe ukusebenzisana kokunqwabelanisa okungu-π–π njengamandla okushayela. Inhlanganisela iyisisetshenziswa esinezingqimba esifana ne-graphene enobuningi bokumuncwa ku-233 nm ngenxa yoguquko luka-π-π*. Ngokusekelwe ebukhoneni bamasongo amane anephunga elimnandi esakhiweni samangqamuzana e-DC adsorbate, sacabanga ukuthi kukhona indlela yokusebenzisana kuka-π-π-stacking phakathi kwe-DC enuka kamnandi (π-electron acceptor) kanye nesifunda esicebile ngama-electron angu-π. indawo ye-RGO. /nZVI izinhlanganisela. Ngaphezu kwalokho, njengoba kuboniswe emkhiwaneni. I-10B, izifundo ze-FTIR zenzelwe ukutadisha ukusebenzisana kwamangqamuzana enhlanganisela ye-rGO/nZVI ne-DC, kanye nombono we-FTIR wezinhlanganisela ze-rGO/nZVI ngemva kokukhangisa kwe-DC kuboniswa kuMfanekiso 10B. 10b. Ukuphakama okusha kubonwa ku-2111 cm-1, okuhambisana nokudlidliza kohlaka lwe-C=C bond, okubonisa ukuba khona kwamaqembu asebenzayo ahambisanayo ebusweni buka-67 rGO/nZVI. Ezinye iziqongo zisuka ku-1561 ziye ku-1548 cm-1 futhi zisuka ku-1399 ziye ku-1360 cm-1, okuqinisekisa futhi ukuthi ukusebenzisana kuka-π-π kudlala indima ebalulekile ekufakweni kwe-graphene nokungcola kwe-organic68,69. Ngemuva kwe-DC adsorption, ukuqina kwamanye amaqembu aqukethe umoya-mpilo, njenge-OH, lehla laya ku-3270 cm-1, okuphakamisa ukuthi i-hydrogen bonding ingenye yezindlela zokukhangisa. Ngakho, ngokusekelwe emiphumeleni, ukukhangiswa kwe-DC kwinhlanganisela ye-rGO/nZVI kwenzeka ikakhulukazi ngenxa yokusebenzisana kokunqwabelanisa kuka-π-π namabhondi e-H.
Indlela enengqondo yokukhangiswa kwemithi elwa namagciwane e-DC nge-rGO/nZVI kanye ne-nZVI complexes (A). I-FTIR adsorption spectra ye-DC ku-rGO/nZVI kanye ne-nZVI (B).
Ukuqina kwamabhendi okumuncwa we-NZVI ku-3244, 1615, 1546, kanye no-1011 cm–1 kukhuphuke ngemva kokukhangisa kwe-DC ku-NZVI (Fig. 10B) uma kuqhathaniswa ne-NZVI, okufanele ihlobane nokusebenzelana namaqembu asebenzayo e-carboxylic acid. O amaqembu ku-DC. Kodwa-ke, leli phesenti eliphansi lokudlulisela kuwo wonke amabhendi abhekiwe libonisa alukho ushintsho olubalulekile ekusebenzeni kahle kwe-adsorption ye-phytosynthetic adsorbent (nZVI) uma kuqhathaniswa ne-nZVI ngaphambi kwenqubo yokukhangisa. Ngokocwaningo oluthile lokususa lwe-DC olune-nZVI71, lapho i-nZVI iphendulana ne-H2O, ama-electron ayakhululwa bese i-H+ isetshenziselwa ukukhiqiza i-hydrogen esebenzayo eyehla kakhulu. Ekugcineni, ezinye izinhlanganisela ze-cationic zamukela ama-electron avela ku-hydrogen esebenzayo, okuholela ku- -C=N kanye -C=C-, okubangelwa ukuhlukana kweringi ye-benzene.
Isikhathi sokuthumela: Nov-14-2022