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Kulo msebenzi, ii-composites ze-rGO/nZVI zenziwe okokuqala kusetyenziswa inkqubo elula neyongamela okusingqongileyo kusetyenziswa i-Sophora yellow leaf extract njenge-reducing agent kunye ne-stabilizer ukuze kuhambelane nemigaqo ye-"green" chemistry, efana nokuhlanganiswa kweekhemikhali okungenabungozi kangako. Izixhobo ezininzi zisetyenzisiwe ukuqinisekisa ukuhlanganiswa okuphumelelayo kwee-composites, ezifana ne-SEM, EDX, XPS, XRD, FTIR, kunye ne-zeta potential, ezibonisa ukwenziwa okuphumelelayo kwe-composite. Amandla okususa ii-composites ezintsha kunye ne-nZVI ecocekileyo kumanqanaba ahlukeneyo okuqala e-antibiotic doxycycline athelekiswa nokuphanda isiphumo sokusebenzisana phakathi kwe-rGO kunye ne-nZVI. Phantsi kweemeko zokususa ze-25mg L-1, 25°C kunye ne-0.05g, izinga lokususa i-nZVI ecocekileyo yayiyi-90%, ngelixa izinga lokususa i-doxycycline nge-rGO/nZVI composite lifikelele kwi-94.6%, liqinisekisa ukuba i-nZVI kunye ne-rGO. Inkqubo yokufunxa ihambelana nomyalelo we-pseudo-second kwaye ihambelana kakuhle nemodeli yeFreundlich enomthamo ophezulu wokufunxa we-31.61 mg g-1 kwi-25 °C kunye ne-pH 7. Indlela efanelekileyo yokususa i-DC icetyisiwe. Ukongeza, ukusetyenziswa kwakhona kwe-rGO/nZVI composite yayiyi-60% emva kwemijikelo emithandathu elandelelanayo yokuvuselela.
Ukunqongophala kwamanzi kunye nongcoliseko ngoku zizinto ezisongela kakhulu kuwo onke amazwe. Kwiminyaka yakutshanje, ungcoliseko lwamanzi, ingakumbi ungcoliseko lwamayeza okubulala iintsholongwane, luye lwanda ngenxa yokwanda kwemveliso nokusetyenziswa ngexesha lobhubhane we-COVID-191,2,3. Ke ngoko, uphuhliso lwetekhnoloji esebenzayo yokuphelisa amayeza okubulala iintsholongwane emanzini amdaka ngumsebenzi ongxamisekileyo.
Enye yee-antibiotics ezinganyangekiyo ezivela kwiqela le-tetracycline yi-doxycycline (DC)4,5. Kuye kwaxelwa ukuba iintsalela ze-DC ezikumanzi angaphantsi komhlaba nakumanzi angaphezulu azinakwenziwa ukuba zitshintshwe, yi-20-50% kuphela ezitshintshwe kwaye ezinye zikhutshwa kwindalo esingqongileyo, nto leyo ebangela iingxaki ezinkulu kwindalo esingqongileyo nakwimpilo6.
Ukuvezwa kwi-DC kumanqanaba aphantsi kunokubulala iintsholongwane zasemanzini ezivelisa i-photosynthesis, kusongele ukusasazeka kweebhaktheriya ezilwa neentsholongwane, kwaye konyuse ukumelana neentsholongwane, ngoko ke olu ngcoliseko kufuneka lususwe emanzini amdaka. Ukonakala kwendalo kwe-DC emanzini yinkqubo ecothayo kakhulu. Iinkqubo ze-physico-chemical ezifana ne-photolysis, i-biodegradation kunye ne-adsorption zinokonakala kuphela xa ziphantsi kwaye zingamaqondo aphantsi kakhulu7,8. Nangona kunjalo, eyona ndlela ingabizi kakhulu, ilula, inobuhlobo nokusingqongileyo, kulula ukuyiphatha kwaye isebenza kakuhle yi-adsorption9,10.
I-Nano zero valent iron (nZVI) yinto enamandla kakhulu enokususa ii-antibiotics ezininzi emanzini, kuquka i-metronidazole, i-diazepam, i-ciprofloxacin, i-chloramphenicol, kunye ne-tetracycline. Olu buchule lubangelwa ziimpawu ezimangalisayo ezinazo i-nZVI, ezifana nokusebenza okuphezulu, indawo enkulu yomphezulu, kunye neendawo ezininzi zokubopha zangaphandle11. Nangona kunjalo, i-nZVI ithanda ukuhlangana kwiindawo ezinamanzi ngenxa yamandla e-van der Wells kunye neepropati eziphezulu zemagnethi, ezinciphisa ukusebenza kwayo ekususeni izinto ezingcolisayo ngenxa yokwenziwa kweengqimba ze-oxide ezithintela ukusebenza kwe-nZVI10,12. Ukuhlanganiswa kwee-particles ze-nZVI kunokuncitshiswa ngokuguqula iindawo zazo ngee-surfactants kunye nee-polymers okanye ngokuzidibanisa nezinye izinto ze-nanomaterials ngendlela yee-composites, eziye zabonakala ziyindlela efanelekileyo yokuphucula uzinzo lwazo kwindawo engqongileyo13,14.
I-Graphene yi-nanomaterial yekhabhoni enamacala amabini equlathe ii-athomu zekhabhoni ezixutyiweyo ze-sp2 ezicwangciswe kwi-lattice ye-honeycomb. Inendawo enkulu yomphezulu, amandla amakhulu oomatshini, umsebenzi ogqwesileyo we-electrocatalytic, ukuqhuba okuphezulu kobushushu, ukuhamba ngokukhawuleza kwe-electron, kunye nezinto ezifanelekileyo zokuthwala ukuxhasa ii-nanoparticles ezingaphiliyo kumphezulu wayo. Ukudibana kwee-nanoparticles zesinyithi kunye ne-graphene kunokugqitha kakhulu iingenelo zomntu ngamnye zento nganye kwaye, ngenxa yeempawu zayo eziphezulu zomzimba nezekhemikhali, kubonelela ngokusasazwa okufanelekileyo kwee-nanoparticles ukuze kulungiswe amanzi ngokufanelekileyo15.
Izicatshulwa zezityalo zezona ndlela zilungileyo zokunciphisa iikhemikhali ezinobungozi ezisetyenziswa kakhulu ekuhlanganiseni i-graphene oxide enciphisiweyo (rGO) kunye ne-nZVI kuba ziyafumaneka, azibizi kakhulu, zisebenza ngenyathelo elinye, zikhuselekile kokusingqongileyo, kwaye zingasetyenziswa njengee-reducing agents. njengee-flavonoids kunye nee-phenolic compounds nazo zisebenza njengesiqinisi. Ke ngoko, i-Atriplex halimus L. leaf extract isetyenziswe njenge-arhente yokulungisa nokuvala ukuhlanganiswa kwee-rGO/nZVI composites kolu phononongo. I-Atriplex halimus yosapho i-Amaranthaceae sisihlahla esihlala ixesha elide esithanda i-nitrogen esinoluhlu olubanzi lweendawo16.
Ngokweencwadi ezikhoyo, i-Atriplex halimus (A. halimus) yaqala ukusetyenziswa ukwenza ii-composites ze-rGO/nZVI njengendlela yokwenza izinto enoqoqosho neyokusingqongileyo. Ngoko ke, injongo yalo msebenzi inamacandelo amane: (1) i-phytosynthesis ye-rGO/nZVI kunye nee-composites zabazali be-nZVI kusetyenziswa i-A. halimus aquatic leaf extract, (2) ukuchaza ii-composites ezenziwe nge-phytosynthesized kusetyenziswa iindlela ezininzi ukuqinisekisa ukwenziwa kwazo ngempumelelo, (3) ukufunda isiphumo sokusebenzisana kwe-rGO kunye ne-nZVI ekufakweni nasekususweni kwezinto eziphilayo ezingcolisa i-doxycycline antibiotics phantsi kweeparamitha ezahlukeneyo zokusabela, ukuphucula iimeko zenkqubo yokufunxa, (3) ukuphanda izinto ezidityanisiweyo kunyango oluqhubekayo emva komjikelo wokucubungula.
I-Doxycycline hydrochloride (DC, MM = 480.90, ifomula yekhemikhali C22H24N2O·HCl, 98%), i-iron chloride hexahydrate (FeCl3.6H2O, 97%), umgubo wegrafiti othengwe kwiSigma-Aldrich, e-USA. I-Sodium hydroxide (NaOH, 97%), i-ethanol (C2H5OH, 99.9%) kunye ne-hydrochloric acid (HCl, 37%) zithengwe eMerck, e-USA. I-NaCl, i-KCl, i-CaCl2, i-MnCl2 kunye ne-MgCl2 zithengwe kwiTianjin Comio Chemical Reagent Co., Ltd. Zonke ii-reagents zicocekile kakhulu. Amanzi axutyiweyo kabini asetyenzisiwe ukulungiselela zonke izisombululo zamanzi.
Iisampulu ezimele i-A. halimus ziqokelelwe kwindawo yazo yendalo kwiNayile Delta nakwiindawo ezikunxweme lweMeditera eYiputa. Izinto zezityalo ziqokelelwe ngokwemigaqo efanelekileyo yesizwe neyehlabathi17. UNjingalwazi uManal Fawzi uchonge iisampulu zezityalo ngokwe-Boulos18, kwaye iSebe leSayensi yeNdalo kwiYunivesithi yase-Alexandria ligunyazisa ukuqokelelwa kweentlobo zezityalo ezifundwayo ngeenjongo zesayensi. Iisampulu zeesampulu zigcinwe kwiTanta University Herbarium (TANE), iisampulu zeesampulu nos. 14 122–14 127, i-herbarium kawonkewonke enika ukufikelela kwizinto ezigciniweyo. Ukongeza, ukususa uthuli okanye ukungcola, sika amagqabi esityalo abe ziingceba ezincinci, uhlambe amaxesha ama-3 ngempompo namanzi acociweyo, uze womise kwi-50°C. Isityalo sityunyuziwe, i-5 g yomgubo ocolekileyo yantywiliselwa kwi-100 ml yamanzi acociweyo yaza yaxutywa kwi-70°C imizuzu engama-20 ukuze kufunyanwe i-extract. Isicatshulwa esifunyenweyo seBacillus nicotianae sihluziwe ngephepha lesihluzo seWhatman saza sagcinwa kwiityhubhu ezicocekileyo nezicociweyo kwi-4°C ukuze sisetyenziswe ngakumbi.
Njengoko kubonisiwe kuMfanekiso 1, i-GO yenziwe ngomgubo wegrafiti ngendlela yeHummers eguquliweyo. I-10 mg yomgubo we-GO yasasazwa kwi-50 ml yamanzi acocekileyo imizuzu engama-30 phantsi kwe-sonication, kwaye emva koko i-0.9 g ye-FeCl3 kunye ne-2.9 g ye-NaAc zaxutywa imizuzu engama-60. I-20 ml ye-atriplex leaf extract yongezwa kwisisombululo esixutyiweyo ngokuxutywa kwaye yashiywa kwi-80°C iiyure ezi-8. I-black suspension ephumeyo yahluzwa. Ii-nanocomposites ezilungisiweyo zahlanjwa nge-ethanol kunye namanzi axutyiweyo zaza zomiswa kwi-oven ye-vacuum kwi-50°C iiyure ezili-12.
Iifoto ze-schematic nezedijithali zokwenziwa okuluhlaza kwe-rGO/nZVI kunye ne-nZVI complexes kunye nokususwa kwee-antibiotics ze-DC emanzini angcolileyo kusetyenziswa i-Atriplex halimus extract.
Ngokufutshane, njengoko kubonisiwe kuMfanekiso 1, i-10 ml yesisombululo se-iron chloride equlethe i-0.05 M Fe3+ ions yongezwe ngethontsi kwi-20 ml yesisombululo se-bitter leaf extract imizuzu engama-60 ngokufudumeza nokuxukuxa okuphakathi, emva koko isisombululo safakwa kwi-centrifuge kwi-14,000 rpm (Hermle, 15,000 rpm) imizuzu eli-15 ukuze kunikelwe amasuntswana amnyama, emva koko ahlanjwe kathathu nge-ethanol kunye namanzi acociweyo aze omiswe kwi-oven ye-vacuum kwi-60° C. ubusuku bonke.
Ii-composites ze-rGO/nZVI kunye ne-nZVI ezenziwe ngezityalo zibonakaliswe yi-UV-visible spectroscopy (ii-spectrophotometer ze-T70/T80 series UV/Vis, PG Instruments Ltd, UK) kuluhlu lokuskena lwe-200-800 nm. Ukuhlalutya i-topography kunye nokusasazwa kobungakanani bee-composites ze-rGO/nZVI kunye ne-nZVI, kusetyenziswe i-TEM spectroscopy (JOEL, JEM-2100F, eJapan, i-voltage ekhawulezayo ye-200 kV). Ukuvavanya amaqela asebenzayo anokubandakanyeka kwi-extracts zezityalo ezinoxanduva lwenkqubo yokubuyisela kunye nokuzinzisa, kwenziwe i-FT-IR spectroscopy (i-JASCO spectrometer kuluhlu lwe-4000-600 cm-1). Ukongeza, i-zeta potential analyzer (iZetasizer Nano ZS Malvern) isetyenzisiwe ukufunda i-surface charge ye-synthesizers nanomaterials. Kwimilinganiselo ye-X-ray diffraction yezinto ezisetyenziswa ngomgubo, kusetyenziswe i-X-ray diffractometer (X'PERT PRO, eNetherlands), esebenza kumbane (40 mA), i-voltage (45 kV) kuluhlu lwe-2θ ukusuka kwi-20° ukuya kwi-80° kunye ne-CuKa1 radiation (\(\lambda =\ ) 1.54056 Ao). I-energy dispersive X-ray spectrometer (EDX) (imodeli ye-JEOL JSM-IT100) yayinoxanduva lokufunda ukwakheka kwezinto ezisisiseko xa iqokelela i-Al K-α monochromatic X-rays ukusuka kwi--10 ukuya kwi-1350 eV kwi-XPS, ubungakanani bebala yi-400 μm K-ALPHA (Thermo Fisher Scientific, e-USA) amandla okudlulisela i-spectrum epheleleyo yi-200 eV kwaye i-spectrum encinci yi-50 eV. Isampuli yomgubo icinezelwe kwisibambi sesampuli, esibekwa kwigumbi lokucoca. I-spectrum ye-C1 s isetyenzisiwe njengesalathiso kwi-284.58 eV ukumisela amandla okubopha.
Kwenziwe uvavanyo lokufunxa ukuze kuvavanywe ukusebenza kakuhle kwee-nanocomposites ze-rGO/nZVI ezidityanisiweyo ekususeni i-doxycycline (DC) kwizisombululo zamanzi. Uvavanyo lokufunxa lwenziwe kwiiflaski ze-Erlenmeyer ezingama-25 ml ngesantya sokushukuma se-200 rpm kwi-orbital shaker (Stuart, Orbital Shaker/SSL1) kwi-298 K. Ngokuxuba isisombululo se-DC stock (1000 ppm) ngamanzi axutyiweyo. Ukuvavanya isiphumo sedosi ye-rGO/nSVI ekusebenzeni kakuhle kwe-adsorption, ii-nanocomposites ezinobunzima obahlukeneyo (0.01–0.07 g) zongezwa kwi-20 ml yesisombululo se-DC. Ukuze kufundwe i-kinetics kunye ne-adsorption isotherms, i-0.05 g ye-adsorbent yantywiliselwa kwisisombululo samanzi se-CD kunye noxinzelelo lokuqala (25–100 mg L–1). Isiphumo se-pH ekususweni kwe-DC sifundwe kwi-pH (3–11) kunye noxinzelelo lokuqala lwe-50 mg L-1 kwi-25°C. Lungisa i-pH yenkqubo ngokongeza inani elincinci lesisombululo se-HCl okanye se-NaOH (imitha ye-pH yeCrison, imitha ye-pH, i-pH 25). Ukongeza, impembelelo yobushushu bokusabela kwizilingo zokufunxa kuluhlu lwe-25-55°C iphandwe. Isiphumo samandla e-ionic kwinkqubo yokufunxa sifundwe ngokongeza uxinano olwahlukeneyo lwe-NaCl (0.01–4 mol L–1) kuxinano lokuqala lwe-DC lwe-50 mg L–1, pH 3 kunye ne-7), 25°C, kunye nedosi yokufunxa ye-0.05 g. Ukufunxwa kwe-DC engafunxwayo kulinganiswe kusetyenziswa i-dual beam UV-Vis spectrophotometer (T70/T80 series, PG Instruments Ltd, UK) exhotyiswe ngee-quartz cuvettes ze-1.0 cm ubude bendlela kubude obuphezulu be-wavelengths (λmax) be-270 kunye ne-350 nm. Ukususwa kwepesenti yee-antibiotics ze-DC (R%; Eq. 1) kunye nobungakanani be-adsorption be-DC, qt, Eq. 2 (mg/g) kulinganiswe kusetyenziswa le equation ilandelayo.
apho i-%R ilumthamo wokususa i-DC (%), i-Co luxinzelelo lokuqala lwe-DC ngexesha elingu-0, kwaye i-C luxinzelelo lwe-DC ngexesha elingu-t, ngokulandelelana (mg L-1).
apho i-qe sisixa se-DC efakwe kwi-unit mass ye-adsorbent (mg g-1), i-Co kunye ne-Ce ziingxinano ngexesha le-zero nakwi-equilibrium, ngokulandelanayo (mg l-1), i-V yi-solution volume (l), kwaye i-m yi-adsorption mass reagent (g).
Imifanekiso ye-SEM (IiFig. 2A–C) ibonisa imo ye-lamellar ye-rGO/nZVI composite ene-spherical iron nanoparticles esasazeke ngokulinganayo phezu komphezulu wayo, nto leyo ebonisa ukunamathela ngempumelelo kwe-nZVI NPs kumphezulu we-rGO. Ukongeza, kukho imibimbi ethile kwigqabi le-rGO, eqinisekisa ukususwa kwamaqela aqulethe ioksijini ngaxeshanye nokubuyiselwa kwe-A. halimus GO. Le mibimbi mikhulu isebenza njengeendawo zokulayisha i-iron NPs esebenzayo. Imifanekiso ye-nZVI (Umzobo 2D-F) ibonise ukuba ii-iron NPs ezijikelezayo zazisasazeke kakhulu kwaye azizange zihlangane, nto leyo ebangelwa yindlela yokugquma kwezixhobo zezityalo zesityalo. Ubungakanani bezinto ezikwi-particle bahluka ngaphakathi kwe-15–26 nm. Nangona kunjalo, ezinye iindawo zinemo ye-mesoporous enesakhiwo se-bulges kunye ne-cavities, enokubonelela ngamandla aphezulu okufunxa i-nZVI, kuba inokunyusa amathuba okubamba iimolekyuli ze-DC kumphezulu we-nZVI. Xa i-Rosa Damascus extract yasetyenziswa ekwenzeni i-nZVI, ii-NP ezifunyenweyo zazingafani, zine-voids kunye neemilo ezahlukeneyo, nto leyo eyanciphisa ukusebenza kwazo kwi-Cr(VI) adsorption kwaye yandisa ixesha lokuphendula 23. Iziphumo zihambelana ne-nZVI eyenziwe ngamagqabi e-oki kunye ne-mulberry, ikakhulu angama-nanoparticles angqukuva anee-nanometer ezahlukeneyo ngobukhulu ngaphandle kokudibana okucacileyo.
Imifanekiso ye-SEM yee-composites ze-rGO/nZVI (AC), i-nZVI (D, E) kunye neepateni ze-EDX zee-composites ze-nZVI/rGO (G) kunye ne-nZVI (H).
Ukwakheka kwezinto ezisisiseko ze-rGO/nZVI kunye nee-nZVI ezidityaniswe nezityalo kufundwe kusetyenziswa i-EDX (Umzobo 2G, H). Izifundo zibonisa ukuba i-nZVI yenziwe yikhabhoni (38.29% ngobunzima), ioksijini (47.41% ngobunzima) kunye nesinyithi (11.84% ngobunzima), kodwa nezinye izinto ezifana ne-phosphorus24 zikhona, ezinokufunyanwa kwizicatshulwa zezityalo. Ukongeza, ipesenti ephezulu yekhabhoni kunye neoksijini ibangelwa bubukho beekhemikhali ze-phytochemicals ezivela kwizicatshulwa zezityalo kwiisampuli ze-nZVI ezingaphantsi komhlaba. Ezi zinto zisasazwa ngokulinganayo kwi-rGO kodwa kwiimilinganiselo ezahlukeneyo: C (39.16 wt %), O (46.98 wt %) kunye neFe (10.99 wt %), i-EDX rGO/nZVI ikwabonisa ukuba kukho ezinye izinto ezifana ne-S, ezinokunxulunyaniswa nezicatshulwa zezityalo, ezisetyenziswayo. Umlinganiselo wangoku we-C:O kunye nomxholo wesinyithi kwi-rGO/nZVI composite usebenzisa i-A. halimus ungcono kakhulu kunokusebenzisa i-extract yamagqabi e-eucalyptus, njengoko ichaza ukwakheka kwe-C (23.44 wt.%), i-O (68.29 wt.% ) kunye ne-Fe (8.27 wt.%). wt %) 25. UNataša et al., 2022 baxele ukwakheka okufanayo kwe-nZVI okwenziwe ngamagqabi e-oki kunye ne-mulberry kwaye baqinisekisa ukuba amaqela e-polyphenol kunye nezinye iimolekyuli eziqulethwe kwi-extract yamagqabi zinoxanduva lwenkqubo yokunciphisa.
Imo ye-nZVI eyenziwe kwizityalo (Umzobo S2A, B) yayingqukuva kwaye ingaqhelekanga, inobukhulu obuphakathi be-particle obuyi-23.09 ± 3.54 nm, nangona kunjalo ii-chain aggregates zabonwa ngenxa yamandla e-van der Waals kunye ne-ferromagnetism. Le milo ye-particle engqukuva nengqukuva ihambelana kakuhle neziphumo ze-SEM. Uphononongo olufanayo lufunyenwe ngu-Abdelfatah et al. ngo-2021 xa i-castor bean leaf extract yasetyenziswa ekwenzeni i-nZVI11. I-Ruelas tuberosa leaf extract NPs esetyenziswa njenge-reducing agent kwi-nZVI ikwanayo nemilo ye-spherical enobubanzi obuyi-20 ukuya kwi-40 nm26.
Imifanekiso ye-hybrid rGO/nZVI composite TEM (Umzobo S2C-D) ibonise ukuba i-rGO yiplani esezantsi enemiphetho emacaleni kunye nemibimbi enika iindawo ezininzi zokulayisha ze-nZVI NPs; le morphology ye-lamellar ikwaqinisekisa ukwenziwa ngempumelelo kwe-rGO. Ukongeza, ii-nZVI NPs zinesimo esingqukuva esinobukhulu bee-particle ukusuka kwi-5.32 ukuya kwi-27 nm kwaye zifakwe kumaleko we-rGO kunye nokusasazeka okufana kakhulu. I-Eucalyptus leaf extract yasetyenziswa ukwenza i-Fe NPs/rGO; Iziphumo ze-TEM zikwaqinisekisile ukuba imibimbi kumaleko we-rGO iphucule ukusasazeka kwe-Fe NPs ngaphezu kwe-Fe NPs ecocekileyo kwaye yonyusa ukusebenza kwee-composites. Iziphumo ezifanayo zifunyenwe nguBagheri et al. 28 xa i-composite yenziwa kusetyenziswa iindlela ze-ultrasonic ezinobukhulu obuphakathi be-iron nanoparticle obumalunga ne-17.70 nm.
Iispectra ze-FTIR ze-A. halimus, nZVI, GO, rGO, kunye ne-rGO/nZVI composites ziboniswe kwiMifanekiso 3A. Ubukho bamaqela asebenzayo kumphezulu kumagqabi e-A. halimus bubonakala kwi-3336 cm-1, ehambelana neepolyphenols, kunye ne-1244 cm-1, ehambelana namaqela e-carbonyl aveliswa yiproteni. Amanye amaqela afana nee-alkanes kwi-2918 cm-1, ii-alkenes kwi-1647 cm-1 kunye nolwandiso lwe-CO-O-CO kwi-1030 cm-1 nawo abonwe, nto leyo ebonisa ukuba kukho izinto zezityalo ezisebenza njengee-sealing agents kwaye zinoxanduva lokubuyisela ukusuka kwi-Fe2+ ukuya kwi-Fe0 kunye ne-GO ukuya kwi-rGO29. Ngokubanzi, ii-nZVI spectra zibonisa iincopho ezifanayo zokufunxa njengeeswekile ezikrakra, kodwa zinotshintsho oluncinci. Ibhendi enamandla ivela kwi-3244 cm-1 enxulunyaniswa nokungcangcazela kwe-OH (ii-phenols), incopho kwi-1615 ihambelana ne-C=C, kwaye iibhendi kwi-1546 kunye ne-1011 cm-1 zivela ngenxa yokunwebeka kwe-C=O (ii-polyphenols kunye nee-flavonoids), amaqela e-CN e-aromatic amines kunye nee-aliphatic amines nawo abonwe kwi-1310 cm-1 kunye ne-1190 cm-1, ngokulandelelana13. I-FTIR spectrum ye-GO ibonisa ubukho bamaqela amaninzi aqulethe i-oxygen enamandla aphezulu, kuquka ibhendi yokunwebeka ye-alkoxy (CO) kwi-1041 cm-1, ibhendi yokunwebeka ye-epoxy (CO) kwi-1291 cm-1, i-C=O yokunwebeka. ibhendi yeentshukumo zokunwebeka ze-C=C kwi-1619 cm-1, ibhendi kwi-1708 cm-1 kunye nebhendi ebanzi yeentshukumo zokunwebeka zeqela le-OH kwi-3384 cm-1 yavela, nto leyo eqinisekiswa yindlela ephuculweyo ye-Hummers, ephumelela ekuxovuleni inkqubo yegrafiti. Xa kuthelekiswa ii-composites ze-rGO kunye ne-rGO/nZVI kunye ne-GO spectra, amandla amanye amaqela aqulethe ioksijini, afana ne-OH kwi-3270 cm-1, ancitshiswa kakhulu, ngelixa amanye, afana ne-C=O kwi-1729 cm-1, ancitshiswa ngokupheleleyo. anyamalala, nto leyo ebonisa ukususwa ngempumelelo kwamaqela asebenzayo aqulethe ioksijini kwi-GO yi-A. halimus extract. Iincopho ezintsha ezibukhali ze-rGO kwi-C=C tension zibonwa malunga ne-1560 kunye ne-1405 cm-1, eqinisekisa ukwehla kwe-GO ukuya kwi-rGO. Utshintsho oluvela kwi-1043 ukuya kwi-1015 cm-1 kunye ne-982 ukuya kwi-918 cm-1 lubonwe, mhlawumbi ngenxa yokufakwa kwezinto zezityalo31,32. UWeng et al., 2018 nabo babone ukuncitshiswa okukhulu kwamaqela asebenzayo aneoksijini kwi-GO, okuqinisekisa ukwakheka okuphumelelayo kwe-rGO ngokunciphisa i-bioreduction, kuba izicatshulwa zamagqabi e-eucalyptus, ezazisetyenziselwa ukwenza i-iron graphene oxide composites enciphisiweyo, zibonise ii-spectra ze-FTIR ezisondeleyo zamaqela asebenzayo ezityalo.33.
A. I-FTIR spectrum ye-gallium, i-nZVI, i-rGO, i-GO, i-composite rGO/nZVI (A). Ii-roentgenogrammy composites rGO, GO, nZVI kunye ne-rGO/nZVI (B).
Ukwakheka kwee-rGO/nZVI kunye nee-nZVI composites kuqinisekiswe kakhulu ziipateni ze-X-ray diffraction (Umzobo 3B). Incopho ye-Fe0 enamandla aphezulu ibonwe kwi-2Ɵ 44.5°, ehambelana ne-index (110) (JCPDS no. 06–0696)11. Enye incopho kwi-35.1° yeplane (311) ibangelwa yi-magnetite Fe3O4, i-63.2° inokunxulunyaniswa ne-index ye-Miller yeplane (440) ngenxa yokubakho kwe-ϒ-FeOOH (JCPDS no. 17-0536)34. Ipatheni ye-X-ray ye-GO ibonisa incopho ebukhali kwi-2Ɵ 10.3° kunye nencopho enye kwi-21.1°, ebonisa ukukhutshwa ngokupheleleyo kwe-graphite kwaye igxininisa ubukho bamaqela aqulethe i-oxygen kumphezulu we-GO35. Iipateni ezidityanisiweyo ze-rGO kunye ne-rGO/nZVI zirekhode ukunyamalala kweencopho ze-GO eziphawulekayo kunye nokwenziwa kweencopho ezibanzi ze-rGO kwi-2Ɵ 22.17 kunye ne-24.7° kwi-composites ze-rGO kunye ne-rGO/nZVI, ngokwahlukeneyo, nto leyo eqinisekisile ukubuyiselwa ngempumelelo kwe-GO yizicatshulwa zezityalo. Nangona kunjalo, kwipateni ye-rGO/nZVI edityanisiweyo, iincopho ezongezelelweyo ezinxulumene neplani ye-lattice ye-Fe0 (110) kunye ne-bcc Fe0 (200) zibonwe kwi-44.9\(^\circ\) kunye ne-65.22\(^\circ\), ngokwahlukeneyo .
I-zeta potential yi-potential ephakathi komaleko we-ionic onamathele kumphezulu wesuntswana kunye nesisombululo samanzi esimisela iipropati ze-electrostatic zezinto kwaye silinganise uzinzo lwaso37. Uhlalutyo lwe-Zeta potential lwee-nZVI, GO, kunye ne-rGO/nZVI ezidityaniswe nezityalo lubonise uzinzo lwazo ngenxa yokubakho kwee-negative charges ze--20.8, -22, kunye ne--27.4 mV, ngokulandelelana, kumphezulu wazo, njengoko kubonisiwe kuMfanekiso S1A-C. . Ezi ziphumo zihambelana neengxelo ezininzi ezikhankanya ukuba izisombululo eziqulethe ii-particles ezine-zeta potential values ezingaphantsi kwe--25 mV ngokubanzi zibonisa izinga eliphezulu lokuzinza ngenxa ye-electrostatic repulsion phakathi kwezi suntswana. Ukudibana kwe-rGO kunye ne-nZVI kuvumela i-composite ukuba ifumane ii-negative charges ezingaphezulu kwaye ngaloo ndlela inozinzo oluphezulu kune-GO okanye i-nZVI yodwa. Ke ngoko, i-mento ye-electrostatic repulsion iya kukhokelela ekwakhiweni kwee-stable rGO/nZVI39 composites. Umphezulu ongalunganga we-GO uvumela ukuba isasazeke ngokulinganayo kwindawo enamanzi ngaphandle kokudibana, nto leyo edala iimeko ezifanelekileyo zokunxibelelana ne-nZVI. Itshaja engalunganga inokunxulunyaniswa nokubakho kwamaqela ahlukeneyo asebenzayo kwi-bitter melon extract, nto leyo eqinisekisa ukusebenzisana phakathi kwe-GO kunye ne-iron precursors kunye ne-plant extract ukwenza i-rGO kunye ne-nZVI, ngokwahlukeneyo, kunye ne-rGO/nZVI complex. Ezi khompawundi zezityalo zinokusebenza njengee-capping agents, njengoko zithintela ukuhlanganiswa kwee-nanoparticles eziphumayo kwaye ngaloo ndlela zonyusa uzinzo lwazo40.
Ulwakhiwo lwezinto ezisisiseko kunye neemeko ze-valence ze-nZVI kunye ne-rGO/nZVI composites zichongiwe yi-XPS (Umzobo 4). Uphononongo lwe-XPS lubonise ukuba i-composite ye-rGO/nZVI yenziwe ikakhulu zizinto ze-C, O, kunye ne-Fe, ezihambelana nemephu ye-EDS (Umzobo 4F–H). I-spectrum ye-C1s ineencopho ezintathu kwi-284.59 eV, 286.21 eV kunye ne-288.21 eV ezimele i-CC, i-CO kunye ne-C=O, ngokwahlukeneyo. I-spectrum ye-O1s yahlulwe yaba ziincopho ezintathu, kuquka i-531.17 eV, i-532.97 eV, kunye ne-535.45 eV, ezabelwe amaqela e-O=CO, i-CO, kunye ne-NO, ngokwahlukeneyo. Nangona kunjalo, iincopho kwi-710.43, 714.57 kunye ne-724.79 eV zibhekisa kwi-Fe 2p3/2, i-Fe+3 kunye ne-Fe p1/2, ngokwahlukeneyo. Iispectra ze-XPS ze-nZVI (Umzobo 4C-E) zibonise iincopho zezinto ezi-C, O, kunye neFe. Iincopho kwi-284.77, 286.25, kunye ne-287.62 eV ziqinisekisa ubukho bee-alloys ze-iron-carbon, njengoko zibhekisa kwi-CC, C-OH, kunye ne-CO, ngokwahlukeneyo. I-spectrum ye-O1s ihambelana neencopho ezintathu ze-C–O/iron carbonate (531.19 eV), i-hydroxyl radical (532.4 eV) kunye ne-O–C=O (533.47 eV). Incopho kwi-719.6 ibangelwa yi-Fe0, ngelixa i-FeOOH ibonisa iincopho kwi-717.3 kunye ne-723.7 eV, ukongeza, incopho kwi-725.8 eV ibonisa ubukho be-Fe2O342.43.
Izifundo ze-XPS ze-nZVI kunye ne-rGO/nZVI composites, ngokulandelelana (A, B). I-spectra epheleleyo ye-nZVI C1s (C), Fe2p (D), kunye ne-O1s (E) kunye ne-rGO/nZVI C1s (F), Fe2p (G), O1s (H) composite.
I-N2 adsorption/desorption isotherm (Umzobo 5A, B) ibonisa ukuba i-nZVI kunye ne-rGO/nZVI composites zezohlobo II. Ukongeza, indawo ethile yomphezulu (SBET) ye-nZVI inyuke ukusuka kwi-47.4549 ukuya kwi-152.52 m2/g emva kokufiphaza nge-rGO. Esi siphumo sinokuchazwa kukwehla kweempawu zemagnethi ze-nZVI emva kokufiphaza nge-rGO, ngaloo ndlela kunciphisa ukuhlanganiswa kwamasuntswana kunye nokwandisa indawo yomphezulu we-composites. Ukongeza, njengoko kubonisiwe kwi-Fig. 5C, umthamo we-pore (8.94 nm) we-rGO/nZVI composite uphezulu kunowe-nZVI yokuqala (2.873 nm). Esi siphumo siyavumelana no-El-Monaem et al. 45.
Ukuvavanya amandla okufunxa ukususa i-DC phakathi kwee-composites ze-rGO/nZVI kunye ne-nZVI yokuqala kuxhomekeke ekwandeni koxinzelelo lokuqala, kwenziwe uthelekiso ngokongeza idosi engaguqukiyo ye-adsorbent nganye (0.05 g) kwi-DC kumanqanaba ahlukeneyo okuqala. Isisombululo esiphandiweyo [25]. –100 mg l–1] kwi-25°C. Iziphumo zibonise ukuba ukusebenza kakuhle kokususa (94.6%) kwe-composite ye-rGO/nZVI kwakuphezulu kunokwe-nZVI yokuqala (90%) kuxinzelelo oluphantsi (25 mg L-1). Nangona kunjalo, xa uxinzelelo lokuqala lwandiswa ukuya kwi-100 mg L-1, ukusebenza kakuhle kokususa i-rGO/nZVI kunye ne-nZVI yomzali kwehle ukuya kwi-70% kunye ne-65%, ngokulandelanayo (Umfanekiso 6A), okunokubangelwa ziindawo ezimbalwa ezisebenzayo kunye nokuwohloka kwamasuntswana e-nZVI. Ngokuchasene noko, i-rGO/nZVI ibonise ukusebenza okuphezulu kokususwa kwe-DC, okunokubangelwa yimpembelelo yokusebenzisana phakathi kwe-rGO kunye ne-nZVI, apho iindawo ezisebenzayo ezizinzileyo ezikhoyo zokufunxa ziphezulu kakhulu, kwaye kwimeko ye-rGO/nZVI, i-DC engaphezulu inokufunxa kune-nZVI engaguqukiyo. Ukongeza, kumzobo 6B ubonisa ukuba amandla okufunxa e-rGO/nZVI kunye nee-nZVI composites anyuke ukusuka kwi-9.4 mg/g ukuya kwi-30 mg/g kunye ne-9 mg/g, ngokulandelelana, kunye nokwanda koxinzelelo lokuqala ukusuka kwi-25–100 mg/L. -1.1 ukuya kwi-28.73 mg g-1. Ke ngoko, izinga lokususwa kwe-DC lalinxulumene kakubi noxinzelelo lokuqala lwe-DC, olwalubangelwa linani elincinci lamaziko okusabela axhaswa yi-adsorbent nganye yokufunxa kunye nokususa i-DC kwisisombululo. Ngoko ke, kunokufikelelwa kwisigqibo sokuba ii-composites ze-rGO/nZVI zisebenza kakuhle kakhulu ekufakweni nasekuncitshisweni, kwaye i-rGO ekubunjweni kwe-rGO/nZVI ingasetyenziswa zombini njenge-adsorbent kunye nesixhobo sokuthwala.
Ukusebenza kakuhle kokususa kunye nomthamo wokufunxa we-DC kwi-rGO/nZVI kunye ne-nZVI composite yayizi (A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, umthamo = 0.05 g], pH. kumthamo wokufunxa kunye nokusebenza kakuhle kokususa kwe-DC kwi-rGO/nZVI composites (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, umthamo = 0.05 g].
I-pH yesisombululo yinto ebalulekileyo kuphononongo lweenkqubo zokufunxa, kuba ichaphazela inqanaba le-ionization, i-speciation, kunye ne-ionization ye-adsorbent. Olu vavanyo lwenziwe kwi-25°C ngedosi ye-adsorbent engaguqukiyo (0.05 g) kunye noxinzelelo lokuqala lwe-50 mg L-1 kuluhlu lwe-pH (3–11). Ngokutsho kophononongo loncwadi46, i-DC yimolekyuli ye-amphiphilic enamaqela amaninzi asebenzayo e-ionizable (ii-phenols, amaqela e-amino, ii-alcohols) kumanqanaba ahlukeneyo e-pH. Ngenxa yoko, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumeneyo kumphezulu we-rGO/nZVI composite zinokusebenzisana ngombane kwaye zinokubakho njenge-cations, zwitterions, kunye nee-anions, i-DC molecule ikhona njenge-cationic (DCH3+) kwi-pH < 3.3, zwitterionic (DCH20) 3.3 < pH < 7.7 kunye ne-anionic (DCH− okanye i-DC2−) kwi-PH 7.7. Ngenxa yoko, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumeneyo kumphezulu we-rGO/nZVI composite zinokusebenzisana ngombane kwaye zinokubakho njenge-cations, zwitterions, kunye nee-anions, i-DC molecule ikhona njenge-cationic (DCH3+) kwi-pH < 3.3, zwitterionic (DCH20) 3.3 < pH < 7.7 kunye ne-anionic (DCH- okanye i-DC2-) kwi-PH 7.7. В результате различные функции ДК и связанных с ними структур на поверхности композита rGO/nZVI могут в заимодействовать электровста виде катионов, цвиттер-ионов и анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер-ионный (DCH20) <7 DCH20 pH 3, 3,3 okanye DC2-) nge pH 7,7. Ngenxa yoko, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumene noko kumphezulu we-rGO/nZVI composite zinokusebenzisana ngombane kwaye zinokubakho ngohlobo lwee-cations, ii-zwitterions, kunye nee-anions; i-molekyuli ye-DC ikhona njenge-cation (DCH3+) kwi-pH < 3.3; i-ionic (DCH20) 3.3 < pH < 7.7 kunye ne-anionic (DCH- okanye i-DC2-) kwi-pH 7.7.因此，DC 的各种功能和rGO/nZVI复合材料表面的相关结构可能会发生静电相互作用，并可能以阳离子、两性结构可能会发生静电相互作用，并可能以阳离子、两性离子和阴离的公牛，在公牛3时以阳离子(DCH3+) 的形式存在，两性离子(DCH20) 3.3
Isiphumo sobushushu ekufakweni kwesisombululo samanzi se-DC senziwe kwi (25–55°C). Umfanekiso 7A ubonisa isiphumo sokwanda kobushushu ekusebenzeni kakuhle kokususwa kwee-antibiotics ze-DC kwi-rGO/nZVI, kuyacaca ukuba amandla okususa kunye namandla okufunxa anyukile ukusuka kwi-83.44% kunye ne-13.9 mg/g ukuya kwi-47% kunye ne-7.83 mg/g. , ngokulandelelana. Oku kuncipha okukhulu kunokubangelwa kukwanda kwamandla obushushu ee-DC ions, okukhokelela ekukhutshweni kwe-47.
Isiphumo soBushushu kwiNdleko yoKususa kunye noKufunxa amandla eCD kwi-rGO/nZVI Composites (A) [Co = 50 mg L–1, pH = 7, Idosi = 0.05 g], Idosi yoKufunxa amandla okususa kunye noKususa Ukusebenza kakuhle kweCD Isiphumo soQokelelo lokuqala kwiNdleko yoKufunxa amandla kunye nokusebenza kakuhle kokususwa kweDC kwi-rGO/nSVI composite (B) [Co = 50 mg L–1, pH = 7, T = 25°C] (C, D) [Co = 25–100 mg L–1, pH = 7, T = 25 °C, idosi = 0.05 g].
Isiphumo sokunyusa idosi ye-composite adsorbent rGO/nZVI ukusuka kwi-0.01 g ukuya kwi-0.07 g ekusebenzeni kakuhle kokususa kunye namandla okufunxa kuboniswe kuMfanekiso . 7B. Ukwanda kwedosi ye-adsorbent kukhokelele ekwehleni kwamandla okufunxa ukusuka kwi-33.43 mg/g ukuya kwi-6.74 mg/g. Nangona kunjalo, ngokwanda kwedosi ye-adsorbent ukusuka kwi-0.01 g ukuya kwi-0.07 g, ukusebenza kakuhle kokususa kuyanda ukusuka kwi-66.8% ukuya kwi-96%, nto leyo, ngokufanelekileyo, inokunxulunyaniswa nokwanda kwenani lamaziko asebenzayo kumphezulu we-nanocomposite.
Isiphumo soxinzelelo lokuqala kumthamo wokufunxa kunye nokusebenza kakuhle kokususa [25–100 mg L-1, 25°C, pH 7, idosi 0.05 g] sifundwe. Xa uxinzelelo lokuqala lunyusiwe ukusuka kwi-25 mg L-1 ukuya kwi-100 mg L-1, ipesenti yokususwa kwe-rGO/nZVI composite yehla ukusuka kwi-94.6% ukuya kwi-65% (Umzobo 7C), mhlawumbi ngenxa yokungabikho kweendawo ezisebenzayo ezifunekayo. . Ifunxa uxinano olukhulu lwe-DC49. Kwelinye icala, njengoko uxinzelelo lokuqala lusanda, amandla okufunxa nawo anyuke ukusuka kwi-9.4 mg/g ukuya kwi-30 mg/g de kufikelelwe kumlinganiselo ofanayo (Umzobo 7D). Le mpendulo ingenakuphepheka ibangelwa kukwanda kwamandla okuqhuba kunye noxinano lokuqala lwe-DC olukhulu kunoxhathiso lokudluliselwa kobunzima be-DC ion ukufikelela kumphezulu 50 we-rGO/nZVI composite.
Ixesha lokudibana kunye nezifundo ze-kinetic zijolise ekuqondeni ixesha lokulingana lokutsalwa. Okokuqala, ubungakanani be-DC efakwe kwi-intanethi kwimizuzu yokuqala engama-40 yexesha lokudibana babumalunga nesiqingatha senani lilonke elifakwe kwi-intanethi kulo lonke ixesha (imizuzu eli-100). Ngelixa iimolekyuli ze-DC kwisisombululo zingqubana zibangela ukuba zifudukele ngokukhawuleza kumphezulu we-rGO/nZVI composite nto leyo ebangela ukutsalwa okukhulu. Emva kwemizuzu engama-40, ukutsalwa kwe-DC kwanda kancinci kancinci de kwafikelelwa kukulingana emva kwemizuzu engama-60 (Umzobo 7D). Ekubeni isixa esifanelekileyo sitsalwa kwi-intanethi kwimizuzu engama-40 yokuqala, kuya kubakho ukungqubana okuncinci neemolekyuli ze-DC kwaye kuya kubakho iindawo ezimbalwa ezisebenzayo kwiimolekyuli ezingatsalwanga. Ke ngoko, izinga lokutsalwa linokuncipha51.
Ukuze kuqondwe ngcono i-adsorption kinetics, kusetyenziswe iiploti zomgca we-pseudo first order (Umzobo 8A), i-pseudo second order (Umzobo 8B), kunye neemodeli ze-Elovich (Umzobo 8C). Kwiiparameters ezifunyenwe kwizifundo ze-kinetic (Itheyibhile S1), kuyacaca ukuba imodeli ye-pseudosecond yeyona modeli ilungileyo yokuchaza i-adsorption kinetics, apho ixabiso le-R2 libekwe phezulu kunezinye iimodeli ezimbini. Kukwakho ukufana phakathi kwamandla e-adsorption abaliweyo (qe, cal). I-pseudo-second order kunye namaxabiso ovavanyo (qe, exp.) bubungqina obongezelelekileyo bokuba i-pseudo-second order yimodeli engcono kunezinye iimodeli. Njengoko kubonisiwe kwiTheyibhile 1, amaxabiso e-α (isantya sokuqala se-adsorption) kunye ne-β (i-desorption constant) aqinisekisa ukuba isantya se-adsorption siphezulu kunesantya se-desorption, nto leyo ebonisa ukuba i-DC ithambekele eku-adsorption ngokufanelekileyo kwi-rGO/nZVI52 composite. .
Iiploti ze-kinetic ze-adsorption ezilandelelanayo ze-pseudo-second order (A), i-pseudo-first order (B) kunye ne-Elovich (C) [Co = 25–100 mg l–1, pH = 7, T = 25 °C, idosi = 0.05 g].
Izifundo ze-adsorption isotherms zinceda ekumiseleni umthamo we-adsorption we-adsorbent (i-RGO/nRVI composite) kwii-adsorbate concentrations ezahlukeneyo (DC) kunye namaqondo obushushu enkqubo. Umthamo ophezulu we-adsorption ubalwe kusetyenziswa i-Langmuir isotherm, eyabonisa ukuba i-adsorption yayifana kwaye yaquka ukwakheka kwe-adsorbate monolayer kumphezulu we-adsorbent ngaphandle kokusebenzisana phakathi kwazo53. Ezinye iimodeli ezimbini ze-isotherm ezisetyenziswa kakhulu ziimodeli zeFreundlich kunye neTemkin. Nangona imodeli yeFreundlich ingasetyenziswanga ukubala umthamo we-adsorption, inceda ukuqonda inkqubo ye-adsorption eyahlukileyo kwaye izithuba ezikwi-adsorbent zinamandla ahlukeneyo, ngelixa imodeli yeTemkin inceda ukuqonda iipropati zomzimba nezekhemikhali ze-adsorption54.
Imifanekiso 9A-C ibonisa iiploti zomgca zeemodeli zeLangmuir, Freindlich, kunye neTemkin, ngokulandelelana. Amaxabiso e-R2 abalwe kwiiploti zomgca zeFreundlich (Umzobo 9A) kunye neLangmuir (Umzobo 9B) kwaye aboniswe kwiTheyibhile 2 abonisa ukuba i-DC adsorption kwi-rGO/nZVI composite ilandela iimodeli ze-isotherm zeFreundlich (0.996) kunye neLangmuir (0.988) kunye neTemkin (0.985). Umthamo ophezulu we-adsorption (qmax), obalwa kusetyenziswa imodeli ye-isotherm yeLangmuir, yayiyi-31.61 mg g-1. Ukongeza, ixabiso elibaliweyo le-dimensionless separation factor (RL) liphakathi kwe-0 kunye ne-1 (0.097), ebonisa inkqubo ye-adsorption evumayo. Ngaphandle koko, i-Freundlich constant ebaliweyo (n = 2.756) ibonisa ukhetho lwale nkqubo yokufunxa. Ngokwemodeli ethe ngqo ye-Temkin isotherm (Umzobo 9C), ukufunxwa kwe-DC kwi-composite ye-rGO/nZVI yinkqubo yokufunxwa ngokwasemzimbeni, kuba i-b yi-˂ 82 kJ mol-1 (0.408)55. Nangona ukufunxwa ngokwasemzimbeni kudla ngokubangelwa ngamandla abuthathaka e-van der Waals, ukufunxwa kwamandla ngqo kwii-composite ze-rGO/nZVI kufuna amandla aphantsi okufunxwa [56, 57].
I-isotherms ye-Freundlich (A), Langmuir (B), kunye ne-Temkin (C) ye-linear adsorption [Co = 25–100 mg L–1, pH = 7, T = 25 °C, idosi = 0.05 g]. Iploti ye-van't Hoff equation ye-DC adsorption yi-rGO/nZVI composites (D) [Co = 25–100 mg l-1, pH = 7, T = 25–55 °C kunye nedosi = 0.05 g].
Ukuvavanya impembelelo yotshintsho lobushushu bokusabela ekususweni kwe-DC kwi-rGO/nZVI composites, iiparameter ze-thermodynamic ezifana notshintsho lwe-entropy (ΔS), utshintsho lwe-enthalpy (ΔH), kunye notshintsho lwamandla akhululekileyo (ΔG) zibalwe kwi-equation. 3 kunye ne-458.
apho \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) – i-thermodynamic equilibrium constant, i-Ce kunye ne-CAe – i-rGO kwisisombululo, ngokulandelanayo /nZVI DC concentrations kwi-surface equilibrium. I-R kunye ne-RT zii-gas constant kunye ne-adsorption temperature, ngokulandelanayo. Ukuzoba i-ln Ke ngokuchasene ne-1/T kunika umgca othe tye (Umzobo 9D) apho i-∆S kunye ne-∆H zinokumiselwa khona.
Ixabiso elibi le-ΔH libonisa ukuba le nkqubo ingaphandle kobushushu. Kwelinye icala, ixabiso le-ΔH likwinkqubo yokufunxa ngokwasemzimbeni. Amaxabiso abi le-ΔG kwiTheyibhile 3 abonisa ukuba ukufunxa kunokwenzeka kwaye kwenzeka ngokuzenzekelayo. Amaxabiso abi le-ΔS abonisa ukulandelelana okuphezulu kweemolekyuli ezifunxayo kwindawo yolwelo (Itheyibhile 3).
Itheyibhile 4 ithelekisa i-composite ye-rGO/nZVI kunye nezinye ii-adsorbents ezixelwe kwizifundo zangaphambili. Kuyacaca ukuba i-composite ye-VGO/nCVI inomthamo ophezulu wokufunxa kwaye inokuba yinto ethembisayo yokususa ii-antibiotics ze-DC emanzini. Ukongeza, ukufunxa ii-composite ze-rGO/nZVI yinkqubo ekhawulezayo enexesha lokulinganisa lemizuzu engama-60. Iipropati ezibalaseleyo zokufunxa ii-composite ze-rGO/nZVI zinokuchazwa yimpembelelo yokusebenzisana kwe-rGO kunye ne-nZVI.
Imifanekiso 10A, B ibonisa indlela enengqondo yokususa ii-antibiotics ze-DC yi-rGO/nZVI kunye ne-nZVI complexes. Ngokweziphumo zovavanyo malunga nempembelelo ye-pH ekusebenzeni kakuhle kwe-DC adsorption, kunye nokunyuka kwe-pH ukusuka kwi-3 ukuya kwi-7, i-DC adsorption kwi-rGO/nZVI composite ayizange ilawulwe yi-electrostatic interactions, kuba yayisebenza njenge-zwitterion; ngoko ke, utshintsho kwixabiso le-pH aluzange luchaphazele inkqubo ye-adsorption. Emva koko, indlela ye-adsorption inokulawulwa yi-non-electrostatic interactions efana ne-hydrogen bonding, i-hydrophobic effects, kunye ne-π-π stacking interactions phakathi kwe-rGO/nZVI composite kunye ne-DC66. Kuyaziwa ukuba indlela ye-aromatic adsorbates kwi-surfaces ye-layered graphene ichazwe yi-π–π stacking interactions njengamandla aphambili okuqhuba. I-compound yinto enamaleko afana ne-graphene enomlinganiselo ophezulu wokufunxa kwi-233 nm ngenxa yotshintsho lwe-π-π*. Ngokusekelwe ekubeni kukho izangqa ezine ze-aromatic kwisakhiwo se-molecular se-DC adsorbate, sicinge ukuba kukho indlela yokusebenzisana kwe-π-π-stacking phakathi kwe-aromatic DC (π-electron acceptor) kunye nommandla otyebileyo kwi-π-electrons kumphezulu we-RGO. /nZVI composites. Ukongeza, njengoko kubonisiwe kumzobo 10B, izifundo ze-FTIR zenziwe ukuze kufundwe ukusebenzisana kwe-molecular ye-rGO/nZVI composites kunye ne-DC, kwaye i-FTIR spectra ye-rGO/nZVI composites emva kwe-DC adsorption iboniswe kuMfanekiso 10B. 10b. Incochoyi entsha ibonwa kwi-2111 cm-1, ehambelana nokungcangcazela kwesakhelo se-C=C bond, ebonisa ukuba kukho amaqela asebenzayo e-organic ahambelanayo kumphezulu we-67 rGO/nZVI. Ezinye iincopho ziyatshintsha ukusuka kwi-1561 ukuya kwi-1548 cm-1 kwaye ukusuka kwi-1399 ukuya kwi-1360 cm-1, nto leyo eqinisekisa ukuba ukusebenzisana kwe-π-π kudlala indima ebalulekileyo ekufakweni kwe-graphene kunye nongcoliseko lwezinto eziphilayo68,69. Emva kokutsalwa kwe-DC, amandla amanye amaqela aqulethe i-oksijini, njenge-OH, ehle aya kwi-3270 cm-1, nto leyo ebonisa ukuba ukubophelela kwe-hydrogen yenye yeendlela zokutsalwa. Ngoko ke, ngokusekelwe kwiziphumo, ukutsalwa kwe-DC kwi-composite ye-rGO/nZVI kwenzeka ikakhulu ngenxa yokusebenzisana kwe-π-π stacking kunye nee-H-bonds.
Indlela eqiqileyo yokufunxa ii-antibiotics ze-DC yi-rGO/nZVI kunye nee-nZVI complexes (A). Iispectra zokufunxa ze-FTIR ze-DC kwi-rGO/nZVI kunye ne-nZVI (B).
Ubunzulu beebhendi zokufunxa ze-nZVI kwi-3244, 1615, 1546, kunye ne-1011 cm–1 banda emva kokufunxa kwe-DC kwi-nZVI (Umzobo 10B) xa kuthelekiswa ne-nZVI, ekufuneka inxulumene nokusebenzisana namaqela asebenzayo anokubakho amaqela e-carboxylic acid O kwi-DC. Nangona kunjalo, le pesenti iphantsi yokudluliselwa kuzo zonke iibhendi ezibonisiweyo ayibonisi tshintsho lubalulekileyo ekusebenzeni kakuhle kokufunxa kwe-phytosynthetic adsorbent (nZVI) xa kuthelekiswa ne-nZVI ngaphambi kwenkqubo yokufunxa. Ngokutsho kophando oluthile lokususa i-DC nge-nZVI71, xa i-nZVI isabela kwi-H2O, ii-electron ziyakhululwa kwaye emva koko i-H+ isetyenziselwa ukuvelisa i-hydrogen esebenzayo encitshiswa kakhulu. Okokugqibela, ezinye ii-cationic compounds zamkela ii-electron ezivela kwi-hydrogen esebenzayo, nto leyo ebangela ukuba i--C=N kunye ne--C=C-, nto leyo ebangelwa kukuqhekeka kweringi ye-benzene.
Ixesha lokuthumela: Novemba-14-2022