Zikomo pochezera Nature.com. Mtundu wa msakatuli womwe mukugwiritsa ntchito uli ndi chithandizo chochepa cha CSS. Kuti mumve zambiri, tikupangira kuti mugwiritse ntchito msakatuli wosinthidwa (kapena kuletsa Compatibility Mode mu Internet Explorer). Pakadali pano, kuti tithandizire kupitilizabe, tidzapereka tsambalo popanda masitayilo ndi JavaScript.
Mu ntchitoyi, ma composite a rGO/nZVI adapangidwa koyamba pogwiritsa ntchito njira yosavuta komanso yogwirizana ndi chilengedwe pogwiritsa ntchito tsamba la Sophora yellowish leaf monga chochepetsera komanso chokhazikika kuti agwirizane ndi mfundo za "green" chemistry, monga kaphatikizidwe kakang'ono ka mankhwala. Zida zingapo zakhala zikugwiritsidwa ntchito kutsimikizira kuphatikizika kopambana kwa ma composite, monga SEM, EDX, XPS, XRD, FTIR, ndi kuthekera kwa zeta, zomwe zikuwonetsa kupanga kopambana kwamagulu. Kuthekera kochotsa kwa zophatikizika za bukuli ndi NZVI yoyera pamayambiriro osiyanasiyana a maantibayotiki a doxycycline adafaniziridwa ndi kufufuza momwe rGO ndi NZVI imathandizira. Pansi pa kuchotsedwa kwa 25mg L-1, 25°C ndi 0.05g, kuchuluka kwa zotsatsa za NZVI koyera kunali 90%, pomwe kuchuluka kwa adsorptive kuchotsa doxycycline ndi gulu la rGO/nZVI kunafika 94.6%, kutsimikizira kuti NZVI ndi rGO . Njira yotsatsira imagwirizana ndi dongosolo la pseudo-yachiwiri ndipo ikugwirizana bwino ndi chitsanzo cha Freundlich chokhala ndi mphamvu yowonjezereka ya 31.61 mg g-1 pa 25 ° C ndi pH 7. Njira yomveka yochotsera DC yaperekedwa. Kuphatikiza apo, kugwiritsidwanso ntchito kwa gulu la rGO/nZVI kunali 60% pambuyo pazaka zisanu ndi chimodzi zotsatizana zosinthikanso.
Kusoŵa kwa madzi ndi kuipitsa tsopano kuli chiwopsezo chachikulu m’maiko onse. M'zaka zaposachedwa, kuyipitsidwa kwamadzi, makamaka kuyipitsidwa kwa maantibayotiki, kwawonjezeka chifukwa chakuchulukirachulukira komanso kumwa mowa panthawi ya mliri wa COVID-191,2,3. Chifukwa chake, kupanga ukadaulo wogwira mtima wochotsa maantibayotiki m'madzi oyipa ndi ntchito yofunika kwambiri.
Mmodzi mwa maantibayotiki olimbana ndi semisynthetic ochokera ku gulu la tetracycline ndi doxycycline (DC)4,5. Zanenedwa kuti zotsalira za DC m'madzi apansi ndi pamwamba pa madzi sangathe kusinthidwa, 20-50% yokha imapangidwa ndi zitsulo ndipo zina zimatulutsidwa m'chilengedwe, zomwe zimayambitsa mavuto aakulu a chilengedwe ndi thanzi6.
Kuwonekera kwa DC pamiyeso yotsika kumatha kupha tizilombo tating'onoting'ono ta m'madzi, kuwopseza kufalikira kwa mabakiteriya opha tizilombo toyambitsa matenda, ndikuwonjezera kukana kwa antimicrobial, kotero choipitsachi chiyenera kuchotsedwa m'madzi onyansa. Kuwonongeka kwachilengedwe kwa DC m'madzi ndi njira yochepa kwambiri. Njira za physico-chemical monga photolysis, biodegradation ndi adsorption zingangowonongeka pazigawo zochepa komanso pamtengo wotsika kwambiri7,8. Komabe, njira yotsika mtengo kwambiri, yosavuta, yokonda zachilengedwe, yosavuta kugwira komanso yothandiza kwambiri ndi adsorption9,10.
Nano zero valent iron (nZVI) ndi chinthu champhamvu kwambiri chomwe chimatha kuchotsa maantibayotiki ambiri m'madzi, kuphatikiza metronidazole, diazepam, ciprofloxacin, chloramphenicol, ndi tetracycline. Kutha uku ndi chifukwa cha zinthu zodabwitsa zomwe NZVI ili nazo, monga kuyambiransoko, malo akulu, ndi malo ambiri omangira kunja11. Komabe, NZVI imakonda kuphatikizika m'ma media am'madzi chifukwa cha mphamvu za van der Wells komanso maginito apamwamba, zomwe zimachepetsa mphamvu yake pochotsa zowononga chifukwa chopanga zigawo za oxide zomwe zimalepheretsa kuyambiranso kwa nZVI10,12. Kuphatikizika kwa tinthu ta nZVI kumatha kuchepetsedwa posintha mawonekedwe awo ndi ma surfactants ndi ma polima kapena kuwaphatikizira ndi ma nanomatadium ena monga ma composites, omwe atsimikizira kuti ndi njira yabwino yopititsira patsogolo kukhazikika kwawo pa chilengedwe13,14.
Graphene ndi mbali ziwiri za carbon nanomaterial yopangidwa ndi maatomu a carbon sp2-hybridized omwe amakonzedwa mu zisa. Lili ndi malo akuluakulu, mphamvu zamakina kwambiri, ntchito yabwino kwambiri ya electrocatalytic, matenthedwe apamwamba kwambiri, kuyenda kwa ma elekitironi mofulumira, ndi zinthu zonyamulira zoyenera zothandizira nanoparticles pamtunda wake. Kuphatikiza kwa zitsulo za nanoparticles ndi graphene kumatha kupitilira phindu la munthu aliyense payekhapayekha ndipo, chifukwa champhamvu zake zakuthupi ndi zamankhwala, zimapereka kugawa koyenera kwa nanoparticles kuti athetse bwino madzi15.
Zotsalira za zomera ndi njira yabwino kwambiri yochepetsera mankhwala ovulaza omwe amagwiritsidwa ntchito popanga graphene oxide (rGO) ndi NZVI chifukwa akupezeka, otsika mtengo, sitepe imodzi, otetezeka ku chilengedwe, ndipo angagwiritsidwe ntchito ngati kuchepetsa. monga flavonoids ndi phenolic mankhwala amakhalanso ngati stabilizer. Choncho, Atriplex halimus L. tsamba la masamba linagwiritsidwa ntchito monga kukonza ndi kutseka kwa kaphatikizidwe ka rGO / nZVI composites mu phunziro ili. Atriplex halimus wochokera ku banja la Amaranthaceae ndi chitsamba chosatha chokonda nayitrogeni chokhala ndi malo osiyanasiyana16.
Malinga ndi zolemba zomwe zilipo, Atriplex halimus (A. halimus) idagwiritsidwa ntchito koyamba kupanga rGO/nZVI composites ngati njira yopezera ndalama komanso yogwirizana ndi chilengedwe. Choncho, cholinga cha ntchitoyi chili ndi zigawo zinayi: (1) phytosynthesis ya rGO/nZVI ndi makolo nZVI composites pogwiritsa ntchito A. halimus aquatic leaf extract, (2) mawonekedwe a phytosynthesized composites pogwiritsa ntchito njira zingapo kutsimikizira kupeka kwawo bwino, (3) ) kuphunzira za synergistic zotsatira za rGO ndi NZVI mu adsorption ndi kuchotsa zonyansa organic doxycycline maantibayotiki pansi magawo osiyanasiyana anachita, kukhathamiritsa zikhalidwe za ndondomeko adsorption, (3) kufufuza zipangizo gulu mu mankhwala osiyanasiyana mosalekeza pambuyo processing mkombero.
Doxycycline hydrochloride (DC, MM = 480.90, formula ya mankhwala C22H24N2O · HCl, 98%), iron chloride hexahydrate (FeCl3.6H2O, 97%), ufa wa graphite wogulidwa ku Sigma-Aldrich, USA. Sodium hydroxide (NaOH, 97%), ethanol (C2H5OH, 99.9%) ndi hydrochloric acid (HCl, 37%) anagulidwa ku Merck, USA. NaCl, KCl, CaCl2, MnCl2 ndi MgCl2 adagulidwa kuchokera ku Tianjin Comio Chemical Reagent Co., Ltd. Zonse zopangira zinthu ndizoyera kwambiri. Madzi osungunuka kawiri ankagwiritsidwa ntchito pokonzekera njira zonse zamadzimadzi.
Zoyimira zoyimira za A. halimus zasonkhanitsidwa kuchokera ku malo awo achilengedwe mumtsinje wa Nile Delta ndi malo omwe ali m'mphepete mwa nyanja ya Mediterranean ku Egypt. Zomera zidasonkhanitsidwa motsatira malangizo adziko lonse komanso apadziko lonse lapansi17. Prof. Manal Fawzi wapeza zitsanzo za zomera malinga ndi Boulos18, ndipo dipatimenti ya Environmental Sciences ya ku yunivesite ya Alexandria ikuvomereza kusonkhanitsa mitundu ya zomera zomwe zaphunziridwa kuti zigwiritsidwe ntchito ndi sayansi. Zitsanzo za ma voucha zimachitikira ku Tanta University Herbarium (TANE), ma vocha nos. 14 122–14 127, malo osungiramo zitsamba omwe amapereka mwayi wopeza zinthu zosungidwa. Kuphatikiza apo, kuti muchotse fumbi kapena dothi, dulani masamba a mmerawo kukhala tiziduswa tating'onoting'ono, tsukani katatu ndi mpopi ndi madzi osungunuka, ndiyeno muwume pa 50 ° C. Chomeracho chinaphwanyidwa, 5 g wa ufa wabwino umamizidwa mu 100 ml ya madzi osungunuka ndikugwedezeka pa 70 ° C kwa mphindi 20 kuti mupeze chotsitsa. Zomwe zinapezedwa za Bacillus nicotianae zidasefedwa kudzera mu pepala la Whatman fyuluta ndikusungidwa mu machubu oyera ndi osabala pa 4 ° C kuti agwiritsenso ntchito.
Monga momwe tawonetsera pa Chithunzi 1, GO idapangidwa kuchokera ku ufa wa graphite ndi njira yosinthidwa ya Hummers. 10 mg wa GO ufa anali omwazika mu 50 ml ya deionized madzi 30 min pansi sonication, ndiyeno 0,9 g wa FeCl3 ndi 2.9 g wa NaAc anali osakanizidwa 60 min. 20 ml ya atriplex tsamba Tingafinye anawonjezeredwa kuti analimbikitsa njira ndi oyambitsa ndi anasiya pa 80 ° C kwa 8 hours. Chotsatira kuyimitsidwa kwakuda kunasefedwa. Ma nanocomposites okonzedwa adatsukidwa ndi ethanol ndi madzi otsekemera ndikuwumitsa mu uvuni wa vacuum pa 50 ° C kwa maola 12.
Zithunzi zojambulidwa ndi digito za kaphatikizidwe kobiriwira kwa rGO/nZVI ndi nZVI ndi kuchotsedwa kwa maantibayotiki a DC m'madzi oipitsidwa pogwiritsa ntchito Atriplex halimus extract.
Mwachidule, monga tikuonera mkuyu. 1, 10 ml ya chitsulo kolorayidi njira munali 0,05 M Fe3+ ayoni anawonjezedwa dropwise kwa 20 ml ya owawa tsamba Tingafinye njira kwa mphindi 60 ndi zolimbitsa Kutentha ndi oyambitsa, ndiyeno yankho ndiye centrifuged pa. 14,000 rpm (Hermle , 15,000 rpm) kwa mphindi 15 kuti apereke tinthu takuda, zomwe zinatsuka nthawi 3 ndi ethanol ndi madzi osungunuka kenako zowuma mu uvuni wa vacuum pa 60 ° C. usiku wonse.
Zophatikiziridwa ndi zomera za rGO/nZVI ndi nZVI zinali ndi mawonekedwe owoneka bwino a UV (T70/T80 mndandanda wa UV/Vis spectrophotometers, PG Instruments Ltd, UK) pa sikani ya 200-800 nm. Kusanthula malo ndi kukula kwa rGO/nZVI ndi nZVI composites, TEM spectroscopy (JOEL, JEM-2100F, Japan, accelerating voltage 200 kV) anagwiritsidwa ntchito. Kuti muwunikire magulu ogwira ntchito omwe amatha kutenga nawo gawo pazomera zomwe zimayang'anira kubwezeretsa ndi kukhazikika, mawonekedwe a FT-IR adachitika (mawonekedwe a JASCO mumitundu ya 4000-600 cm-1). Kuphatikiza apo, zeta potential analyzer (Zetasizer Nano ZS Malvern) idagwiritsidwa ntchito powerengera kuchuluka kwa ma nanomatadium opangidwa. Pamiyezo ya X-ray ya diffraction ya powdered nanomaterials, X-ray diffractometer (X'PERT PRO, Netherlands) idagwiritsidwa ntchito, ikugwira ntchito pakali pano (40 mA), voltage (45 kV) mu 2θ kuyambira 20 ° mpaka 80 ° ndi ma radiation a CuKa1 (\(\lambda =\ ) 1.54056 Ao). The energy dispersive X-ray spectrometer (EDX) (model JEOL JSM-IT100) anali ndi udindo wowerengera zolemba zoyambirira posonkhanitsa ma X-ray a Al K-α monochromatic X kuchokera -10 mpaka 1350 eV pa XPS, kukula kwa malo 400 μm K-ALPHA (Thermo Fisher Scientific, USA) mphamvu yotumizira ya sipekitiramu yonse ndi 200 eV ndipo sipekitiramu yopapatiza ndi 50 eV. Chitsanzo cha ufacho chimakanikizidwa pa chotengera chachitsanzo, chomwe chimayikidwa mu chipinda cha vacuum. Sipekitiramu ya C 1 s idagwiritsidwa ntchito ngati cholozera pa 284.58 eV kudziwa mphamvu yomangirira.
Kuyesera kwa Adsorption kunachitika kuti ayese mphamvu ya rGO/nZVI nanocomposites pochotsa doxycycline (DC) ku mayankho amadzimadzi. Kuyesera kwa Adsorption kunachitika mu 25 ml Erlenmeyer flasks pa liwiro logwedezeka la 200 rpm pa orbital shaker (Stuart, Orbital Shaker / SSL1) pa 298 K. Mwa kusungunula njira ya DC stock solution (1000 ppm) ndi madzi a bidistilled. Kuti muwone zotsatira za mlingo wa rGO/nSVI pakuchita bwino kwa adsorption, ma nanocomposites a zolemera zosiyanasiyana (0.01-0.07 g) adawonjezeredwa ku 20 ml ya yankho la DC. Kuphunzira kinetics ndi adsorption isotherms, 0,05 g wa adsorbent kumizidwa mu amadzimadzi njira ya CD ndi koyamba ndende (25-100 mg wa L-1). Zotsatira za pH pakuchotsedwa kwa DC zinaphunziridwa pa pH (3-11) ndi ndende yoyamba ya 50 mg L-1 pa 25 ° C. Sinthani pH ya dongosolo mwa kuwonjezera pang'ono HCl kapena NaOH yankho (Crison pH mita, pH mita, pH 25). Kuphatikiza apo, chikoka cha kutentha kwamachitidwe pamayesero a adsorption osiyanasiyana a 25-55 ° C adafufuzidwa. Zotsatira za mphamvu ya ma ionic pa njira yotsatsira zidaphunziridwa powonjezera kuchuluka kwa NaCl (0.01-4 mol L-1) pamlingo woyamba wa DC wa 50 mg L-1, pH 3 ndi 7), 25 ° C, ndi Mlingo wa adsorbent ndi 0,05 g. Kutsatsa kwa DC yopanda adsorbed kudayezedwa pogwiritsa ntchito mtengo wapawiri UV-Vis spectrophotometer (T70/T80 mndandanda, PG Instruments Ltd, UK) yokhala ndi ma cuvettes a 1.0 cm kutalika kwa mafunde (λmax) a 270 ndi 350 nm. Kuchotsedwa kwa ma antibiotic a DC (R%; Eq. 1) ndi kuchuluka kwa adsorption ya DC, qt, Eq. 2 (mg/g) anayesedwa pogwiritsa ntchito equation zotsatirazi.
pomwe % R ndiye mphamvu yochotsa DC (%), Co ndiye ndende yoyambira ya DC panthawi 0, ndipo C ndiye ndende ya DC pa nthawi t, motsatana (mg L-1).
pomwe qe ndi kuchuluka kwa DC yotsatiridwa pa unit mass of adsorbent (mg g-1), Co ndi Ce ndizomwe zimakhazikika paziro nthawi komanso pamlingo, motsatana (mg l-1), V ndiye voliyumu yothetsera (l) , ndipo m ndi adsorption mass reagent (g).
Zithunzi za SEM (mkuyu 2A-C) zikuwonetsa mawonekedwe a lamellar ya rGO/nZVI yopangidwa ndi chitsulo chobulungira nanoparticles omwazikana pamwamba pake, kusonyeza bwino kulumikiza kwa NZVI NPs pa rGO pamwamba. Kuphatikiza apo, pali makwinya mu tsamba la rGO, kutsimikizira kuchotsedwa kwamagulu okhala ndi okosijeni nthawi imodzi ndi kubwezeretsedwa kwa A. halimus GO. Makwinya akuluwa amakhala ngati malo otsegulira ma NPs achitsulo. Zithunzi za nZVI (mkuyu 2D-F) zinawonetsa kuti NPs yachitsulo yozungulira inali yobalalika kwambiri ndipo sizinaphatikizidwe, zomwe zili chifukwa cha kuyanika kwa zigawo za botanical za chomeracho. Kukula kwa tinthu kumasiyanasiyana mkati mwa 15-26 nm. Komabe, madera ena ali ndi mawonekedwe a mesoporous morphology okhala ndi zotupa ndi zibowo, zomwe zimatha kupereka mwayi wotsatsa kwambiri wa NZVI, chifukwa amatha kukulitsa mwayi wotsekera mamolekyu a DC pamwamba pa NZVI. Pamene chotsitsa cha Rosa Damasiko chinagwiritsidwa ntchito popanga nZVI, ma NP omwe anapezeka anali osafanana, okhala ndi ma voids ndi mawonekedwe osiyanasiyana, omwe amachepetsa mphamvu yawo mu Cr(VI) adsorption ndikuwonjezera nthawi yochitira 23. Zotsatira zake zimagwirizana ndi nZVI yopangidwa kuchokera ku masamba a oak ndi mabulosi, omwe amakhala ndi nanoparticles ozungulira okhala ndi makulidwe osiyanasiyana a nanometer popanda kuphatikiza kowonekera.
Zithunzi za SEM za rGO/nZVI (AC), nZVI (D, E) kompositi ndi EDX mapatani a nZVI/rGO (G) ndi nZVI (H) kompositi.
Kapangidwe kake ka rGO/nZVI ndi nZVI kompositi yopangidwa ndi mbewu idaphunziridwa pogwiritsa ntchito EDX (Mkuyu 2G, H). Kafukufuku akuwonetsa kuti NZVI imapangidwa ndi kaboni (38.29% ndi misa), mpweya (47.41% ndi misa) ndi chitsulo (11.84% ndi misa), koma zinthu zina monga phosphorous24 zilipo, zomwe zingapezeke kuchokera ku zomera. Kuphatikiza apo, kuchuluka kwa kaboni ndi okosijeni kumachitika chifukwa cha kukhalapo kwa phytochemicals kuchokera kuzinthu zamitengo m'masampu apansi a nZVI. Zinthuzi zimagawidwa mofanana pa rGO koma mosiyanasiyana: C (39.16 wt %), O (46.98 wt %) ndi Fe (10.99 wt %), EDX rGO/nZVI imasonyezanso kupezeka kwa zinthu zina monga S, zomwe akhoza kugwirizanitsidwa ndi zokolola za zomera, zimagwiritsidwa ntchito. Chiŵerengero chamakono cha C:O ndi chitsulo mu gulu la rGO/nZVI pogwiritsa ntchito A. halimus ndichabwino kwambiri kuposa kugwiritsa ntchito masamba a bulugamu, monga momwe amapangidwira C (23.44 wt.%), O (68.29 wt.%) ndi Fe (8.27 wt.%). wt %) 25. Nataša et al., 2022 adanenanso za kapangidwe kofananako ka nZVI kopangidwa kuchokera ku masamba a oak ndi mabulosi ndikutsimikizira kuti magulu a polyphenol ndi mamolekyu ena omwe ali mutsamba lamasamba ndi omwe amachititsa kuchepetsa.
Mapangidwe a NZVI opangidwa muzomera (mkuyu. S2A, B) anali ozungulira komanso osakhazikika pang'ono, ndipo pafupifupi tinthu tating'onoting'ono ta 23.09 ± 3.54 nm, komabe maunyolo ang'onoang'ono adawonedwa chifukwa cha mphamvu za van der Waals ndi ferromagnetism. Mawonekedwe a tinthu tating'onoting'ono komanso ozungulirawa amagwirizana bwino ndi zotsatira za SEM. Kuwona kofananako kunapezedwa ndi Abdelfatah et al. mu 2021 pomwe masamba a castor adagwiritsidwa ntchito popanga nZVI11. Ruelas tuberosa tsamba la NPs omwe amagwiritsidwa ntchito ngati chochepetsera mu NZVI alinso ndi mawonekedwe ozungulira okhala ndi mainchesi 20 mpaka 40 nm26.
Zithunzi za TEM za Hybrid rGO/nZVI (Mku. S2C-D) zinawonetsa kuti rGO ndi ndege yoyambira yomwe ili ndi makwinya am'mphepete ndi makwinya omwe amapereka malo angapo otsegula a nZVI NPs; morphology ya lamellar iyi imatsimikiziranso kupanga bwino kwa rGO. Kuphatikiza apo, NZVI NPs ili ndi mawonekedwe ozungulira okhala ndi kukula kwa tinthu kuyambira 5.32 mpaka 27 nm ndipo amaphatikizidwa mu rGO wosanjikiza ndi kubalalitsidwa pafupifupi yunifolomu. Eucalyptus tsamba lamasamba linagwiritsidwa ntchito popanga Fe NPs/rGO; Zotsatira za TEM zidatsimikiziranso kuti makwinya mu rGO wosanjikiza amathandizira kubalalitsidwa kwa Fe NPs kuposa Fe NPs koyera ndikuwonjezera kuyambiranso kwa zophatikizika. Zotsatira zofananira zidapezedwa ndi Bagheri et al. 28 pamene gulu anali anapeka ntchito akupanga njira ndi pafupifupi chitsulo nanoparticle kukula pafupifupi 17,70 nm.
Mawonekedwe a FTIR a A. halimus, nZVI, GO, rGO, ndi rGO/nZVI kompositi akuwonetsedwa mu Mkuyu. 3 A. Kukhalapo kwa magulu ogwira ntchito pamwamba pamasamba a A. halimus amawoneka pa 3336 cm-1, omwe amafanana ndi polyphenols, ndi 1244 cm-1, omwe amafanana ndi magulu a carbonyl opangidwa ndi mapuloteni. Magulu ena monga alkanes pa 2918 cm-1, alkenes pa 1647 cm-1 ndi CO-O-CO extensions pa 1030 cm-1 awonedwanso, kutanthauza kukhalapo kwa zigawo za zomera zomwe zimagwira ntchito ngati zosindikizira ndipo zimakhala ndi udindo wobwezeretsa. kuchokera ku Fe2+ mpaka Fe0 ndi PITA ku rGO29. Nthawi zambiri, mawonekedwe a NZVI amawonetsa nsonga zofananira ngati mashuga owawa, koma ndi malo osinthika pang'ono. Gulu lamphamvu likuwoneka pa 3244 cm-1 lomwe limagwirizanitsidwa ndi OH kutambasula kugwedezeka (phenols), nsonga ya 1615 imagwirizana ndi C = C, ndipo magulu a 1546 ndi 1011 cm-1 amatuluka chifukwa cha kutambasula kwa C = O (polyphenols ndi flavonoids) , CN -magulu a onunkhira amines ndi aliphatic amines adawonedwanso pa 1310 cm-1 ndi 1190 cm-1, motero13. Gulu la FTIR la GO likuwonetsa kukhalapo kwa magulu ambiri okhala ndi okosijeni wambiri, kuphatikiza gulu lotambasula la alkoxy (CO) pa 1041 cm-1, bandi yotambasula epoxy (CO) pa 1291 cm-1, C=O kutambasula. gulu la C = C kutambasula kugwedezeka pa 1619 cm-1, gulu pa 1708 cm-1 ndi gulu lalikulu la OH gulu lotambasula kugwedezeka pa 3384 cm-1 linawonekera, zomwe zimatsimikiziridwa ndi njira yabwino ya Hummers, yomwe imatsitsimula bwino ndondomeko ya graphite. Poyerekeza rGO ndi rGO/nZVI composites ndi GO spectra, mphamvu ya magulu ena okhala ndi okosijeni, monga OH pa 3270 cm-1, imachepetsedwa kwambiri, pamene ena, monga C=O pa 1729 cm-1, ali otsika kwambiri. kuchepetsedwa. zinasowa, kusonyeza kuchotsedwa bwino kwa magulu ogwira ntchito okhala ndi okosijeni mu GO ndi A. halimus extract. Zatsopano zakuthwa nsonga za rGO pa C=C kukanikizana kumawonedwa mozungulira 1560 ndi 1405 cm-1, zomwe zimatsimikizira kutsika kwa GO kupita ku rGO. Kusiyanasiyana kuchokera ku 1043 mpaka 1015 cm-1 komanso kuchokera ku 982 mpaka 918 cm-1 kunawonedwa, mwinamwake chifukwa cha kuphatikizidwa kwa zomera31,32. Weng et al., 2018 adawonanso kuchepa kwakukulu kwamagulu ogwira ntchito okosijeni ku GO, kutsimikizira kupangidwa bwino kwa rGO ndi bioreduction, popeza masamba a eucalyptus, omwe amagwiritsidwa ntchito popanga zida zochepetsera za iron graphene oxide, zidawonetsa pafupi mawonekedwe a FTIR a gawo lazomera. magulu ogwira ntchito. 33 .
A. FTIR sipekitiramu ya gallium, nZVI, rGO, GO, composite rGO/nZVI (A). Roentgenogrammy composites rGO, GO, nZVI ndi rGO/nZVI (B).
Mapangidwe a rGO/nZVI ndi nZVI composites adatsimikiziridwa makamaka ndi mawonekedwe a X-ray diffraction (mkuyu 3B). Kuchuluka kwapamwamba kwa Fe0 kunawonedwa pa 2Ɵ 44.5 °, yofanana ndi index (110) (JCPDS no. 06-0696)11. Pamwamba kwina pa 35.1 ° ya ndege (311) imatchedwa magnetite Fe3O4, 63.2 ° ikhoza kugwirizanitsidwa ndi Miller index ya ndege (440) chifukwa cha kukhalapo kwa ϒ-FeOOH (JCPDS no. 17-0536)34. Chithunzi cha X-ray cha GO chikuwonetsa nsonga yakuthwa pa 2Ɵ 10.3 ° ndi nsonga ina pa 21.1 °, kuwonetsa kutulutsa kwathunthu kwa graphite ndikuwonetsa kukhalapo kwamagulu okhala ndi okosijeni pamtunda wa GO35. Mitundu yambiri ya rGO ndi rGO/nZVI idalemba za kuzimiririka kwa nsonga za GO komanso kupangika kwa nsonga zotakata za rGO pa 2Ɵ 22.17 ndi 24.7° pamagulu a rGO ndi rGO/nZVI, motsatana, zomwe zidatsimikizira kuchira bwino kwa GO pogwiritsa ntchito zopangira mbewu. Komabe, muzophatikiza za rGO/nZVI, nsonga zowonjezera zolumikizidwa ndi ndege ya Fe0 (110) ndi bcc Fe0 (200) zidawonedwa pa 44.9\(^\circ\) ndi 65.22\(^\circ\), motsatana. .
Kuthekera kwa zeta ndikothekera pakati pa wosanjikiza wa ionic wolumikizidwa pamwamba pa tinthu tating'onoting'ono ndi njira yamadzimadzi yomwe imatsimikizira mphamvu ya electrostatic yazinthu ndikuyesa kukhazikika kwake37. Zeta zomwe zingathe kuwunika za nZVI, GO, ndi rGO/nZVI composites zinasonyeza kukhazikika kwawo chifukwa cha kukhalapo kwa milandu yolakwika ya -20.8, -22, ndi -27.4 mV, motero, pamwamba pawo, monga momwe tawonetsera pa Chithunzi S1A- C. . Zotsatira zotere zimagwirizana ndi malipoti angapo omwe amatchula kuti mayankho omwe ali ndi tinthu tating'onoting'ono tokhala ndi zeta zochepera -25 mV nthawi zambiri amawonetsa kukhazikika kwakukulu chifukwa cha kukana kwamagetsi pakati pa tinthu tating'onoting'ono. Kuphatikiza kwa rGO ndi NZVI kumapangitsa kuti gulu lipeze zolakwa zambiri ndipo motero zimakhala zokhazikika kuposa GO kapena NZVI zokha. Chifukwa chake, chodabwitsa cha electrostatic repulsion chidzapangitsa kuti pakhale ma composites okhazikika a rGO/nZVI39. Malo oyipa a GO amalola kuti imwazike mofanana mu sing'anga yamadzi popanda agglomeration, zomwe zimapanga mikhalidwe yabwino yolumikizana ndi NZVI. Mlandu wolakwika ukhoza kulumikizidwa ndi kukhalapo kwa magulu osiyanasiyana ogwira ntchito mu chotsitsa cha vwende chowawa, chomwe chimatsimikiziranso kugwirizana pakati pa GO ndi zoyambira chitsulo ndi chotsitsa chamitengo kuti apange rGO ndi NZVI, motsatana, ndi zovuta za rGO/nZVI. Zomera zamtunduwu zimatha kukhalanso ngati ma capping agents, chifukwa zimalepheretsa kuphatikizika kwa nanoparticles zomwe zimabweretsa ndipo motero zimawonjezera kukhazikika kwawo40.
Mapangidwe oyambira ndi ma valence amitundu ya nZVI ndi rGO/nZVI adatsimikiziridwa ndi XPS (mkuyu 4). Kafukufuku wa XPS wasonyeza kuti gulu la rGO/nZVI limapangidwa makamaka ndi zinthu C, O, ndi Fe, zogwirizana ndi mapu a EDS (mkuyu 4F–H). Sipekitiramu ya C1s imakhala ndi nsonga zitatu pa 284.59 eV, 286.21 eV ndi 288.21 eV kuimira CC, CO ndi C=O, motsatira. Mawonekedwe a O1s adagawidwa m'magulu atatu, kuphatikizapo 531.17 eV, 532.97 eV, ndi 535.45 eV, omwe adapatsidwa magulu a O=CO, CO, ndi NO, motsatira. Komabe, nsonga za 710.43, 714.57 ndi 724.79 eV zimatchula Fe 2p3/2, Fe+3 ndi Fe p1/2, motsatira. Mawonekedwe a XPS a nZVI (mkuyu 4C-E) adawonetsa nsonga za maelementi C, O, ndi Fe. Pamwamba pa 284.77, 286.25, ndi 287.62 eV amatsimikizira kukhalapo kwazitsulo zachitsulo-carbon, monga momwe amatchulira CC, C-OH, ndi CO, motero. Sipekitiramu ya O1 inafanana ndi nsonga zitatu za C–O/ iron carbonate (531.19 eV), hydroxyl radical (532.4 eV) ndi O–C=O (533.47 eV). Pamwamba pa 719.6 ndi Fe0, pomwe FeOOH ikuwonetsa nsonga za 717.3 ndi 723.7 eV, kuwonjezera apo, nsonga ya 725.8 eV ikuwonetsa kukhalapo kwa Fe2O342.43.
Maphunziro a XPS a magulu a nZVI ndi rGO/nZVI, motsatana (A, B). Zithunzi zonse za nZVI C1s (C), Fe2p (D), ndi O1s (E) ndi rGO/nZVI C1s (F), Fe2p (G), O1s (H) gulu.
N2 adsorption/desorption isotherm (mkuyu 5A, B) ikuwonetsa kuti magulu a NZVI ndi rGO/nZVI ali amtundu wa II. Kuonjezera apo, malo enieni (SBET) a NZVI adawonjezeka kuchokera ku 47.4549 mpaka 152.52 m2 / g atatha khungu ndi rGO. Chotsatirachi chikhoza kufotokozedwa ndi kuchepa kwa maginito a NZVI pambuyo pa khungu la rGO, potero kuchepetsa kuphatikizika kwa tinthu ndikuwonjezera kumtunda kwa ma composite. Kuonjezera apo, monga momwe tawonetsera mkuyu 5C, voliyumu ya pore (8.94 nm) ya gulu la rGO/nZVI ndilapamwamba kuposa la NZVI (2.873 nm). Chotsatirachi chikugwirizana ndi El-Monaem et al. 45 .
Kuti muwunikire mphamvu yotsatsa kuti muchotse DC pakati pa zophatikizika za rGO/nZVI ndi NZVI yoyambirira kutengera kuchuluka kwa ndende yoyambira, kufananitsa kunapangidwa powonjezera mlingo wokhazikika wa adsorbent iliyonse (0.05 g) ku DC pazoyambira zosiyanasiyana. Yankho lofufuzidwa [25]. -100 mg l–1] pa 25°C. Zotsatira zake zidawonetsa kuti kuthekera kochotsa (94.6%) kwa gulu la rGO/nZVI kunali kokulirapo kuposa koyambirira kwa NZVI (90%) pamalo otsika (25 mg L-1). Komabe, pamene ndende yoyambira idakulitsidwa mpaka 100 mg L-1, kuchotsedwa kwa rGO/nZVI ndi NZVI ya makolo kudatsika mpaka 70% ndi 65%, motsatana (Chithunzi 6A), zomwe zitha kukhala chifukwa cha kuchepa kwa malo ogwirira ntchito komanso kuwonongeka kwa NZVI particles. M'malo mwake, rGO/nZVI idawonetsa kugwiritsa ntchito bwino kwambiri pakuchotsa DC, zomwe zitha kukhala chifukwa cha mgwirizano pakati pa rGO ndi NZVI, momwe masamba okhazikika omwe amapezeka kuti azitha kutsatsa ndi apamwamba kwambiri, komanso pankhani ya rGO/nZVI, zambiri DC imatha kutsatiridwa kuposa nZVI yosasinthika. Komanso, mu mkuyu. 6B ikuwonetsa kuti kuchuluka kwa ma adsorption a rGO/nZVI ndi NZVI composites adakwera kuchokera ku 9.4 mg/g mpaka 30 mg/g ndi 9 mg/g, motsatana, ndikuwonjezeka kwa ndende yoyambira kuchokera 25-100 mg/L. -1.1 mpaka 28.73 mg g-1. Chifukwa chake, kuchuluka kwa kuchotsera kwa DC kunali kosagwirizana ndi kuchuluka kwa DC koyambirira, komwe kudachitika chifukwa chakuchepa kwa malo ochitirapo kanthu omwe amathandizidwa ndi adsorbent iliyonse kuti adsorption ndikuchotsa DC mu yankho. Chifukwa chake, zitha kuganiziridwa kuchokera pazotsatira izi kuti zophatikizira za rGO/nZVI zili ndi luso lapamwamba la kutsatsa ndi kuchepetsa, ndipo rGO mu kapangidwe ka rGO/nZVI itha kugwiritsidwa ntchito ngati adsorbent komanso ngati chonyamulira.
Kuchotsa bwino komanso kutsatsa kwa DC kwa gulu la rGO/nZVI ndi NZVI zinali (A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, mlingo = 0.05 g], pH. pa mphamvu ya adsorption ndi DC kuchotsa bwino pa rGO/nZVI composites (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, mlingo = 0.05 g].
Yankho pH ndiye chinthu chofunikira kwambiri pakuphunzira kwa njira zotsatsira, chifukwa zimakhudza kuchuluka kwa ionization, speciation, ndi ionization ya adsorbent. Kuyesera kunachitika pa 25 ° C ndi mlingo wokhazikika wa adsorbent (0.05 g) ndi ndende yoyamba ya 50 mg L-1 mu pH range (3-11). Malinga ndi ndemanga ya mabuku46, DC ndi molekyulu ya amphiphilic yokhala ndi magulu angapo ogwira ntchito (phenols, magulu amino, mowa) pamlingo wosiyanasiyana wa pH. Zotsatira zake, ntchito zosiyanasiyana za DC ndi zida zofananira zomwe zili pamwamba pa rGO/nZVI kompositi zitha kulumikizidwa mwamagetsi ndipo zitha kukhala ngati ma cation, ma zwitterion, ndi anions, molekyulu ya DC ilipo ngati cationic (DCH3+) pa pH <3.3, zwitterionic (DCH20) 3.3 <pH <7.7 ndi anionic (DCH− kapena DC2-) pa PH 7.7. Zotsatira zake, ntchito zosiyanasiyana za DC ndi zida zofananira zomwe zili pamwamba pa rGO/nZVI kompositi zitha kulumikizidwa mwamagetsi ndipo zitha kukhala ngati ma cation, ma zwitterion, ndi anions, molekyulu ya DC ilipo ngati cationic (DCH3+) pa pH <3.3, zwitterionic (DCH20) 3.3 <pH <7.7 ndi anionic (DCH- kapena DC2-) pa PH 7.7. В результате различные функции ДК и связанных с ними структур на поверхности композита в заимодействовать электствовать электровика нов, цвиттер-ионов ndi анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер- ионный (DCH20) 3,3 < pH <7,7 ndi анионный (DCH- или DC2-) при pH 7,7. Zotsatira zake, ntchito zosiyanasiyana za DC ndi zida zofananira zomwe zili pamwamba pa rGO/nZVI kompositi zimatha kuyanjana mwamagetsi ndipo zitha kukhalapo ngati ma cation, zwitterions, ndi anions; molekyulu ya DC ilipo ngati cation (DCH3 +) pa pH <3.3; ionic (DCH20) 3.3 <pH <7.7 ndi anionic (DCH- kapena DC2-) pa pH 7.7.因此，DC 的各子子功能和rGO/nZVI 复合材料表面的相关结构可能会发生静电相互作用，并离恶、什么可能给形式存在，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 复合 材料 表面 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 в электуктур на поверхности rGO/nZVI катионов, цвиттер-ионов ndi анионов, а молекулы ДК являются катионными (ДЦГ3+) при рН < 3,3. Chifukwa chake, ntchito zosiyanasiyana za DC ndi zida zofananira zomwe zili pamwamba pa rGO/nZVI kompositi zimatha kulowa mumayendedwe amagetsi ndikukhalapo ngati ma cation, ma zwitterion, ndi anions, pomwe ma molekyulu a DC ndi cationic (DCH3+) pa 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. Imapezeka ngati zwitterion (DCH20) pa 3.3 <pH <7.7 ndi anion (DCH- kapena DC2-) pa pH 7.7.Ndi kuwonjezeka kwa pH kuchokera ku 3 mpaka 7, mphamvu ya adsorption ndi mphamvu ya kuchotsa DC inakula kuchokera ku 11.2 mg / g (56%) mpaka 17 mg / g (85%) (Mkuyu 6C). Komabe, pamene pH idakwera kufika pa 9 ndi 11, mphamvu ya adsorption ndi kuchotsa bwino kunatsika pang'ono, kuchokera ku 10.6 mg / g (53%) mpaka 6 mg / g (30%), motsatira. Ndi kuwonjezeka kwa pH kuchokera ku 3 kufika ku 7, ma DCs analipo makamaka ngati ma zwitterions, zomwe zinawapangitsa kuti asakopeke ndi magetsi kapena kunyansidwa ndi rGO/nZVI composites, makamaka ndi electrostatic interaction. Pamene pH inakwera pamwamba pa 8.2, pamwamba pa adsorbent inali yolakwika, motero mphamvu ya adsorption inachepa ndi kuchepa chifukwa cha kutengeka kwa electrostatic pakati pa doxycycline yowonongeka ndi pamwamba pa adsorbent. Izi zikusonyeza kuti kutsatsa kwa DC pamitundu ya rGO/nZVI kumadalira pH kwambiri, ndipo zotsatira zake zikuwonetsanso kuti zophatikizira za rGO/nZVI ndi zabwino ngati zotsatsa pansi pa acidic komanso kusalowerera ndale.
Zotsatira za kutentha pa kutsekemera kwa njira yamadzimadzi ya DC kunachitika pa (25-55 ° C). Chithunzi 7A chikuwonetsa momwe kutentha kumakhudzira pakuchotsa bwino kwa maantibayotiki a DC pa rGO/nZVI, zikuwonekeratu kuti mphamvu yochotsa ndi kutsatsa idakwera kuchoka pa 83.44% ndi 13.9 mg/g mpaka 47% ndi 7.83 mg/g. , motero. Kutsika kwakukulu kumeneku kungakhale chifukwa cha kuwonjezeka kwa mphamvu zotentha za DC ions, zomwe zimatsogolera ku desorption47.
Zotsatira za Kutentha pa Kuchotsa Mwachangu ndi Kuthekera kwa Adsorption ya CD pa rGO/nZVI Composites (A) [Co = 50 mg L–1, pH = 7, Mlingo = 0.05 g], Mlingo wa Adsorbent pa Kuchotsa Bwino ndi Kuchotsa Mphamvu ya CD Kuyang'ana Koyambirira pa kuchuluka kwa kutsatsa komanso kuchita bwino kwa DC kuchotsa pagulu la 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, mlingo = 0.05 g].
Zotsatira za kuonjezera mlingo wa composite adsorbent rGO/nZVI kuchokera ku 0.01 g kufika ku 0.07 g pakuchotsa bwino komanso mphamvu yotsatsa ikuwonetsedwa mkuyu. 7B . Kuwonjezeka kwa mlingo wa adsorbent kunapangitsa kuchepa kwa mphamvu ya adsorption kuchokera ku 33.43 mg / g mpaka 6.74 mg / g. Komabe, pakuwonjezeka kwa mlingo wa adsorbent kuchokera ku 0,01 g mpaka 0,07 g, kuchotsa kwachangu kumawonjezeka kuchokera ku 66,8% mpaka 96%, zomwe, motero, zikhoza kugwirizana ndi kuwonjezeka kwa chiwerengero cha malo ogwira ntchito pamtunda wa nanocomposite.
Zotsatira za ndende yoyamba pa mphamvu ya adsorption ndi kuchotsa bwino [25-100 mg L-1, 25 ° C, pH 7, mlingo 0.05 g] anaphunziridwa. Pamene ndende yoyamba idawonjezedwa kuchokera ku 25 mg L-1 mpaka 100 mg L-1, kuchuluka kwa kuchotsedwa kwa gulu la rGO/nZVI kunatsika kuchoka pa 94.6% mpaka 65% (mkuyu 7C), mwina chifukwa chosowa ntchito yomwe mukufuna. masamba. . Adsorbs ndende zazikulu za DC49. Kumbali inayi, pamene chigawo choyamba chinawonjezeka, mphamvu ya adsorption inakulanso kuchokera ku 9.4 mg / g mpaka 30 mg / g mpaka mgwirizano unafikira (mkuyu 7D). Zomwe sizingalephereke izi zimachitika chifukwa cha kuchuluka kwa mphamvu yoyendetsa galimoto ndi ndende yoyamba ya DC kuposa kukana kwa DC ion mass transfer kufika pamtunda wa 50 wa gulu la rGO/nZVI.
Nthawi yolumikizana ndi maphunziro a kinetic cholinga chake ndi kumvetsetsa nthawi yofananira ya adsorption. Choyamba, kuchuluka kwa DC komwe adalengezedwa pamphindi zoyamba za 40 za nthawi yolumikizana inali pafupifupi theka la kuchuluka kwazomwe zidagulitsidwa nthawi yonseyi (mphindi 100). Pomwe mamolekyu a DC omwe ali munjira amawombana ndikupangitsa kuti asamuke mwachangu pamwamba pa gulu la rGO/nZVI zomwe zimapangitsa kutsatsa kwakukulu. Pambuyo pa 40 min, DC adsorption inakula pang'onopang'ono ndipo pang'onopang'ono mpaka mgwirizano unafikira pambuyo pa 60 min (mkuyu 7D). Popeza kuchuluka kokwanira kumatsatiridwa mkati mwa mphindi 40 zoyambirira, padzakhala kugundana kochepa ndi mamolekyu a DC ndipo malo ochepa omwe akugwira ntchito adzakhalapo kwa mamolekyu omwe alibe adsorbed. Chifukwa chake, kuchuluka kwa kutsatsa kumatha kuchepetsedwa51.
Kuti mumvetse bwino adsorption kinetics, mizere ya pseudo yoyamba (mkuyu 8A), pseudo yachiwiri (mkuyu 8B), ndi Elovich (mkuyu 8C) zitsanzo za kinetic zinagwiritsidwa ntchito. Kuchokera pazigawo zomwe zapezedwa kuchokera ku maphunziro a kinetic (Table S1), zikuwonekeratu kuti chitsanzo cha pseudosecond ndicho chitsanzo chabwino kwambiri chofotokozera adsorption kinetics, kumene mtengo wa R2 umayikidwa pamwamba kusiyana ndi mitundu ina iwiri. Palinso kufanana pakati pa ma adsorption owerengeka (qe, cal). Dongosolo la pseudo-second ndi zoyeserera (qe, exp.) ndi umboni winanso kuti dongosolo la pseudo-second ndi chitsanzo chabwino kuposa mitundu ina. Monga momwe tawonetsera mu Table 1, zikhalidwe za α (chiwerengero choyambirira cha adsorption) ndi β (kutayika kosasintha) zimatsimikizira kuti chiwerengero cha adsorption ndi chapamwamba kuposa chiwerengero cha desorption, kusonyeza kuti DC imakonda kutsatsa bwino pamagulu a rGO/nZVI52. .
Linear adsorption kinetic plots of pseudo-second order (A), pseudo- first order (B) ndi Elovich (C) [Co = 25–100 mg l–1, pH = 7, T = 25 °C, mlingo = 0.05 g ].
Maphunziro a adsorption isotherms amathandiza kudziwa kuchuluka kwa adsorbent (RGO/nRVI composite) pamitundu yosiyanasiyana ya adsorbate (DC) ndi kutentha kwadongosolo. Kuchuluka kwa kutsatsa kwakukulu kunawerengedwa pogwiritsa ntchito Langmuir isotherm, yomwe imasonyeza kuti kutsatsa kunali kofanana ndipo kumaphatikizapo kupanga adsorbate monolayer pamwamba pa adsorbent popanda kuyanjana pakati pawo53. Mitundu ina iwiri ya isotherm yomwe imagwiritsidwa ntchito kwambiri ndi Freundlich ndi Temkin. Ngakhale kuti chitsanzo cha Freundlich sichigwiritsidwa ntchito powerengera mphamvu ya adsorption, imathandizira kumvetsetsa njira zowonongeka zowonongeka komanso kuti malo omwe ali ndi adsorbent ali ndi mphamvu zosiyana, pamene chitsanzo cha Temkin chimathandizira kumvetsetsa thupi ndi mankhwala a adsorption54.
Zithunzi 9A-C zikuwonetsa mizere yamitundu ya Langmuir, Freindlich, ndi Temkin, motsatana. Makhalidwe a R2 owerengedwa kuchokera ku Freundlich (mkuyu 9A) ndi Langmuir (mkuyu 9B) ndi kuperekedwa mu Table 2 amasonyeza kuti DC adsorption pa gulu la rGO/nZVI amatsatira Freundlich (0.996) ndi Langmuir (0.988) isotherm. zitsanzo ndi Temkin (0.985). Kuchuluka kwa adsorption (qmax), kuwerengeredwa pogwiritsa ntchito mtundu wa Langmuir isotherm, kunali 31.61 mg g-1. Kuphatikiza apo, mtengo wowerengeredwa wa dimensionless separation factor (RL) uli pakati pa 0 ndi 1 (0.097), zomwe zikuwonetsa njira yabwino yotsatsira. Kupanda kutero, kuwerengeredwa kwa Freundlich kosasintha (n = 2.756) kukuwonetsa zokonda panjira iyi yoyamwa. Malinga ndi mzere wa mzere wa isotherm ya Temkin (mkuyu 9C), kutsatsa kwa DC pagulu la rGO/nZVI ndi njira yotsatsira thupi, popeza b ndi ˂ 82 kJ mol-1 (0.408)55. Ngakhale kutsatsa kwakuthupi nthawi zambiri kumayendetsedwa ndi mphamvu zofooka za van der Waals, kutsatsa kwachindunji pamagulu a rGO/nZVI kumafuna mphamvu zochepa zotsatsa [56, 57].
Freundlich (A), Langmuir (B), ndi Temkin (C) linear adsorption isotherms [Co = 25-100 mg L-1, pH = 7, T = 25 °C, mlingo = 0.05 g]. Chiwembu cha van't Hoff equation ya DC adsorption ndi rGO/nZVI composites (D) [Co = 25–100 mg l-1, pH = 7, T = 25–55 °C ndi mlingo = 0.05 g].
Kuti muwone zotsatira za kusintha kwa kutentha kwa DC kuchotsa ku rGO/nZVI composites, magawo a thermodynamic monga kusintha kwa entropy (ΔS), kusintha kwa enthalpy (ΔH), ndi kusintha kwa mphamvu kwaulere (ΔG) anawerengedwa kuchokera ku equations. 3 ndi458.
kumene \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) - thermodynamic equilibrium constant, Ce ndi CAe - rGO mu njira, motsatana /nZVI DC kukhazikika pamtunda wofanana. R ndi RT ndi kutentha kwa gasi kosalekeza komanso kutentha kwa adsorption, motsatana. Kukonzekera ln Ke motsutsana ndi 1/T kumapereka mzere wowongoka (mkuyu 9D) pomwe ∆S ndi ∆H angadziwike.
Mtengo woipa wa ΔH umasonyeza kuti ndondomekoyi ndi yoopsa. Kumbali ina, mtengo wa ΔH uli mkati mwa njira yowonetsera thupi. Makhalidwe olakwika a ΔG mu Table 3 amasonyeza kuti kutsatsa n'kotheka komanso modzidzimutsa. Zoyipa za ΔS zikuwonetsa kuyitanitsa kwakukulu kwa mamolekyu adsorbent pamadzi amadzimadzi (Table 3).
Gome 4 limafanizira gulu la rGO/nZVI ndi ma adsorbents ena omwe adanenedwa m'maphunziro am'mbuyomu. Zikuwonekeratu kuti gulu la VGO/nCVI lili ndi mphamvu zambiri zotsatsa ndipo zitha kukhala zopatsa chiyembekezo pakuchotsa maantibayotiki a DC m'madzi. Kuphatikiza apo, kutsatsa kwa rGO/nZVI kompositi ndi njira yofulumira yokhala ndi nthawi yofananira ya 60 min. Kutsatsa kwabwino kwa zophatikizika za rGO/nZVI zitha kufotokozedwa ndi synergistic zotsatira za rGO ndi NZVI.
Zithunzi 10A, B zikuwonetsa njira zomveka zochotsera maantibayotiki a DC ndi ma complex a rGO/nZVI ndi NZVI. Malinga ndi zotsatira za kuyesa kwa pH pakuchita bwino kwa DC adsorption, ndi kuwonjezeka kwa pH kuchokera 3 mpaka 7, DC adsorption pa gulu la rGO/nZVI silinayang'anitsidwe ndi kuyanjana kwa electrostatic, popeza limagwira ntchito ngati zwitterion; choncho, kusintha kwa pH mtengo sikunakhudze ndondomeko ya adsorption. Pambuyo pake, makina a adsorption amatha kuwongoleredwa ndi machitidwe osagwirizana ndi ma electrostatic monga hydrogen bonding, hydrophobic effects, ndi π-π stacking interactions pakati pa rGO/nZVI composite ndi DC66. Ndizodziwika bwino kuti makina onunkhira onunkhira omwe ali pamwamba pa graphene wosanjikiza amafotokozedwa ndi π–π kusakanikirana kwapakatikati monga mphamvu yayikulu yoyendetsera. Chophatikizikacho ndi chinthu chosanjikiza chofanana ndi graphene chokhala ndi mayamwidwe opitilira 233 nm chifukwa cha kusintha kwa π-π*. Kutengera kupezeka kwa mphete zinayi zonunkhiritsa pama cell a DC adsorbate, tidayerekeza kuti pali njira yolumikizirana π-π-stacking pakati pa onunkhira DC (π-electron acceptor) ndi dera lomwe lili ndi ma elekitironi π. RGO pamwamba. /nZVI kompositi. Komanso, monga momwe mkuyu. 10B, maphunziro a FTIR adachitidwa kuti aphunzire momwe ma cell a rGO/nZVI amaphatikizidwira ndi DC, komanso mawonekedwe a FTIR amitundu ya rGO/nZVI pambuyo pa kutsatsa kwa DC akuwonetsedwa pazithunzi 10B. 10b . Chiwongola dzanja chatsopano chikuwoneka pa 2111 cm-1, chomwe chikugwirizana ndi kugwedezeka kwa C = C chomangira, chomwe chimasonyeza kukhalapo kwa magulu ogwira ntchito omwe ali pamwamba pa 67 rGO / nZVI. Nsonga zina zimasintha kuchoka ku 1561 kufika ku 1548 cm-1 ndi kuchoka ku 1399 kufika ku 1360 cm-1, zomwe zimatsimikiziranso kuti kuyanjana kwa π-π kumagwira ntchito yofunika kwambiri pakupanga ma graphene ndi zowononga organic68,69. Pambuyo pa DC adsorption, mphamvu yamagulu ena okhala ndi okosijeni, monga OH, idatsika mpaka 3270 cm-1, zomwe zimasonyeza kuti hydrogen bonding ndi imodzi mwa njira zowonetsera. Chifukwa chake, kutengera zotsatira, kutsatsa kwa DC pagulu la rGO/nZVI kumachitika makamaka chifukwa cha π-π ma stacking ndi ma H-bond.
Njira yolumikizirana ndi maantibayotiki a DC ndi rGO/nZVI ndi NZVI complexes (A). FTIR adsorption spectra ya DC pa rGO/nZVI ndi NZVI (B).
Kuchuluka kwa mayamwidwe a NZVI pa 3244, 1615, 1546, ndi 1011 cm-1 kudawonjezeka pambuyo pa kutsatsa kwa DC pa NZVI (mku. O magulu ku DC. Komabe, kuchuluka kwapang'onopang'ono kotereku m'magulu onse owonedwa kukuwonetsa kuti palibe kusintha kwakukulu kwa ma adsorption a phytosynthetic adsorbent (nZVI) poyerekeza ndi NZVI isanayambe kutsatsa. Malinga ndi kafukufuku wina wochotsa DC ndi nZVI71, nZVI ikakumana ndi H2O, ma elekitironi amatulutsidwa kenako H+ imagwiritsidwa ntchito kupanga haidrojeni yogwira ntchito kwambiri. Pomaliza, mankhwala ena a cationic amavomereza ma elekitironi kuchokera ku haidrojeni yogwira ntchito, zomwe zimapangitsa -C=N ndi -C=C-, zomwe zimachitika chifukwa cha kugawanika kwa mphete ya benzene.
Nthawi yotumiza: Nov-14-2022