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Kulo msebenzi, imidibaniso ye-rGO/nZVI yadityaniswa okokuqala ngqa kusetyenziswa inkqubo elula kunye nokusingqongileyo usebenzisa i-Sophora yellowish leaf extract njenge-arhente yokunciphisa kunye nokuzinzisa ukuhambelana nemigaqo ye-chemistry "eluhlaza", njenge-chemical synthesis enobungozi obuncinci. Izixhobo ezininzi zisetyenziselwe ukuqinisekiswa kokuphumelela ukuhlanganiswa kwee-composites, ezifana ne-SEM, i-EDX, i-XPS, i-XRD, i-FTIR, kunye ne-zeta enokubakho, ebonisa ukuphumelela kwe-composite. Umthamo wokususwa kwenoveli edityanisiweyo kunye ne-nZVI esulungekileyo kwiindawo ezahlukeneyo zokuqala ze-antibiotic doxycycline yathelekiswa nokuphanda isiphumo se-synergistic phakathi kwe-rGO kunye ne-ZVI. Ngaphantsi kweemeko zokususa ze-25mg L-1, 25 ° C kunye ne-0.05g, izinga lokususa i-adsorptive ye-nZVI ecocekileyo yayiyi-90%, ngelixa izinga lokususa i-adsorptive ye-doxycycline yi-rGO/nZVI composite ifikelele kwi-94.6%, eqinisekisa ukuba i-NZVI kunye ne-rGO . Inkqubo ye-adsorption ihambelana nomyalelo we-pseudo-yesibini kwaye ivumelana kakuhle kunye nemodeli ye-Freundlich enomthamo omkhulu we-adsorption we-31.61 mg g-1 kwi-25 ° C kunye ne-pH 7. Indlela efanelekileyo yokususwa kwe-DC iphakanyisiwe. Ukongeza, ukuphinda kusetyenziswe i-rGO/nZVI composite yayingu-60% emva kwemijikelo emithandathu elandelelanayo yokuvuselela.
Ukunqongophala kwamanzi nongcoliseko ngoku kusisisongelo esinzulu kuwo onke amazwe. Kwiminyaka yakutshanje, ungcoliseko lwamanzi, ngakumbi ungcoliseko lokubulala iintsholongwane, lunyukile ngenxa yokwanda kwemveliso kunye nokusetyenziswa ngexesha lobhubhani we-COVID-1,2,3. Ngoko ke, ukuphuhliswa kobuchwepheshe obusebenzayo bokupheliswa kwe-antibiotics kumanzi amdaka ngumsebenzi ophuthumayo.
Enye yee-antibiotics ezichasayo ze-semi-synthetic ezivela kwiqela le-tetracycline yi-doxycycline (DC)4,5. Kuye kwaxelwa ukuba iintsalela ze-DC kumanzi aphantsi komhlaba kunye namanzi angaphezulu azikwazi ukuguqulwa kwe-metabolized, kuphela i-20-50% ye-metabolized kwaye enye ikhutshelwa kwindalo, ibangela iingxaki ezinzulu zokusingqongileyo kunye nempilo6.
Ukubonakaliswa kwe-DC kumanqanaba aphantsi kunokubulala i-aquatic photosynthetic microorganisms, isongele ukusasazeka kwebhaktheriya ye-antimicrobial, kunye nokwandisa ukuchasana kwe-antimicrobial, ngoko ke le nkunkuma kufuneka isuswe emanzini amdaka. Ukuthotywa kwendalo kwe-DC emanzini yinkqubo ecothayo kakhulu. Iinkqubo ze-Physico-chemical ezifana ne-photolysis, i-biodegradation kunye ne-adsorption inokunciphisa kuphela kwiindawo eziphantsi kunye namazinga aphantsi kakhulu7,8. Nangona kunjalo, eyona ndlela yoqoqosho, elula, ehambelana nokusingqongileyo, kulula ukuyiphatha kunye nendlela efanelekileyo yi-adsorption9,10.
I-Nano zero valent iron (nZVI) yinto enamandla kakhulu enokususa i-antibiotics ezininzi emanzini, kuquka i-metronidazole, i-diazepam, i-ciprofloxacin, i-chloramphenicol, kunye ne-tetracycline. Obu buchule bubangelwa ziipropati ezimangalisayo i-NZVI inazo, ezifana nokusebenza kwakhona okuphezulu, indawo enkulu yomphezulu, kunye neendawo ezininzi ezibophelelayo zangaphandle11. Nangona kunjalo, i-nZVI ithande ukudityaniswa kumajelo eendaba amanzi ngenxa yemikhosi ye-van der Wells kunye neempawu eziphezulu zemagneti, ezinciphisa ukusebenza kwayo ekususeni ukungcola ngenxa yokwakheka kweengqimba ze-oxide ezithintela ukusebenza kwakhona kwe-nZVI10,12. I-agglomeration ye-nZVI particles ingancitshiswa ngokuguqula indawo yazo kunye ne-surfactants kunye ne-polymers okanye ngokudibanisa namanye ama-nanomaterials ngendlela yee-composites, eziye zabonisa ukuba ziyindlela efanelekileyo yokuphucula ukuzinza kwazo kwindawo13,14.
IGraphene yikhabhoni enamacala amabini inanomaterial equka i-sp2-hybridized carbon athom ezicwangciswe kwileti yenqatha lobusi. Inommandla omkhulu ongaphezulu, amandla omatshini abalulekileyo, umsebenzi ogqwesileyo we-electrocatalytic, ukuhanjiswa kwe-thermal ephezulu, ukuhamba kwe-electron ngokukhawuleza, kunye nezinto ezifanelekileyo zokuthwala ukuxhasa i-nanoparticles ephilayo kumphezulu wayo. Ukudibanisa i-nanoparticles yensimbi kunye ne-graphene inokugqithisa kakhulu izibonelelo zomntu ngamnye kwaye, ngenxa yeempawu zayo eziphezulu zomzimba kunye neekhemikhali, zibonelela ngokusasazwa ngokufanelekileyo kwe-nanoparticles ukwenzela unyango olufanelekileyo lwamanzi15.
Izicatshulwa zezityalo zizona ndlela zingcono kwii-agent zokunciphisa iikhemikhali ezinobungozi ezisetyenziswa ngokuqhelekileyo kwi-synthesis yokunciphisa i-graphene oxide (rGO) kunye ne-nZVI kuba zikhoyo, zingabizi, zinyathelo elinye, zikhuselekile ngokusingqongileyo, kwaye zingasetyenziswa njengee-arhente zokunciphisa. njenge-flavonoids kunye neekhompawundi ze-phenolic nazo zisebenza njenge-stabilizer. Ngoko ke, i-Atriplex halimus L. i-leaf extract isetyenziswe njenge-agent yokulungisa kunye nokuvala ukuhlanganiswa kwe-rGO / nZVI composites kolu cwaningo. I-Atriplex halimus evela kusapho i-Amaranthaceae sisihlahla sonyaka esithanda initrogen enoluhlu olubanzi lwejografi16.
Ngokoncwadi olukhoyo, i-Atriplex halimus (A. halimus) yaqala ukusetyenziswa ukwenza imidibaniso ye-rGO/nZVI njengendlela yokudibanisa eyoqoqosho kunye nokusingqongileyo. Ngaloo ndlela, injongo yalo msebenzi inamacandelo amane: (1) i-phytosynthesis ye-rGO/nZVI kunye ne-nZVI composites yomzali esebenzisa i-A. halimus leaf extract, (2) ukubonakaliswa kwe-phytosynthesized composites usebenzisa iindlela ezininzi zokuqinisekisa ukuveliswa kwazo ngempumelelo, (3) ) funda impembelelo ye-synergistic ye-rGO kunye ne-nZVI kwi-adsorption kunye nokususwa kwezinto ezingcolileyo ze-doxycycline antibiotics phantsi kweeparameters zokusabela ezahlukeneyo, lungisa iimeko zenkqubo ye-adsorption, (3) phanda izinto ezidibeneyo kunyango olwahlukeneyo oluqhubekayo emva komjikelo wokucubungula.
I-Doxycycline hydrochloride (DC, MM = 480.90, i-chemical formula C22H24N2O · HCl, 98%), i-iron chloride hexahydrate (FeCl3.6H2O, 97%), i-graphite powder ethengwe kwi-Sigma-Aldrich, eU.SA. I-sodium hydroxide (NaOH, 97%), i-ethanol (C2H5OH, 99.9%) kunye ne-hydrochloric acid (HCl, 37%) yathengwa kwi-Merck, eU.SA. I-NaCl, i-KCl, i-CaCl2, i-MnCl2 kunye ne-MgCl2 yathengwa kwi-Tianjin Comio Chemical Reagent Co., Ltd. Zonke ii-reagents zicocekile ngokuhlalutya okuphezulu. Amanzi adilwe kabini asetyenziselwa ukulungisa zonke izisombululo ezinamanzi.
Iisampuli ezimele ze-A. halimus ziqokelelwe kwindawo yazo yendalo kwi-Nayile Delta kunye namazwe agudle unxweme lweMeditera e-Egypt. Izixhobo zezityalo zaqokelelwa ngokuhambelana nezikhokelo zesizwe nezamazwe ngamazwe ezisebenzayo17. UProf. Manal Fawzi uchonge imizekelo yezityalo ngokutsho kwe-Boulos18, kwaye iSebe lezeNzululwazi ngokusiNgqongileyo leYunivesithi yase-Alexandria ligunyazisa ukuqokelelwa kweentlobo zezityalo ezifundiweyo ngeenjongo zenzululwazi. Iisampulu zevawutsha zibanjelwe eTanta University Herbarium (TANE), iinombolo zevawutsha. 14 122–14 127, i-herbarium yoluntu ebonelela ngokufikelela kwizinto ezidipozithiweyo. Ukongezelela, ukususa uthuli okanye ukungcola, nqumla amaqabunga esityalo sibe ngamaqhekeza amancinci, uhlambulule amaxesha ama-3 ngompompo kunye namanzi adibeneyo, uze wome kwi-50 ° C. Isityalo sachithwa, i-5 g ye-powder ecocekileyo ifakwe kwi-100 ml yamanzi adibeneyo kwaye ixutywe kwi-70 ° C i-20 min ukufumana isicatshulwa. Isicatshulwa esifunyenweyo se-Bacillus nicotianae sahluzwa ngephepha le-Whatman lokucoca kwaye ligcinwe kwiityhubhu ezicocekileyo kunye nezintsholongwane kwi-4 ° C ukuze zisetyenziswe ngakumbi.
Njengoko kuboniswe kwi-Figure 1, i-GO yenziwe kwi-graphite powder ngendlela ye-Hummers elungisiweyo. I-10 mg ye-GO powder yachithwa kwi-50 ml yamanzi adibeneyo kwi-30 min phantsi kwe-sonication, kwaye emva koko i-0.9 g ye-FeCl3 kunye ne-2.9 g ye-NaAc ixutywe kwi-60 min. I-20 ml ye-atriplex yeqabunga yeqabunga yongezwa kwisisombululo esichukumisayo ngokuvuselela kwaye ishiywe kwi-80 ° C ngeeyure ze-8. Isiphumo sokunqunyanyiswa okumnyama kwahluzwa. I-nanocomposites elungiselelwe ihlanjwe nge-ethanol kunye namanzi e-bidistilled kwaye yomiswa kwi-oven vacuum kwi-50 ° C kwiiyure ze-12.
Iifoto ezicwangcisiweyo nezedijithali ze-green synthesis ye-rGO/nZVI kunye ne-nZVI complexes kunye nokususwa kwe-DC antibiotics kumanzi angcolileyo usebenzisa i-Atriplex halimus extract.
Ngokufutshane, njengoko kubonisiwe kwiSazobe soku-1, i-10 ml yesisombululo se-iron chloride equlethe i-0.05 M Fe3+ ion yongezwa kwi-20 ml yesisombululo seqabunga elikrakrayo kwimizuzu engama-60 ngokufudumeza okuphakathi kunye nokuvuselela, emva koko isisombululo sathi emva koko safakwa kwi-centrifuged. I-14,000 rpm (i-Hermle, i-15,000 rpm) i-15 min ukunika amaqhekeza amnyama, awathi ke ahlamba amaxesha angama-3 nge-ethanol kunye namanzi adibeneyo aze amiswe kwi-oven vacuum kwi-60 ° C. ubusuku bonke.
Izityalo ezidityanisiweyo ze-rGO/nZVI kunye ne-nZVI composite ziphawulwe nge-UV-visible spectroscopy (T70/T80 uthotho UV/Vis spectrophotometers, PG Instruments Ltd, UK) kuluhlu lokuskena lwe-200-800 nm. Ukuhlalutya i-Topography kunye nobukhulu bokuhanjiswa kwe-rGO/nZVI kunye ne-nZVI Composites, i-TEM spectroscopy (JOEL, JEM-2100F, Japan, i-accelerating voltage 200 kV) isetyenzisiwe. Ukuvavanya amaqela asebenzayo anokuthi athathe inxaxheba kwiimveliso zezityalo ezijongene nokubuyisela kunye nenkqubo yokuzinzisa, i-FT-IR i-spectroscopy yenziwe (i-JASCO spectrometer kwi-4000-600 cm-1). Ukongezelela, i-zeta enokuthi ihlalutye i-analyzer (i-Zetasizer Nano ZS Malvern) yayisetyenziselwa ukufundisisa umrhumo womphezulu we-nanomaterials owenziweyo. Kwimilinganiso ye-X-ray ye-diffraction ye-nanomaterials engumgubo, i-X-ray diffractometer (i-X'PERT PRO, e-Netherlands) isetyenzisiwe, esebenza ngoku (40 mA), i-voltage (45 kV) kuluhlu lwe-2θ ukusuka kwi-20 ° ukuya kwi-80 ° kunye neCuKa1 radiation (\(\lambda =\ ) 1.54056 Ao). I-spectrometer ye-X-ray ye-dispersive (i-EDX) (imodeli ye-JEOL JSM-IT100) yayinoxanduva lokufunda ukubunjwa kwe-elemental xa kuqokelela i-Al K-α monochromatic X-rays ukusuka -10 ukuya kwi-1350 eV kwi-XPS, ubukhulu bebala 400 μm K-ALPHA (I-Thermo Fisher Scientific, e-USA) amandla okuhanjiswa kwe-spectrum epheleleyo yi-200 eV kunye ne-spectrum emxinwa yi-50 eV. Isampulu yomgubo icinezelwe kwisibambi sesampulu, esifakwe kwigumbi lokucoca. I-spectrum ye-C 1 isetyenziswe njengesalathisi kwi-284.58 eV ukumisela amandla okubopha.
Uvavanyo lwe-Adsorption lwenziwa ukuvavanya ukusebenza kwe-rGO/nZVI nanocomposites eyenziweyo ekususeni i-doxycycline (DC) kwizisombululo ezinamanzi. Uvavanyo lwe-Adsorption lwenziwa kwi-25 ml yeeflaski ze-Erlenmeyer ngesantya sokungcangcazela se-200 rpm kwi-orbital shaker (i-Stuart, i-Orbital Shaker / SSL1) kwi-298 K. Ngokuxutywa kwesisombululo sesitokhwe se-DC (1000 ppm) ngamanzi ane-bidistilled. Ukuvavanya umphumo we-rGO / nSVI dosage kwi-adsorption performance, i-nanocomposites yobunzima obuhlukeneyo (0.01-0.07 g) yongezwa kwi-20 ml yesisombululo se-DC. Ukufunda i-kinetics kunye ne-adsorption isotherms, i-0.05 g ye-adsorbent igxininiswe kwisisombululo esinamanzi se-CD kunye nokugxilwa kokuqala (25-100 mg L-1). Impembelelo ye-pH ekususweni kwe-DC yafundwa kwi-pH (3-11) kunye nokuxinwa kokuqala kwe-50 mg L-1 kwi-25 ° C. Lungisa i-pH yenkqubo ngokongeza inani elincinci le-HCl okanye i-NaOH isisombululo (i-Crison pH meter, i-pH meter, i-pH 25). Ukongeza, impembelelo yobushushu bokusabela kwimvavanyo ye-adsorption kuluhlu lwe-25-55 ° C yaphandwa. Impembelelo yamandla e-ionic kwinkqubo ye-adsorption yafundwa ngokudibanisa iindidi ezahlukeneyo ze-NaCl (0.01-4 mol L-1) kwinqanaba lokuqala le-DC ye-50 mg L-1, pH 3 kunye ne-7), i-25 ° C, kunye idosi ye-adsorbent ye-0.05 g. I-adsorption ye-DC engeyiyo i-adsorbed yalinganiswa ngokusebenzisa i-double beam UV-Vis spectrophotometer (T70 / T80 series, PG Instruments Ltd, UK) ixhotyiswe nge-1.0 cm ubude bendlela ye-quartz cuvettes kwi-wavelengths ephezulu (λmax) ye-270 kunye ne-350 nm. Ipesenti yokususwa kwe-DC antibiotics (R%; Eq. 1) kunye nenani le-adsorption ye-DC, qt, Eq. I-2 (mg/g) yalinganiswa kusetyenziswa le nxaki ilandelayo.
apho i-% R ngumthamo wokususwa kwe-DC (%), i-Co yi-concentration yokuqala ye-DC ngexesha le-0, kunye ne-C yi-DC concentration ngexesha t, ngokulandelanayo (mg L-1).
apho i-qe isixa-mali se-DC adsorbed ngeyunithi yobunzima be-adsorbent (mg g-1), i-Co kunye ne-Ce zizigxina ze-zero ngexesha kunye nokulingana, ngokulandelelana (mg l-1), V ngumthamo wesisombululo (l) , kwaye m yi-adsorption mass reagent (g).
Imifanekiso ye-SEM (Amakhiwane 2A–C) abonisa i-lamellar morphology ye-rGO/nZVI edityanisiweyo ene-spherical iron nanoparticles esasazwe ngokufanayo kumphezulu wayo, ebonisa uncamathiselo oluyimpumelelo lwe-nZVI NPs kumphezulu we-rGO. Ukongezelela, kukho imibimbi kwiqabunga le-rGO, eqinisekisa ukususwa kwamaqela aqukethe i-oksijeni ngaxeshanye nokubuyiselwa kwe-A. halimus GO. Le mibimbi mikhulu isebenza njengeendawo zokulayishwa okusebenzayo kwee-iron NPs. Imifanekiso ye-nZVI (Umfanekiso we-2D-F) ibonise ukuba i-NP ye-iron engqukuva isasazeke kakhulu kwaye ayizange idityaniswe, nto leyo ibangelwa ukugquma kwezixhobo zebhotani zesicatshulwa sesityalo. Ubungakanani be-particle yahluka ngaphakathi kwe-15-26 nm. Nangona kunjalo, eminye imimandla ine-mesoporous morphology enesakhiwo se-bulges kunye ne-cavities, enokubonelela nge-adsorption ephezulu esebenzayo ye-nZVI, kuba inokunyusa amathuba okubambisa ii-molecule ze-DC kumphezulu we-NZVI. Xa i-extract ye-Rosa Damascus isetyenziselwa ukuhlanganiswa kwe-nZVI, i-NPs efunyenweyo yayingenakulinganiswa, kunye ne-voids kunye nemilo eyahlukeneyo, eyanciphisa ukusebenza kwayo kwi-Cr (VI) i-adsorption kunye nokwandisa ixesha lokuphendula i-23. Iziphumo ziyahambelana neNZVI eyenziwe yavela kwi-oki kunye namagqabi e-mulberry, eyona i-nanoparticles engqukuva enobukhulu obahlukeneyo beenanometer ngaphandle kokudityaniswa okucacileyo.
SEM imifanekiso ye rGO/nZVI (AC), nZVI (D, E) composite kunye ne EDX ipatheni zenZVI/rGO (G) kunye neZVI (H) composite.
Ukubunjwa kwe-elemental yezityalo ezenziwe nge-rGO/nZVI kunye ne-nZVI composites zafundwa kusetyenziswa i-EDX (Umfanekiso 2G, H). Uphononongo lubonisa ukuba i-NZVI iqulethwe ngekhabhoni (38.29% ngobunzima), ioksijini (47.41% ngobunzima) kunye nentsimbi (11.84% ngobunzima), kodwa ezinye izinto ezifana ne-phosphorus24 zikwakhona, ezinokufumaneka kwiincindi zezityalo. Ukongezelela, ipesenteji ephezulu yekhabhoni kunye ne-oksijini ngenxa yobukho beekhemikhali ze-phytochemicals ezivela kwizityalo zezityalo kwiisampuli ze-nZVI ezingaphantsi komhlaba. Ezi zinto zisasazwa ngokulinganayo kwi-rGO kodwa ngokwemilinganiselo eyahlukileyo: C (39.16 wt %), O (46.98 wt %) kunye ne Fe (10.99 wt %), EDX rGO/nZVI ikwabonisa ubukho bezinye izinto ezifana ne-S, leyo inokudityaniswa nezicatshulwa zezityalo, zisetyenziswa. Umlinganiselo wangoku we-C:O kunye nomxholo wentsimbi kwi-rGO/nZVI composite usebenzisa i-A. halimus ingcono kakhulu kunokusebenzisa i-eucalyptus leaf extract, njengoko ibonisa ukubunjwa kwe-C (23.44 wt.%), O (68.29 wt.%) kunye neFe (8.27 wt.%). wt %) 25. UNataša et al., 2022 unike ingxelo efanayo yokwakheka kwe-nZVI eyenziwe kumagqabi e-oki kunye ne-mulberry kwaye yaqinisekisa ukuba amaqela e-polyphenol kunye nezinye iimolekyuli eziqulethwe kwisicatshulwa samagqabi zinoxanduva lwenkqubo yokunciphisa.
I-morphology ye-NZVI idityaniswe kwizityalo (Fig. S2A,B) yayingqukuva kwaye yayingalungelelananga ngokuyinxenye, kunye ne-avareji yobungakanani besuntswana le-23.09 ± 3.54 nm, kodwa udityaniso lwekhonkco luye lwabonwa ngenxa ye-van der Waals forces kunye ne-ferromagnetism. Le milo ye-granular kunye ne-spherical yamasuntswana ikwisivumelwano esihle kunye neziphumo ze-SEM. Ukuqwalaselwa okufanayo kwafunyanwa ngu-Abdelfatah et al. ngo-2021 xa i-castor bean leaf extract isetyenziswe kwi-synthesis ye-nZVI11. I-Ruelas tuberosa isicatshulwa seqabunga i-NPs esetyenziswa njenge-agent yokunciphisa kwi-nZVI nayo inokwakheka kwe-spherical kunye nobubanzi be-20 ukuya kwi-40 nm26.
I-Hybrid rGO/nZVI ehlanganisiweyo yemifanekiso ye-TEM (Umfanekiso we-S2C-D) ibonise ukuba i-rGO yinqwelomoya esisiseko enomphetho womda kunye nemibimbi ebonelela ngeendawo ezininzi zokulayisha zeNZVI NPs; le morphology ye-lamellar nayo iqinisekisa ukuveliswa ngempumelelo kwe-rGO. Ukongeza, ii-nZVI NPs zinemilo engqukuva kunye nobukhulu bamasuntswana ukusuka kwi-5.32 ukuya kwi-27 nm kwaye zifakwe kuluhlu lwe-rGO kunye nokusasazwa okufanayo. Isicatshulwa segqabi le-Eucalyptus sasetyenziselwa ukudibanisa i-Fe NPs/rGO; Iziphumo ze-TEM ziphinde zaqinisekisa ukuba imibimbi kumqolo we-rGO iphucule ukusasazwa kwe-Fe NPs ngaphezu kwe-Fe NPs ecocekileyo kwaye yandisa ukusebenza kwakhona kwee-composites. Iziphumo ezifanayo zafunyanwa nguBagheri et al. 28 xa i-composite yenziwe kusetyenziswa ubuchule be-ultrasonic nge-avareji ye-iron nanoparticle ubukhulu obumalunga ne-17.70 nm.
I-FTIR ye-spectra ye-A. halimus, nZVI, GO, rGO, kunye ne-rGO/nZVI composite zibonisiwe kwiFigs. 3A. Ubukho bamaqela asebenzayo angaphezulu kumagqabi e-A. halimus ibonakala kwi-3336 cm-1, ehambelana ne-polyphenols, kunye ne-1244 cm-1, ehambelana namaqela e-carbonyl aveliswa yiprotheni. Amanye amaqela afana ne-alkanes kwi-2918 cm-1, i-alkenes kwi-1647 cm-1 kunye ne-CO-O-CO izandiso kwi-1030 cm-1 nazo ziye zabonwa, zibonisa ubukho bezityalo ezisebenza njengee-agent zokutywina kwaye zinoxanduva lokubuyisela. ukusuka kwi-Fe2+ ukuya kwi-Fe0 kwaye yi-IYA ku-rGO29. Ngokubanzi, imbonakalo ye-nZVI ibonisa iincopho ezifanayo zokufunxa njengeswekile ekrakra, kodwa ngesikhundla esitshintshileyo kancinci. Ibhendi eqinile ibonakala kwi-3244 cm-1 ehambelana ne-OH yokwelula i-vibrations (phenols), i-peak kwi-1615 ihambelana ne-C = C, kunye neebhendi kwi-1546 kunye ne-1011 cm-1 zivela ngenxa yokwelula kwe-C = O (i-polyphenols kunye ne-flavonoids) , CN -amaqela e-amine amnandi kunye ne-aliphatic amines nayo yabonwa kwi-1310 cm-1 kunye ne-1190 cm-1, ngokulandelanayo13. I-spectrum ye-FTIR ye-GO ibonisa ubukho bamaqela amaninzi aqulethe i-oksijini ephezulu, kubandakanywa ne-alkoxy (CO) ibhendi yokwelula kwi-1041 cm-1, i-epoxy (CO) ibhendi yokwelula kwi-1291 cm-1, i-C = O yolula. ibhendi ye-C = C eyolula i-vibrations kwi-1619 cm-1, ibhendi kwi-1708 cm-1 kunye nebhendi ebanzi yeqela le-OH elinokwelula i-vibrations kwi-3384 cm-1 yavela, eqinisekiswa yindlela ephuculweyo ye-Hummers, eyenza ngempumelelo i-oxidizes. inkqubo yegraphite. Xa uthelekisa i-rGO kunye ne-rGO/nZVI composites kunye ne-GO spectra, ubukhulu bamaqela aqulethe i-oksijini, njenge-OH kwi-3270 cm-1, iyancipha kakhulu, ngelixa ezinye, ezifana ne-C=O kwi-1729 cm-1, ziphelele ngokupheleleyo. kuncitshisiwe. yanyamalala, ebonisa ukususwa ngempumelelo kwamaqela asebenzayo ane-oksijini kwi-GO nge-A. halimus extract. Iimpawu ezintsha ezibukhali ze-rGO kwi-C=C tension zibonwa malunga ne-1560 kunye ne-1405 cm-1, eqinisekisa ukucuthwa kwe-GO ukuya kwi-rGO. Ukwahluka ukusuka kwi-1043 ukuya kwi-1015 cm-1 kwaye ukusuka kwi-982 ukuya kwi-918 cm-1 kwabonwa, mhlawumbi ngenxa yokufakwa kwezinto zezityalo31,32. I-Weng et al., i-2018 iphinde yabona ukuthotywa okubalulekileyo kwamaqela asebenzayo e-oksijini kwi-GO, eqinisekisa ukubunjwa okuyimpumelelo kwe-rGO ngokuncitshiswa kwe-bioreduction, ekubeni i-eucalyptus isicatshulwa samagqabi, esasetyenziselwa ukudibanisa i-iron graphene oxide composites, ibonise i-spectra ye-FTIR esondeleyo yecandelo lezityalo. amaqela asebenzayo. 33 .
A. FTIR spectrum ye gallium, nZVI, rGO, GO, composite rGO/nZVI (A). I-Roentgenogrammy composites rGO, GO, nZVI kunye ne-rGO/nZVI (B).
Ukuqulunqwa kwe-rGO/nZVI kunye ne-nZVI composites kwaqinisekiswa kakhulu yi-X-ray diffraction pattern (Fig. 3B). I-high-intensity Fe0 peak yabonwa kwi-2Ɵ 44.5 °, ehambelana nesalathisi (110) (JCPDS no. 06-0696)11. Enye incopho kwi-35.1 ° ye-(311) indiza ibangelwa yi-magnetite Fe3O4, i-63.2 ° inokudibaniswa ne-Miller index ye-plane (440) ngenxa yobukho be-ϒ-FeOOH (JCPDS no. 17-0536)34. Ipatheni ye-X-ray ye-GO ibonisa ukuphakama okubukhali kwi-2Ɵ 10.3 ° kunye nenye incopho ye-21.1 °, ebonisa ukukhutshwa okupheleleyo kwegraphite kunye nokugqamisa ubukho bamaqela aqulethe i-oksijini ebusweni be-GO35. Iipateni ezihlanganisiweyo ze-rGO kunye ne-rGO/nZVI zirekhode ukunyamalala kweempawu ze-GO zencopho kunye nokwenziwa kweencopho ezibanzi ze-rGO kwi-2Ɵ 22.17 kunye ne-24.7° ye-rGO kunye ne-rGO/nZVI composites, ngokulandelelana, eqinisekisa ukubuyiswa ngempumelelo kwe-GO ngezicatshulwa zezityalo. Nangona kunjalo, kwipatheni ehlanganisiweyo ye-rGO/nZVI, iincopho ezongezelelweyo ezinxulunyaniswa neplani yelattice ye-Fe0 (110) kunye ne-bcc Fe0 (200) zabonwa kwi-44.9\(^\circ\) kunye ne-65.22\(^\circ\), ngokulandelelanayo. .
I-zeta enokuthi inokwenzeka phakathi kwe-ionic layer eqhotyoshelwe kumphezulu we-particle kunye nesisombululo samanzi esichaza iimpawu ze-electrostatic zento kunye nokulinganisa ukuzinza kwayo37. Uhlalutyo olunokubakho lweZeta lwezityalo ezenziwe nge-nZVI, GO, kunye ne-rGO/nZVI composites zibonise ukuzinza kwazo ngenxa yobukho beentlawulo ezimbi ze -20.8, -22, kunye -27.4 mV, ngokulandelanayo, kumphezulu wabo, njengoko kuboniswe kuMfanekiso S1A- C. . Iziphumo ezinjalo zihambelana neengxelo ezininzi ezikhankanya ukuba izisombululo eziqulethe amasuntswana anexabiso le-zeta elinokubakho ngaphantsi kwe--25 mV ngokubanzi zibonisa izinga eliphezulu lokuzinza ngenxa yokunyanzeliswa kwe-electrostatic phakathi kwala masuntswana. Indibaniselwano ye-rGO kunye ne-nZVI ivumela umdibaniso ukuba ufumane amaxabiso abi kakhulu kwaye ke unozinzo oluphezulu kune-GO okanye i-NZVI yodwa. Ke ngoko, isenzeko sokugxothwa kwe-electrostatic siya kukhokelela ekwakhiweni kwee-composites ze-rGO/nZVI39 ezizinzile. Indawo engalunganga ye-GO ivumela ukuba isasazwe ngokulinganayo kwindawo enamanzi ngaphandle kwe-agglomeration, eyenza iimeko ezifanelekileyo zokusebenzisana ne-nZVI. Umrhumo ongalunganga unokunxulunyaniswa nobukho bamaqela ahlukeneyo asebenzayo kwisicatshulwa se-melon ekrakra, eqinisekisa kwakhona ukusebenzisana phakathi kwe-GO kunye ne-iron precursors kunye nesicatshulwa sesityalo ukwenza i-rGO kunye ne-nZVI, ngokulandelanayo, kunye ne-rGO/nZVI complex. Ezi zityalo zezityalo zinokuthi zisebenze njenge-capping agents, njengoko zithintela ukuhlanganiswa kwee-nanoparticles ezibangelwayo kwaye ngaloo ndlela zandise ukuzinza kwazo40.
Ukuqulunqwa kwe-elemental kunye neemeko ze-valence ze-nZVI kunye ne-rGO/nZVI composites zigqitywe yi-XPS (umzobo 4). Uphononongo lulonke lwe-XPS lubonise ukuba i-rGO/nZVI idityanisiwe iqulunqwe ikakhulu ziziqalelo C, O, kunye ne-Fe, ehambelana nemephu ye-EDS (Fig. 4F–H). I-spectrum ye-C1s iqukethe iincopho ezintathu kwi-284.59 eV, i-286.21 eV kunye ne-288.21 eV emele i-CC, i-CO kunye ne-C = O, ngokulandelanayo. I-spectrum ye-O1s yahlulahlulwe yaba ziincopho ezintathu, kubandakanywa i-531.17 eV, i-532.97 eV, kunye ne-535.45 eV, eyabelwe i-O=CO, i-CO, kunye ne-NO amaqela, ngokulandelanayo. Nangona kunjalo, iincopho ze-710.43, 714.57 kunye ne-724.79 eV zibhekisela kwi-Fe 2p3 / 2, i-Fe + 3 kunye ne-Fe p1 / 2, ngokulandelanayo. I-XPS spectra ye-nZVI (Fig. 4C-E) ibonise iincopho zezinto C, O, kunye noFe. I-Peaks kwi-284.77, i-286.25, kunye ne-287.62 eV iqinisekisa ubukho be-iron-carbon alloys, njengoko bebhekisela kwi-CC, C-OH, kunye ne-CO, ngokulandelanayo. I-spectrum ye-O1 ihambelana neencopho ezintathu ze-C-O / i-iron carbonate (531.19 eV), i-hydroxyl radical (532.4 eV) kunye ne-O-C = O (533.47 eV). I-peak kwi-719.6 ibangelwa yi-Fe0, ngelixa i-FeOOH ibonisa i-717.3 kunye ne-723.7 eV, ngaphezu koko, i-peak ye-725.8 eV ibonisa ubukho be-Fe2O342.43.
Izifundo ze-XPS ze-nZVI kunye ne-rGO/nZVI composites, ngokulandelelana (A, B). Imbonakalo epheleleyo ye-nZVI C1s (C), Fe2p (D), kunye ne-O1s (E) kunye ne-rGO/nZVI C1s (F), Fe2p (G), O1s (H) indibaniselwano.
I-N2 adsorption/desorption isotherm (Fig. 5A, B) ibonisa ukuba i-nZVI kunye ne rGO/nZVI composite zezodidi II. Ukongezelela, indawo ethile yendawo (SBET) ye-nZVI inyuke ukusuka kwi-47.4549 ukuya kwi-152.52 m2 / g emva kokuyimfama nge-rGO. Esi siphumo sinokuchazwa ngokuhla kweempawu zemagneti ze-NZVI emva kokumfamekisa kwe-rGO, ngaloo ndlela kuncitshiswa ukudityaniswa kwamasuntswana kunye nokwandisa indawo yomphezulu we-composites. Ukongezelela, njengoko kuboniswe kwi-Fig. 5C, umthamo we-pore (8.94 nm) we-rGO / nZVI composite iphezulu kuneyokuqala ye-NZVI (2.873 nm). Esi siphumo sivumelana no-El-Monaem et al. 45 .
Ukuphonononga umthamo we-adsorption yokususa i-DC phakathi kwe-rGO/nZVI composites kunye ne-nZVI yoqobo ngokuxhomekeke ekwandeni koxinaniso lokuqala, uthelekiso lwenziwe ngokudibanisa idosi engaguqukiyo ye-adsorbent nganye (0.05 g) kwi-DC kwiindawo ezahlukeneyo zokuqala. Isisombululo esiphandiweyo [25]. -100 mg l–1] kuma-25°C. Iziphumo zibonise ukuba ukususwa kakuhle (94.6%) kwe-rGO/nZVI composite yayiphezulu kuneyeNZVI yasekuqaleni (90%) kwi-concentration ephantsi (25 mg L-1). Nangona kunjalo, xa ugxininiso lokuqala lonyuswa ukuya kwi-100 mg L-1, ukusebenza kakuhle kokususa i-rGO/nZVI kunye ne-NZVI yabazali yehle yaya kutsho kuma-70% kunye ne-65%, ngokulandelanayo (Umfanekiso 6A), onokuthi ubangelwe ziindawo ezimbalwa ezisebenzayo kunye nokuthotywa kwe amasuntswana e-nZVI. Ngokuchaseneyo, i-rGO/nZVI ibonise ukusebenza okuphezulu kokususwa kwe-DC, enokuba kungenxa yesiphumo sokusebenzisana phakathi kwe-rGO kunye ne-NZVI, apho iziza ezisebenzayo ezifumanekayo ze-adsorption ziphezulu kakhulu, kwaye kwimeko ye-rGO/nZVI, ngakumbi I-DC ingabhengezwa kune-nZVI esemgangathweni. Ukongeza, kumkhiwane. I-6B ibonisa ukuba umthamo we-adsorption we-rGO / nZVI kunye neengqungquthela ze-NZVI zanda ukusuka kwi-9.4 mg / g ukuya kwi-30 mg / g kunye ne-9 mg / g, ngokulandelanayo, ngokunyuka kweqondo lokuqala ukusuka kwi-25-100 mg / L. -1.1 ukuba 28.73 mg g-1. Ngoko ke, izinga lokususwa kwe-DC lalinxulunyaniswa kakubi kunye nogxininiso lokuqala lwe-DC, olubangelwa linani elilinganiselweyo lamaziko okusabela axhaswa yi-adsorbent nganye ye-adsorption kunye nokususwa kwe-DC kwisisombululo. Ngaloo ndlela, kunokugqityezelwa kwezi ziphumo ukuba i-rGO/nZVI edityanisiweyo inokusebenza okuphezulu kwe-adsorption kunye nokunciphisa, kwaye i-rGO ekuqulunqweni kwe-rGO/nZVI ingasetyenziswa zombini njenge-adsorbent kunye nempahla yokuthwala.
Ukusebenza kokususa kunye nomthamo we-DC we-adsorption ye-rGO/nZVI kunye ne-nZVI composite yaba (A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, idosi = 0.05 g], pH. kwi-adsorption capacity kunye ne-DC yokususa ukusebenza kakuhle kwi-rGO/nZVI Composites (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, idosi = 0.05 g].
Isisombululo i-pH yinto ebalulekileyo ekufundweni kweenkqubo ze-adsorption, kuba ichaphazela iqondo le-ionization, i-speciation, kunye ne-ionization ye-adsorbent. Uvavanyo lwenziwa kwi-25 ° C kunye ne-dose ye-adsorbent eqhubekayo (0.05 g) kunye ne-concentration yokuqala ye-50 mg L-1 kwi-pH (3-11). Ngokophononongo loncwadi46, i-DC yimolekyuli ye-amphiphilic enamaqela amaninzi asebenzayo (i-phenols, amaqela e-amino, i-alcohols) kumanqanaba ahlukeneyo e-pH. Ngenxa yoko, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumeneyo kumphezulu we-rGO/nZVI ehlanganisiweyo inokunxibelelana ngokwe-electrostatically kwaye inokubakho njenge-cations, i-zwitterions, kunye ne-anions, i-molecule ye-DC 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 ehlanganisiweyo inokunxibelelana ngokwe-electrostatically kwaye inokubakho njenge-cations, i-zwitterions, kunye ne-anions, i-molecule ye-DC 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 в заимодействовать электровика в заимодействовать электровие нов, цвиттер-ионов и анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер- ионный (DCH20) 3,3 < pH < 7,7 и анионный (DCH- или DC2-) при pH 7,7. Kangangokuba, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumeneyo kumphezulu we-rGO/nZVI composite inokunxibelelana ngokwe-electrostatically kwaye ingabakho ngokohlobo lwe-cations, zwitterions, kunye ne-anions; i-molecule ye-DC ikhona njenge-cation (DCH3 +) kwi-pH <3.3; ionic (DCH20) 3.3 < pH <7.7 kunye ne-anionic (DCH- okanye i-DC2-) kwi-pH 7.7.因此，DC 的各子种功能和rGO/nZVI 复合材料表面的相关结构可能会发生黙电相互作用，默给种给互给结给给给给町。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 的 种 功能 和 和 和 复合 材料 表面 相关 结构 可能 会 发生 静生 静生 静生性 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 им структур на поверхности rGO/nZVI катионов, цвиттер-ионов и анионов, а молекулы ДК являются катионными (ДЦГ3+) при рН < 3,3. Ke ngoko, imisebenzi eyahlukeneyo ye-DC kunye nezakhiwo ezinxulumeneyo kumphezulu we-rGO/nZVI composite inokungena kwi-electrostatic interactions kwaye ibekho ngohlobo lwee-cations, i-zwitterion, kunye ne-anions, ngelixa ii-molecule ze-DC ziyi-cationic (DCH3+) kwi-pH <3.3. Он существует в виде цвиттер-иона (DCH20) при 3,3 < pH < 7,7 и аниона (DCH- или DC2-) при pH 7,7. Ikhona njenge-zwitterion (DCH20) kwi-3.3 <pH <7.7 kunye ne-anion (DCH- okanye i-DC2-) kwi-pH 7.7.Ngokunyuka kwe-pH ukusuka kwi-3 ukuya kwi-7, umthamo we-adsorption kunye nokusebenza kakuhle kokususwa kwe-DC kunyuke ukusuka kwi-11.2 mg / g (56%) ukuya kwi-17 mg / g (85%) (umzobo 6C). Nangona kunjalo, njengoko i-pH inyuke ukuya kwi-9 kunye ne-11, umthamo we-adsorption kunye nokusebenza kakuhle kokususwa kwehle ngandlela-thile, ukusuka kwi-10.6 mg / g (53%) ukuya kwi-6 mg / g (30%), ngokulandelanayo. Ngokunyuka kwe-pH ukusuka kwisi-3 ukuya kwisi-7, ii-DCs ubukhulu becala bezikhona ngokohlobo lwezwitterions, nto leyo eyenze ukuba iphantse itsaleleke ngokungeyo-electrostatically okanye igxothwe nge-rGO/nZVI composites, ubukhulu becala yi-electrostatic interaction. Njengoko i-pH inyuka ngaphezu kwe-8.2, umphezulu we-adsorbent wahlawuliswa kakubi, ngoko ke amandla e-adsorption ayancipha kwaye ayancipha ngenxa ye-electrostatic repulsion phakathi kwe-doxycycline ehlawuliswa kakubi kunye nomphezulu we-adsorbent. Lo mkhwa ucebisa ukuba i DC adsorption kwi rGO/nZVI Composites ixhomekeke kakhulu pH, kwaye iziphumo zikwabonisa ukuba rGO/nZVI Composites zifanelekile njenge adsorbents phantsi kwe acidic kunye ne neutral condition.
Umphumo weqondo lokushisa kwi-adsorption yesisombululo samanzi se-DC senziwe kwi-25-55 ° C. Umzobo we-7A ubonisa umphumo wokunyuka kweqondo lokushisa ekusebenzeni kokususa i-antibiotics ye-DC kwi-rGO / nZVI, kucacile ukuba umthamo wokususa kunye nomthamo we-adsorption wenyuka ukusuka kwi-83.44% kunye ne-13.9 mg / g ukuya kwi-47% kunye ne-7.83 mg / g. , ngokulandelelanayo. Oku kuhla kubalulekileyo kunokubangelwa kukunyuka kwamandla okushisa e-DC ion, okukhokelela kwi-desorption47.
Impembelelo yeqondo lobushushu ekususeni ngokuSebenzayo kunye nesakhono se-Adsorption se-CD kwi-rGO/nZVI Composites (A) [Co = 50 mg L–1, pH = 7, idosi = 0.05 g], idosi ye-Adsorbent kwi-Effective yokuSuswa kunye ne-Effective yokuSuswa kwe-CD I-Initial Concentration kumthamo we-adsorption kunye nokusebenza kakuhle kokususwa kwe-DC 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, umthamo = 0.05 g].
Umphumo wokunyusa umthamo we-adsorbent ye-composite rGO / nZVI ukusuka kwi-0.01 g ukuya kwi-0.07 g ekusebenzeni kakuhle kokususa kunye nomthamo we-adsorption uboniswe kuMfanekiso. 7B. Ukunyuka kwedosi ye-adsorbent kwakhokelela ekunciphiseni umthamo we-adsorption ukusuka kwi-33.43 mg / g ukuya kwi-6.74 mg / g. Nangona kunjalo, ngokunyuka kwedosi ye-adsorbent ukusuka kwi-0.01 g ukuya kwi-0.07 g, ukususwa kokusebenza kakuhle kunyuka ukusuka kwi-66.8% ukuya kwi-96%, leyo, ngokufanelekileyo, inokudibaniswa nokunyuka kwenani lamaziko asebenzayo kwindawo ye-nanocomposite.
Umphumo wokugxilwa kokuqala kwi-adsorption capacity kunye nokusebenza kakuhle kokususa [25-100 mg L-1, 25 ° C, pH 7, dose 0.05 g] yafundwa. Xa ugxininiso lokuqala lonyuswa ukusuka kwi-25 mg L-1 ukuya kwi-100 mg L-1, ipesenti yokususa i-rGO / nZVI composite yehla ukusuka kwi-94.6% ukuya kwi-65% (umzobo 7C), mhlawumbi ngenxa yokungabikho komsebenzi ofunekayo. iindawo. . I-Adsorbs imilinganiselo emikhulu ye-DC49. Ngakolunye uhlangothi, njengoko i-concentration yokuqala yanda, umthamo we-adsorption wanda ukusuka kwi-9.4 mg / g ukuya kwi-30 mg / g kwaze kwaba yilapho ukulingana kufikeleleke (Umfanekiso we-7D). Oku kusabela kungenakuthintelwa kungenxa yokwanda kwamandla okuqhuba kunye noxinzelelo lokuqala lwe-DC olukhulu kunokumelana nokudluliselwa kwe-ion ubunzima be-DC ukufikelela kumphezulu we-50 we-rGO/nZVI composite.
Ixesha loqhagamshelwano kunye nezifundo zekinetic zijolise ekuqondeni ixesha elilinganayo le-adsorption. Okokuqala, inani le-DC elibhengeziweyo ngexesha lemizuzu yokuqala ye-40 yexesha loqhagamshelwano lalimalunga nesiqingatha semali iyonke i-adsorbed ngexesha lonke (imizuzu eyi-100). Ngelixa iimolekyuli zeDC ezikwisisombululo zingqubana zibangela ukuba zifudukele ngokukhawuleza kumphezulu we-rGO/nZVI composite ekhokelela kwintengiso ebalulekileyo. Emva kwemizuzu engama-40, i-DC adsorption yanda ngokuthe ngcembe kwaye ngokukhawuleza kwaze kwaba yilapho ukulingana kwafikelelwa emva kwe-60 min (Umfanekiso 7D). Ekubeni isixa esifanelekileyo sibhengezwa kwimizuzu yokuqala ye-40, kuya kubakho ukungqubana okumbalwa kunye ne-DC molecule kunye neendawo ezimbalwa ezisebenzayo ziya kufumaneka kwii-molecule ezingenayo i-adsorbed. Ke ngoko, izinga le-adsorption lingancitshiswa51.
Ukuqonda kakuhle i-adsorption kinetics, iiplani zemigca ye-pseudo yokuqala (umzobo 8A), umyalelo wesibini we-pseudo (umzobo 8B), kunye no-Elovich (umzobo 8C) imodeli ye-kinetic yasetyenziswa. Ukususela kwiiparameters ezifunyenwe kwizifundo ze-kinetic (Itheyibhile S1), kuyacaca ukuba imodeli ye-pseudosecond imodeli engcono kakhulu yokuchaza i-adsorption kinetics, apho ixabiso le-R2 libekwe phezulu kunezinye iimodeli ezimbini. Kukwakho ukufana phakathi komthamo obaliweyo we-adsorption (qe, cal). Umyalelo we-pseudo-yesibini kunye namaxabiso okulinga (qe, exp.) bubungqina obungakumbi bokuba i-pseudo-second order iyimodeli engcono kunezinye iimodeli. Njengoko kubonisiwe kwiThebhile 1, ixabiso le-α (izinga le-adsorption yokuqala) kunye ne-β (i-desorption constant) iqinisekisa ukuba izinga le-adsorption liphezulu kune-desorption rate, ebonisa ukuba i-DC idla ngokubhengeza ngokufanelekileyo kwi-composite ye-rGO/nZVI52. .
I-Linear adsorption kinetic plots ye-pseudo-second order (A), i-pseudo-first order (B) kunye ne-Elovich (C) [Co = 25-100 mg l-1, pH = 7, T = 25 °C, umthamo = 0.05 g ].
Izifundo ze-adsorption isotherms zinceda ukufumanisa umthamo we-adsorption we-adsorbent (i-RGO/nRVI composite) kwiindawo ezahlukeneyo ze-adsorbate (DC) kunye nobushushu benkqubo. Umthamo omkhulu we-adsorption ubalwa usebenzisa i-isotherm ye-Langmuir, ebonisa ukuba i-adsorption yayiyi-homogeneous kwaye ibandakanya ukubunjwa kwe-monolayer ye-adsorbate ebusweni be-adsorbent ngaphandle kokusebenzisana phakathi kwabo53. Ezinye iimodeli ezimbini ze-isotherm ezisetyenziswa ngokubanzi ziimodeli zeFreundlich kunye neTemkin. Nangona imodeli ye-Freundlich ingasetyenziselwa ukubala umthamo we-adsorption, inceda ukuqonda inkqubo ye-adsorption ye-heterogeneous kunye nokuba izithuba kwi-adsorbent zinamandla ahlukeneyo, ngelixa imodeli ye-Temkin inceda ukuqonda iimpawu zomzimba kunye neekhemikhali ze-adsorption54.
Amanani 9A-C abonisa iiplani zemigca yeemodeli zeLangmuir, Freindlich, kunye neTemkin, ngokulandelanayo. Amaxabiso e-R2 abalwe ukusuka kwiFreundlich (Fig. 9A) kunye neLangmuir (Fig. 9B) iiplani zomgca kwaye ziboniswe kwiThebhile 2 zibonisa ukuba i-adsorption ye-DC kwi-rGO/nZVI composite ilandela i-Freundlich (0.996) kunye ne-Langmuir (0.988) isotherm iimodeli kunye neTemkin (0.985). Umthamo omkhulu we-adsorption (qmax), ubalwa kusetyenziswa imodeli ye-isotherm ye-Langmuir, yayingu-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 efanelekileyo. Ngaphandle koko, i-Freundlich eqhubekayo (n = 2.756) ibonisa ukhetho lwale nkqubo yokufunxa. Ngokomzekelo womgca we-isotherm ye-Temkin (Fig. 9C), i-adsorption ye-DC kwi-rGO/nZVI composite yinkqubo ye-adsorption ebonakalayo, kuba u-b yi-82 kJ mol-1 (0.408)55. Nangona i-adsorption yomzimba idla ngokulawulwa ngamandla abuthathaka e-van der Waals, i-adsorption yangoku ngqo kwi-rGO/nZVI Composites ifuna amandla aphantsi e-adsorption [56, 57].
I-Freundlich (A), i-Langmuir (B), kunye ne-Temkin (C) i-isotherms ye-adsorption ye-linear [Co = 25-100 mg L-1, pH = 7, T = 25 °C, i-dose = 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 isiphumo sotshintsho lobushushu bempendulo kukususwa kweDC kwicomposites yerGO/nZVI, iparameters zethermodynamic ezifana notshintsho entropy (ΔS), enthalpy change (ΔH), kunye notshintsho lwamandla simahla (ΔG) zibaliwe ukusuka kwi-equations. 3 kunye nama-458.
apho \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) - i-thermodynamic equilibrium constant, Ce kunye ne-CAe - rGO kwisisombululo, ngokulandelelanayo /nZVI DC izigxinaniso kumphezulu wolungelelwaniso. I-R kunye ne-RT yi-gas engatshintshiyo kunye nobushushu be-adsorption, ngokulandelelanayo. Ukucwangcisa i-ln Ke ngokuchasene ne-1/T kunika umgca othe ngqo (Fig. 9D) apho u-∆S kunye no-∆H kunokumiselwa khona.
Ixabiso elibi ΔH libonisa ukuba inkqubo iyingozi kakhulu. Ngakolunye uhlangothi, ixabiso le-ΔH lingaphakathi kwenkqubo ye-adsorption ebonakalayo. Amaxabiso angalunganga we-ΔG kwiThebhile 3 abonisa ukuba i-adsorption iyenzeka kwaye iyazenzekela. Amaxabiso angalunganga we-ΔS abonisa ukucwangciswa okuphezulu kweemolekyuli ze-adsorbent kujongano lwamanzi (Itheyibhile 3).
Itheyibhile ye-4 ithelekisa i-rGO/nZVI edibeneyo kunye nezinye ii-adsorbents ezichazwe kwizifundo zangaphambili. Kucacile ukuba i-VGO/nCVI composite inomthamo ophezulu we-adsorption kwaye ingaba yinto ethembisayo yokususwa kwe-antibiotics ye-DC emanzini. Ukongeza, i-adsorption ye-rGO/nZVI Composites yinkqubo ekhawulezayo kunye nexesha lokulinganisa le-60 min. Ezona mpawu zentengiso zigqwesileyo ze-rGO/nZVI zidibanisi zingachazwa ngesiphumo se-synergistic ye-rGO kunye ne-nZVI.
Amanani 10A, B abonisa indlela enengqiqo yokususwa kwe-DC antibiotics nge-rGO/nZVI kunye ne-nZVI complexes. Ngokweziphumo zovavanyo kwisiphumo se-pH ekusebenzeni kakuhle kwe-DC adsorption, ngokunyuka kwe-pH ukusuka kwi-3 ukuya kwi-7, i-adsorption ye-DC kwi-rGO/nZVI composite ayizange ilawulwe yi-electrostatic interactions, ekubeni yayisebenza njenge-zwitterion; ngoko ke, utshintsho kwixabiso le-pH aluzange luchaphazele inkqubo ye-adsorption. Emva koko, indlela ye-adsorption inokulawulwa ngonxibelelwano olungeyo-electrostatic olufana ne-hydrogen bonding, iziphumo ze-hydrophobic, kunye ne-π-π yokuhlangana kwe-stacking phakathi kwe-rGO/nZVI composite kunye ne-DC66. Yaziwa kakuhle into yokuba umatshini we-adsorbates enevumba elimnandi kumphezulu we-graphene ebekwe umaleko ichazwe ngu-π–π wokupakisha ukudibana njengowona mandla aqhubayo. I-composite yimathiriyeli elelelweyo efana negraphene enobuninzi bokufunxa kwi-233 nm ngenxa yotshintsho π-π*. Ngokusekwe kubukho bamakhonkco amane anevumba elimnandi kulwakhiwo lwemolekyuli ye-DC adsorbate, siye saqikelela ukuba kukho indlela yokudibana kwe-π-π-stacking phakathi kwe-DC enevumba elimnandi (π-electron receiver) kunye nommandla otyebileyo ngee-electrons π. umphezulu we-RGO. /nZVI imidibaniso. Ukongeza, njengoko kubonisiwe kwifig. I-10B, izifundo ze-FTIR zenziwa ukufunda ukudibana kwemolekyuli ye-rGO/nZVI composites kunye ne-DC, kunye nembonakalo ye-FTIR ye-rGO/nZVI edityanisiweyo emva kwe-adsorption ye-DC ibonisiwe kuMfanekiso 10B. 10b. Incopho entsha ibonwa kwi-2111 cm-1, ehambelana nesakhelo sokungcangcazela kwe-C = C bond, ebonisa ubukho bamaqela asebenzayo ahambelanayo ebusweni be-67 rGO/nZVI. Ezinye iincopho zisuka kwi-1561 ukuya kwi-1548 cm-1 kunye ne-1399 ukuya kwi-1360 cm-1, ekwaqinisekisa ukuba ukusebenzisana kwe-π-π kudlala indima ebalulekileyo kwi-adsorption ye-graphene kunye ne-organic pollutants68,69. Emva kwe-DC adsorption, ukuqina kwamanye amaqela aqulethe i-oksijini, njenge-OH, yehla ukuya kwi-3270 cm-1, ebonisa ukuba i-hydrogen bonding yenye yeendlela zokubhengezwa. Ngoko ke, ngokusekwe kwiziphumo, i-adsorption ye-DC kwi-rGO/nZVI composite yenzeka ikakhulu ngenxa ye-π-π yokupakishwa konxibelelwano kunye neebhondi ze-H.
Ingqiqo yendlela yokubhengezwa kwe-DC antibiotics nge-rGO/nZVI kunye ne-nZVI complexes (A). I-FTIR adsorption spectra ye DC kwi rGO/nZVI kunye ne nZVI (B).
Ubunzulu bebhanti zokufunxa ze-NZVI kwi-3244, 1615, 1546, kunye ne-1011 cm-1 zonyuka emva kokufakwa kwe-DC kwi-nZVI (Fig. 10B) xa kuthelekiswa ne-NZVI, ekufuneka inxulumane nentsebenziswano kunye namaqela asebenzayo e-carboxylic acid. O amaqela kwi-DC. Nangona kunjalo, le pesenti isezantsi yosulelo kuzo zonke iibhendi eziqatshelweyo zibonisa ukuba akukho tshintsho lubalulekileyo kwi-adsorption ye-adsorbent ye-phytosynthetic adsorbent (nZVI) xa kuthelekiswa ne-NZVI phambi kwenkqubo ye-adsorption. Ngokophando lokususwa kwe-DC kunye ne-nZVI71, xa i-nZVI isabela nge-H2O, ii-electron ziyakhutshwa kwaye emva koko i-H+ isetyenziselwa ukuvelisa i-hydrogen esebenzayo enokuncitshiswa kakhulu. Ekugqibeleni, ezinye iikhompawundi ze-cationic zamkela ii-electron ezisuka kwi-hydrogen esebenzayo, ezikhokelela ku--C=N kunye no -C=C-, okubalelwa kukwahlulwa kweringi ye-benzene.
Ixesha lokuposa: Nov-14-2022