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Mu ntchito iyi, ma composites a rGO/nZVI adapangidwa koyamba pogwiritsa ntchito njira yosavuta komanso yosamalira chilengedwe pogwiritsa ntchito Sophora yellow leaf extract ngati chochepetsera komanso chokhazikika kuti chigwirizane ndi mfundo za "green" chemistry, monga kupanga mankhwala osavulaza kwambiri. Zida zingapo zagwiritsidwa ntchito kutsimikizira kupanga bwino kwa ma composites, monga SEM, EDX, XPS, XRD, FTIR, ndi zeta potential, zomwe zikusonyeza kupanga bwino kwa ma composites. Mphamvu yochotsera ma composites atsopano ndi nZVI yoyera pamlingo woyambira wosiyanasiyana wa doxycycline ya maantibayotiki inayerekezeredwa kuti ifufuze mphamvu yogwirizana pakati pa rGO ndi nZVI. Pansi pa mikhalidwe yochotsera ya 25mg L-1, 25°C ndi 0.05g, kuchuluka kwa ma composites a nZVI yoyera kunali 90%, pomwe kuchuluka kwa ma composites a doxycycline ndi rGO/nZVI composite kunafika pa 94.6%, kutsimikizira kuti nZVI ndi rGO. Njira yothira madzi ikugwirizana ndi dongosolo la pseudo-second ndipo ikugwirizana bwino ndi chitsanzo cha Freundlich chokhala ndi mphamvu yayikulu yothira madzi ya 31.61 mg g-1 pa 25 °C ndi pH 7. Njira yoyenera yochotsera DC yaperekedwa. Kuphatikiza apo, kugwiritsidwanso ntchito kwa rGO/nZVI composite kunali 60% pambuyo pa nthawi zisanu ndi chimodzi zotsatizana zokonzanso.
Kusowa kwa madzi ndi kuipitsidwa kwa madzi tsopano ndi chiwopsezo chachikulu ku mayiko onse. M'zaka zaposachedwapa, kuipitsidwa kwa madzi, makamaka kuipitsidwa kwa maantibayotiki, kwawonjezeka chifukwa cha kuchuluka kwa kupanga ndi kugwiritsa ntchito panthawi ya mliri wa COVID-191,2,3. Chifukwa chake, kupanga ukadaulo wogwira mtima wochotsa maantibayotiki m'madzi otayidwa ndi ntchito yofunika kwambiri.
Limodzi mwa maantibayotiki osapangidwa kuchokera ku gulu la tetracycline ndi doxycycline (DC)4,5. Zanenedwa kuti zotsalira za DC m'madzi apansi panthaka ndi pamwamba sizingasinthidwe, 20-50% yokha ndi yomwe imasinthidwa ndipo yotsalayo imatulutsidwa m'chilengedwe, zomwe zimayambitsa mavuto aakulu azachilengedwe komanso azaumoyo6.
Kukumana ndi DC pamlingo wotsika kumatha kupha tizilombo toyambitsa matenda tomwe timapanga photosynthesis m'madzi, kuopseza kufalikira kwa mabakiteriya opha tizilombo toyambitsa matenda, ndikuwonjezera kukana kwa maantibayotiki, kotero chodetsa ichi chiyenera kuchotsedwa m'madzi otayira. Kuwonongeka kwachilengedwe kwa DC m'madzi ndi njira yocheperako kwambiri. Njira za physico-chemical monga photolysis, biodegradation ndi adsorption zimatha kuwonongeka pokhapokha ngati zili zochepa komanso pamlingo wotsika kwambiri7,8. Komabe, njira yotsika mtengo kwambiri, yosavuta, yosamalira chilengedwe, yosavuta kugwiritsa ntchito komanso yothandiza kwambiri ndi adsorption9,10.
Nano zero valent iron (nZVI) ndi chinthu champhamvu kwambiri chomwe chingachotse maantibayotiki ambiri m'madzi, kuphatikizapo metronidazole, diazepam, ciprofloxacin, chloramphenicol, ndi tetracycline. Luso limeneli limachitika chifukwa cha zinthu zodabwitsa zomwe nZVI ili nazo, monga reactivity yayikulu, malo akuluakulu, ndi malo ambiri omangira akunja11. Komabe, nZVI imakonda kusonkhana m'madzi chifukwa cha mphamvu za van der Wells komanso mphamvu zamaginito zambiri, zomwe zimachepetsa mphamvu yake pochotsa zinthu zodetsa chifukwa cha kupanga zigawo za oxide zomwe zimaletsa reactivity ya nZVI10,12. Kusonkhana kwa tinthu ta nZVI kungachepe posintha malo awo ndi ma surfactants ndi ma polima kapena powaphatikiza ndi zinthu zina za nanomaterials mu mawonekedwe a composites, zomwe zatsimikizira kuti ndi njira yabwino yowongolera kukhazikika kwawo m'chilengedwe13,14.
Graphene ndi chinthu cha kaboni chokhala ndi magawo awiri chokhala ndi maatomu a kaboni osakanikirana ndi sp2 omwe amakonzedwa mu lattice ya uchi. Ili ndi malo akuluakulu pamwamba, mphamvu yayikulu yamakina, ntchito yabwino kwambiri yamagetsi, kutentha kwambiri, kuyenda mwachangu kwa ma elekitironi, komanso chonyamulira choyenera chothandizira tinthu tating'onoting'ono tating'onoting'ono pamwamba pake. Kuphatikiza kwa tinthu tating'onoting'ono tachitsulo ndi graphene kumatha kupitirira kwambiri phindu la chinthu chilichonse ndipo, chifukwa cha mphamvu zake zapamwamba zakuthupi ndi zamankhwala, kumapereka kugawa bwino kwa tinthu tating'onoting'ono kuti madzi azigwira bwino ntchito15.
Zotulutsa zomera ndi njira yabwino kwambiri yopangira mankhwala ochepetsa poizoni omwe amagwiritsidwa ntchito popanga graphene oxide (rGO) ndi nZVI chifukwa zimapezeka, zotsika mtengo, zogwira ntchito limodzi, zotetezeka ku chilengedwe, ndipo zitha kugwiritsidwa ntchito ngati zochepetsera. Monga flavonoids ndi mankhwala a phenolic, zimathandizanso kukhala wokhazikika. Chifukwa chake, Atriplex halimus L. leaf extract idagwiritsidwa ntchito ngati chokonza ndi kutseka kupanga rGO/nZVI composites mu kafukufukuyu. Atriplex halimus kuchokera ku banja la Amaranthaceae ndi chitsamba chosatha chokonda nayitrogeni chokhala ndi malo ambiri.
Malinga ndi mabuku omwe alipo, Atriplex halimus (A. halimus) idagwiritsidwa ntchito koyamba kupanga zinthu zopangidwa ndi rGO/nZVI ngati njira yopangira zinthu zosawononga chilengedwe komanso yochezeka. Chifukwa chake, cholinga cha ntchitoyi chili ndi magawo anayi: (1) kupanga zinthu zopangidwa ndi rGO/nZVI ndi zinthu zopangidwa ndi makolo a nZVI pogwiritsa ntchito A. halimus aquatic leaf extract, (2) kufotokoza zinthu zopangidwa ndi phytosynthesized pogwiritsa ntchito njira zingapo kuti zitsimikizire kuti zimapangidwa bwino, (3) kuphunzira momwe rGO ndi nZVI zimagwirizanirana potenga ndi kuchotsa zinthu zodetsa za doxycycline pansi pa magawo osiyanasiyana a reaction, kukonza momwe njira yotenga zinthu zopangidwa ndi rGO imagwirira ntchito, (3) kufufuza zinthu zopangidwa ndi rGO/nZVI m'njira zosiyanasiyana zochiritsira pambuyo pa nthawi yokonza.
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%) zinagulidwa ku Merck, USA. NaCl, KCl, CaCl2, MnCl2 ndi MgCl2 zinagulidwa ku Tianjin Comio Chemical Reagent Co., Ltd. Ma reagent onse ndi oyera kwambiri. Madzi osungunuka kawiri anagwiritsidwa ntchito kukonzekera madzi onse.
Zitsanzo zoyimira za A. halimus zasonkhanitsidwa kuchokera ku malo awo achilengedwe ku Nile Delta ndipo zafika m'mphepete mwa nyanja ya Mediterranean ku Egypt. Zomera zinasonkhanitsidwa motsatira malangizo adziko lonse ndi apadziko lonse lapansi17. Pulofesa Manal Fawzi wapeza zitsanzo za zomera malinga ndi Boulos18, ndipo Dipatimenti ya Sayansi Yachilengedwe ya Yunivesite ya Alexandria imavomereza kusonkhanitsa mitundu ya zomera zomwe zaphunziridwa kuti zigwiritsidwe ntchito pazasayansi. Zitsanzo za ma voucher zimasungidwa ku Tanta University Herbarium (TANE), ma voucher nos. 14 122–14 127, malo osungira zomera omwe amapereka mwayi wopeza zinthu zomwe zasungidwa. Kuphatikiza apo, kuti muchotse fumbi kapena dothi, dulani masamba a chomeracho m'zidutswa zazing'ono, muzimutsuka katatu ndi madzi opopera ndi madzi osungunuka, kenako muumitse pa 50°C. Chomeracho chinaphwanyidwa, 5 g ya ufa wabwino unamizidwa mu 100 ml ya madzi osungunuka ndikusakanizidwa pa 70°C kwa mphindi 20 kuti mupeze chotsitsa. Chotsitsa cha Bacillus nicotianae chomwe chinapezedwa chinasefedwa kudzera mu pepala losefera la Whatman ndipo chinasungidwa m'machubu oyera komanso oyeretsedwa pa 4°C kuti chigwiritsidwenso ntchito.
Monga momwe zasonyezedwera pa Chithunzi 1, GO idapangidwa kuchokera ku ufa wa graphite pogwiritsa ntchito njira yosinthidwa ya Hummers. 10 mg ya ufa wa GO idamwazidwa mu 50 ml ya madzi oyeretsedwa kwa mphindi 30 pansi pa sonication, kenako 0.9 g ya FeCl3 ndi 2.9 g ya NaAc zidasakanizidwa kwa mphindi 60. 20 ml ya atriplex leaf extract idawonjezedwa ku yankho losakanizidwa ndi kusakaniza ndikusiyidwa pa 80°C kwa maola 8. Chotsukira chakuda chomwe chidatulukacho chidasefedwa. Ma nanocomposites okonzedwa adatsukidwa ndi ethanol ndi madzi osungunuka kenako nkuumitsidwa mu uvuni wa vacuum pa 50°C kwa maola 12.
Zithunzi zojambulidwa komanso za digito za kapangidwe kobiriwira ka rGO/nZVI ndi nZVI complexes ndikuchotsa ma antibiotic a DC m'madzi oipitsidwa pogwiritsa ntchito Atriplex halimus extract.
Mwachidule, monga momwe zasonyezedwera pa Chithunzi 1, 10 ml ya yankho la iron chloride yokhala ndi ma ion 0.05 M Fe3+ inawonjezedwa pang'onopang'ono ku 20 ml ya yankho la tsamba lowawa kwa mphindi 60 ndikutenthedwa pang'ono ndikusakaniza, kenako yankholo linayikidwa mu centrifuge pa 14,000 rpm (Hermle, 15,000 rpm) kwa mphindi 15 kuti lipereke tinthu takuda, zomwe kenako zinatsukidwa katatu ndi ethanol ndi madzi osungunuka kenako nkuumitsa mu uvuni wa vacuum pa 60°C. usiku wonse.
Ma composites a rGO/nZVI ndi nZVI opangidwa ndi zomera adadziwika ndi ma spectroscopy owoneka ndi UV (T70/T80 series UV/Vis spectrophotometers, PG Instruments Ltd, UK) pamlingo wa 200-800 nm. Pofuna kusanthula malo ndi kufalikira kwa ma composites a rGO/nZVI ndi nZVI, TEM spectroscopy (JOEL, JEM-2100F, Japan, acceleration voltage 200 kV) idagwiritsidwa ntchito. Kuti ayese magulu ogwira ntchito omwe angagwiritsidwe ntchito mu zotulutsa za zomera zomwe zimayambitsa njira yobwezeretsa ndi kukhazikika, FT-IR spectroscopy idachitika (JASCO spectrometer pamlingo wa 4000-600 cm-1). Kuphatikiza apo, zeta potential analyzer (Zetasizer Nano ZS Malvern) idagwiritsidwa ntchito kuphunzira mphamvu ya pamwamba ya zinthu zopangidwa ndi nanomaterials. Pa kuyeza kwa X-ray diffraction ya nanomaterials ya ufa, X-ray diffractometer (X'PERT PRO, Netherlands) idagwiritsidwa ntchito, ikugwira ntchito pa current (40 mA), voltage (45 kV) mu 2θ range kuyambira 20° mpaka 80° ndi CuKa1 radiation (\(\lambda =\ ) 1.54056 Ao). Energy dispersive X-ray spectrometer (EDX) (model JEOL JSM-IT100) inali ndi udindo wophunzira kapangidwe ka elemental posonkhanitsa Al K-α monochromatic X-rays kuyambira -10 mpaka 1350 eV pa XPS, spot size 400 μm K-ALPHA (Thermo Fisher Scientific, USA) mphamvu yotumizira ya full spectrum ndi 200 eV ndipo narrow spectrum ndi 50 eV. Chitsanzo cha ufa chimakanikizidwa pa chogwirira cha chitsanzo, chomwe chimayikidwa mu vacuum chamber. Sipekitiramu ya C1 s idagwiritsidwa ntchito ngati chizindikiro pa 284.58 eV kuti idziwe mphamvu yomangirira.
Kuyesa kwa adsorption kunachitika kuti aone ngati ma nanocomposites a rGO/nZVI opangidwa amagwira ntchito pochotsa doxycycline (DC) kuchokera kumadzi. Kuyesa kwa adsorption kunachitika mu ma flasks a Erlenmeyer a 25 ml pa liwiro logwedezeka la 200 rpm pa orbital shaker (Stuart, Orbital Shaker/SSL1) pa 298 K. Mwa kusakaniza yankho la DC stock (1000 ppm) ndi madzi osungunuka. Kuti aone momwe mlingo wa rGO/nSVI umakhudzira mphamvu ya adsorption, ma nanocomposites a kulemera kosiyanasiyana (0.01–0.07 g) adawonjezedwa ku 20 ml ya yankho la DC. Kuti aphunzire kinetics ndi adsorption isotherms, 0.05 g ya adsorbent idamizidwa mu yankho lamadzi la CD ndi kuchuluka koyambirira (25–100 mg L–1). Zotsatira za pH pakuchotsa DC zidaphunziridwa pa pH (3–11) ndipo kuchuluka koyamba kwa 50 mg L-1 pa 25°C. Sinthani pH ya dongosololi powonjezera pang'ono HCl kapena NaOH solution (Crison pH meter, pH meter, pH 25). Kuphatikiza apo, mphamvu ya kutentha kwa reaction pa kuyesa kwa adsorption pamlingo wa 25-55°C idafufuzidwa. Zotsatira za mphamvu ya ionic pa njira ya adsorption zidaphunziridwa powonjezera kuchuluka kosiyanasiyana kwa NaCl (0.01–4 mol L–1) pa kuchuluka koyamba kwa DC ya 50 mg L–1, pH 3 ndi 7), 25°C, ndi mlingo wa adsorbent wa 0.05 g. Kulowetsedwa kwa DC yosalowetsedwa kunayesedwa pogwiritsa ntchito dual beam UV-Vis spectrophotometer (T70/T80 series, PG Instruments Ltd, UK) yokhala ndi ma quartz 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 kulowetsedwa kwa DC, qt, Eq. 2 (mg/g) kunayesedwa pogwiritsa ntchito equation yotsatirayi.
pomwe %R ndiye mphamvu yochotsera DC (%), Co ndiye kuchuluka koyamba kwa DC panthawi 0, ndipo C ndiye kuchuluka kwa DC panthawi t, motsatana (mg L-1).
pomwe qe ndi kuchuluka kwa DC komwe kumakhudzidwa pa unit mass ya adsorbent (mg g-1), Co ndi Ce ndi kuchuluka kwa zero time ndi pa equilibrium, motsatana (mg l-1), V ndi solution voliyumu (l), ndipo m ndi adsorption mass reagent (g).
Zithunzi za SEM (Zithunzi 2A–C) zikuwonetsa mawonekedwe a lamellar a rGO/nZVI composite yokhala ndi tinthu tating'onoting'ono ta chitsulo chozungulira chomwe chimafalikira mofanana pamwamba pake, zomwe zikusonyeza kuti nZVI NPs zimalumikizidwa bwino pamwamba pa rGO. Kuphatikiza apo, pali makwinya ena mu tsamba la rGO, zomwe zikutsimikizira kuti magulu okhala ndi mpweya amachotsedwa nthawi yomweyo ndi kubwezeretsedwa kwa A. halimus GO. Makwinya akuluakulu awa amagwira ntchito ngati malo odzaza ma NPs achitsulo mwachangu. Zithunzi za nZVI (Chithunzi 2D-F) zikuwonetsa kuti ma NPs achitsulo chozungulira anali omwazikana kwambiri ndipo sanaphatikizidwe, zomwe zimachitika chifukwa cha mtundu wa zokutira wa zigawo za zomera zomwe zimachotsedwa ku chomera. Kukula kwa tinthu tating'onoting'ono kumasiyana mkati mwa 15–26 nm. Komabe, madera ena ali ndi mawonekedwe a mesoporous okhala ndi mawonekedwe a bulges ndi mabowo, omwe angapereke mphamvu yayikulu yotsatsira nZVI, chifukwa amatha kuwonjezera kuthekera kogwira mamolekyu a DC pamwamba pa nZVI. Pamene chotsitsa cha Rosa Damascus chinagwiritsidwa ntchito popanga nZVI, ma NP omwe adapezeka anali osafanana, okhala ndi ma voids ndi mawonekedwe osiyanasiyana, zomwe zidachepetsa kugwira ntchito kwawo mu Cr(VI) adsorption ndikuwonjezera nthawi yochitapo kanthu 23. Zotsatira zake zikugwirizana ndi nZVI yopangidwa kuchokera ku masamba a oak ndi mulberry, omwe makamaka ndi tinthu tating'onoting'ono tozungulira tokhala ndi kukula kosiyanasiyana kwa nanometer popanda kuoneka bwino kwa agglomeration.
Zithunzi za SEM za rGO/nZVI (AC), nZVI (D, E) composites ndi EDX patterns za nZVI/rGO (G) ndi nZVI (H) composites.
Kapangidwe ka zinthu zoyambira za rGO/nZVI ndi nZVI zopangidwa ndi zomera zinaphunziridwa pogwiritsa ntchito EDX (Chithunzi 2G, H). Kafukufuku akusonyeza kuti nZVI imapangidwa ndi kaboni (38.29% ndi kulemera), mpweya (47.41% ndi kulemera) ndi chitsulo (11.84% ndi kulemera), koma zinthu zina monga phosphorous24 ziliponso, zomwe zingapezeke kuchokera ku zomera. Kuphatikiza apo, kuchuluka kwakukulu kwa kaboni ndi mpweya kumachitika chifukwa cha kukhalapo kwa mankhwala a phytochemicals ochokera ku zomera zomwe zili m'zitsanzo za nZVI zomwe zili pansi pa nthaka. Zinthuzi zimagawidwa mofanana pa rGO koma m'ma ratios osiyanasiyana: C (39.16 wt %), O (46.98 wt %) ndi Fe (10.99 wt %), EDX rGO/nZVI imasonyezanso kupezeka kwa zinthu zina monga S, zomwe zingagwirizane ndi zomera zomwe zimachotsedwa, zimagwiritsidwa ntchito. Chiŵerengero cha C:O chomwe chilipo panopa ndi kuchuluka kwa chitsulo mu rGO/nZVI composite pogwiritsa ntchito A. halimus ndi bwino kwambiri kuposa kugwiritsa ntchito chotsitsa cha tsamba la eucalyptus, chifukwa chimasonyeza kapangidwe ka C (23.44 wt.%), O (68.29 wt.% ) ndi Fe (8.27 wt.%). wt %) 25. Nataša et al., 2022 adanenanso za kapangidwe kofanana ka nZVI komwe kamapangidwa kuchokera ku masamba a oak ndi mulberry ndipo adatsimikiza kuti magulu a polyphenol ndi mamolekyu ena omwe ali mu chotsitsa cha tsamba ndi omwe amachititsa kuti pakhale njira yochepetsera.
Kapangidwe ka nZVI komwe kamapangidwa m'zomera (Chithunzi S2A, B) kanali kozungulira komanso kosasinthasintha pang'ono, ndi kukula kwa tinthu tating'onoting'ono ta 23.09 ± 3.54 nm, komabe ma chain aggregates adawonedwa chifukwa cha mphamvu za van der Waals ndi ferromagnetism. Kapangidwe ka tinthu tating'onoting'ono komanso kozungulira kameneka kakugwirizana bwino ndi zotsatira za SEM. Zomwezi zidapezeka ndi Abdelfatah et al. mu 2021 pamene castor bean leaf extract idagwiritsidwa ntchito popanga nZVI11. Ruelas tuberosa leaf extract NPs zomwe zimagwiritsidwa ntchito ngati reducing agent mu nZVI zilinso ndi mawonekedwe ozungulira okhala ndi mainchesi a 20 mpaka 40 nm26.
Zithunzi za Hybrid rGO/nZVI composite TEM (Chithunzi S2C-D) zasonyeza kuti rGO ndi basal plane yokhala ndi makwinya ndi makwinya omwe amapereka malo ambiri okweza nZVI NPs; mawonekedwe a lamellar awa amatsimikiziranso kuti rGO idapangidwa bwino. Kuphatikiza apo, nZVI NPs zili ndi mawonekedwe ozungulira okhala ndi kukula kwa tinthu kuyambira 5.32 mpaka 27 nm ndipo zimayikidwa mu rGO layer yokhala ndi kufalikira kofanana. Chotsitsa cha tsamba la Eucalyptus chinagwiritsidwa ntchito popanga Fe NPs/rGO; Zotsatira za TEM zidatsimikiziranso kuti makwinya mu rGO layer adakweza kufalikira kwa Fe NPs kuposa Fe NPs zoyera ndikuwonjezera reactivity ya zophatikizika. Zotsatira zofananazi zidapezeka ndi Bagheri et al. 28 pamene zophatikizika zidapangidwa pogwiritsa ntchito njira zama ultrasonic ndi kukula kwapakati pa nanoparticle yachitsulo pafupifupi 17.70 nm.
Ma FTIR spectra a A. halimus, nZVI, GO, rGO, ndi rGO/nZVI composites akuwonetsedwa mu Zithunzi 3A. Kupezeka kwa magulu ogwira ntchito pamwamba pa masamba a A. halimus kumawonekera pa 3336 cm-1, komwe kumagwirizana ndi ma polyphenols, ndi 1244 cm-1, komwe kumagwirizana ndi magulu a carbonyl opangidwa ndi puloteni. Magulu ena monga alkanes pa 2918 cm-1, alkenes pa 1647 cm-1 ndi CO-O-CO extensions pa 1030 cm-1 nawonso awonedwa, zomwe zikusonyeza kukhalapo kwa zigawo za zomera zomwe zimagwira ntchito ngati zotsekera ndipo zimayambitsa kuchira kuchokera ku Fe2+ kupita ku Fe0 ndi GO kupita ku rGO29. Kawirikawiri, ma spectra a nZVI amasonyeza nsonga zofanana za kuyamwa monga shuga wowawa, koma ndi malo osinthasintha pang'ono. Mzere wamphamvu umawonekera pa 3244 cm-1 yogwirizana ndi kugwedezeka kwa OH (ma phenols), nsonga pa 1615 ikufanana ndi C=C, ndipo mizere pa 1546 ndi 1011 cm-1 imayamba chifukwa cha kutambasuka kwa C=O (ma polyphenols ndi ma flavonoids), magulu a CN a aromatic amines ndi aliphatic amines adawonedwanso pa 1310 cm-1 ndi 1190 cm-1, motsatana13. Mtundu wa FTIR wa GO umasonyeza kukhalapo kwa magulu ambiri okhala ndi mpweya wamphamvu kwambiri, kuphatikizapo gulu lotambasula la alkoxy (CO) pa 1041 cm-1, gulu lotambasula la epoxy (CO) pa 1291 cm-1, C=O. gulu la kugwedezeka kotambasula kwa C=C pa 1619 cm-1, gulu la 1708 cm-1 ndi gulu lalikulu la kugwedezeka kotambasula kwa gulu la OH pa 3384 cm-1 linaonekera, zomwe zatsimikiziridwa ndi njira yabwino ya Hummers, yomwe imachotsa bwino njira ya graphite. Poyerekeza rGO ndi rGO/nZVI composites ndi GO spectra, mphamvu ya magulu ena okhala ndi mpweya, monga OH pa 3270 cm-1, imachepa kwambiri, pomwe ena, monga C=O pa 1729 cm-1, amachepa kwathunthu. , zomwe zikusonyeza kuti magulu ogwira ntchito okhala ndi mpweya mu GO achotsedwa bwino ndi A. halimus extract. Nsonga zatsopano zakuthwa za rGO pa C=C tension zimawonedwa pafupifupi 1560 ndi 1405 cm-1, zomwe zimatsimikizira kuchepa kwa GO kupita ku rGO. Kusiyana kwa 1043 mpaka 1015 cm-1 ndi 982 mpaka 918 cm-1 kunawonedwa, mwina chifukwa cha kuphatikizidwa kwa zinthu za zomera31,32. Weng et al., 2018 adawonanso kuchepa kwakukulu kwa magulu ogwira ntchito omwe ali ndi mpweya mu GO, kutsimikizira kupangika bwino kwa rGO mwa bioreduction, popeza zotulutsa za masamba a eucalyptus, zomwe zidagwiritsidwa ntchito popanga zinthu zochepetsedwa zachitsulo cha graphene oxide, zidawonetsa ma FTIR spectra a magulu ogwira ntchito a zigawo za zomera.33.
A. FTIR spectrum ya gallium, nZVI, rGO, GO, composite rGO/nZVI (A). Roentgenogrammy composites rGO, GO, nZVI ndi rGO/nZVI (B).
Kupangidwa kwa rGO/nZVI ndi nZVI composites kunatsimikiziridwa kwambiri ndi mapangidwe a X-ray diffraction (Chithunzi 3B). Nsonga yamphamvu kwambiri ya Fe0 inawonedwa pa 2Ɵ 44.5°, yofanana ndi index (110) (JCPDS no. 06–0696)11. Nsonga ina pa 35.1° ya ndege ya (311) imayambitsidwa ndi magnetite Fe3O4, 63.2° ikhoza kugwirizanitsidwa ndi index ya Miller ya ndege ya (440) chifukwa cha kukhalapo kwa ϒ-FeOOH (JCPDS no. 17-0536)34. Kapangidwe ka X-ray ka GO kamasonyeza nsonga yakuthwa pa 2Ɵ 10.3° ndi nsonga ina pa 21.1°, kusonyeza kuchotsedwa kwathunthu kwa graphite ndikuwonetsa kukhalapo kwa magulu okhala ndi mpweya pamwamba pa GO35. Mapangidwe a rGO ndi rGO/nZVI adalemba kutha kwa ma GO peaks odziwika bwino komanso kupangidwa kwa ma rGO peaks otakata pa 2Ɵ 22.17 ndi 24.7° a ma rGO ndi rGO/nZVI composites, motsatana, zomwe zidatsimikizira kuchira bwino kwa GO ndi zotulutsa za zomera. Komabe, mu kapangidwe ka rGO/nZVI kophatikizana, ma peaks owonjezera okhudzana ndi lattice plane ya Fe0 (110) ndi bcc Fe0 (200) adawonedwa pa 44.9\(^\circ\) ndi 65.22\(^\circ\), motsatana .
Mphamvu ya zeta ndi mphamvu yomwe ili pakati pa gawo la ionic lomwe limalumikizidwa pamwamba pa tinthu tating'onoting'ono ndi yankho lamadzi lomwe limazindikira mphamvu ya electrostatic ya chinthucho ndikuyesa kukhazikika kwake37. Kusanthula kwa mphamvu ya Zeta kwa zinthu zopangidwa ndi zomera monga nZVI, GO, ndi rGO/nZVI kunawonetsa kukhazikika kwawo chifukwa cha kukhalapo kwa ma charges oipa a -20.8, -22, ndi -27.4 mV, motsatana, pamwamba pake, monga momwe zasonyezedwera pa Chithunzi S1A-C. . Zotsatirazi zikugwirizana ndi malipoti angapo omwe amatchula kuti mayankho okhala ndi tinthu tating'onoting'ono tomwe tili ndi zeta potential values zosakwana -25 mV nthawi zambiri amawonetsa kukhazikika kwakukulu chifukwa cha kugwedezeka kwa electrostatic pakati pa tinthu tating'onoting'ono. Kuphatikiza kwa rGO ndi nZVI kumalola kuti composite ipeze ma charges ambiri oipa ndipo motero imakhala ndi kukhazikika kwakukulu kuposa GO kapena nZVI yokha. Chifukwa chake, chodabwitsa cha kugwedezeka kwa electrostatic chidzatsogolera ku kupangidwa kwa ma composites okhazikika a rGO/nZVI39. Malo olakwika a GO amalola kuti afalitsidwe mofanana m'madzi opanda agglomeration, zomwe zimapangitsa kuti zinthu zigwirizane bwino ndi nZVI. Mphamvu yoipa ikhoza kugwirizanitsidwa ndi kukhalapo kwa magulu osiyanasiyana ogwira ntchito mu chotsitsa cha vwende chowawa, zomwe zimatsimikiziranso kuyanjana pakati pa GO ndi zitsulo zoyambira ndi chotsitsa cha chomera kuti apange rGO ndi nZVI, motsatana, ndi rGO/nZVI complex. Ma compounds a zomera awa amathanso kugwira ntchito ngati zophimba, chifukwa amaletsa kusonkhana kwa tinthu tating'onoting'ono tomwe timachokera ndipo motero amawonjezera kukhazikika kwawo40.
Kapangidwe ka zinthu ndi momwe valence imagwirira ntchito m'magulu a nZVI ndi rGO/nZVI zinadziwikiratu pogwiritsa ntchito XPS (Chithunzi 4). Kafukufuku wa XPS wonse wasonyeza kuti rGO/nZVI composite imapangidwa makamaka ndi zinthu C, O, ndi Fe, mogwirizana ndi EDS mapping (Chithunzi 4F–H). C1s spectrum ili ndi ma peak atatu pa 284.59 eV, 286.21 eV ndi 288.21 eV omwe akuyimira CC, CO ndi C=O, motsatana. O1s spectrum inagawidwa m'ma peak atatu, kuphatikiza 531.17 eV, 532.97 eV, ndi 535.45 eV, omwe adaperekedwa ku magulu a O=CO, CO, ndi NO, motsatana. Komabe, ma peak pa 710.43, 714.57 ndi 724.79 eV amatanthauza Fe 2p3/2, Fe+3 ndi Fe p1/2, motsatana. Ma spectra a XPS a nZVI (Chithunzi 4C-E) adawonetsa ma peak a zinthu C, O, ndi Fe. Ma peak pa 284.77, 286.25, ndi 287.62 eV amatsimikizira kukhalapo kwa ma iron-carbon alloys, monga momwe amatchulira CC, C-OH, ndi CO, motsatana. Ma spectra a O1s adafanana ndi ma peak atatu C–O/iron carbonate (531.19 eV), hydroxyl radical (532.4 eV) ndi O–C=O (533.47 eV). Ma peak pa 719.6 amanenedwa kuti ndi a Fe0, pomwe FeOOH ikuwonetsa ma peak pa 717.3 ndi 723.7 eV, kuphatikiza apo, ma peak pa 725.8 eV akuwonetsa kukhalapo kwa Fe2O342.43.
Maphunziro a XPS a nZVI ndi rGO/nZVI composites, motsatana (A, B). Ma spectra onse a nZVI C1s (C), Fe2p (D), ndi O1s (E) ndi rGO/nZVI C1s (F), Fe2p (G), O1s (H) composites.
N2 adsorption/desorption isotherm (Chithunzi 5A, B) ikuwonetsa kuti nZVI ndi rGO/nZVI composites zili mu mtundu wachiwiri. Kuphatikiza apo, malo enieni a pamwamba (SBET) a nZVI adakwera kuchoka pa 47.4549 kufika pa 152.52 m2/g pambuyo pa blinding ndi rGO. Zotsatirazi zitha kufotokozedwa ndi kuchepa kwa mphamvu zamaginito za nZVI pambuyo pa rGO blinding, motero kuchepetsa kusonkhana kwa tinthu ndikuwonjezera malo a pamwamba pa composites. Kuphatikiza apo, monga momwe zasonyezedwera mu Chithunzi 5C, voliyumu ya pore (8.94 nm) ya rGO/nZVI composite ndi yayikulu kuposa ya nZVI yoyambirira (2.873 nm). Zotsatirazi zikugwirizana ndi El-Monaem et al. 45.
Kuti tiwone mphamvu ya adsorption yochotsera DC pakati pa rGO/nZVI composites ndi nZVI yoyambirira kutengera kuwonjezeka kwa kuchuluka koyambirira, kufananiza kunachitika powonjezera mlingo wokhazikika wa adsorbent iliyonse (0.05 g) ku DC pamlingo wosiyanasiyana woyambira. Yankho lofufuzidwa [25]. –100 mg l–1] pa 25°C. Zotsatira zake zasonyeza kuti mphamvu yochotsera (94.6%) ya rGO/nZVI composite inali yokwera kuposa ya nZVI yoyambirira (90%) pamlingo wochepa (25 mg L-1). Komabe, pamene kuchuluka koyambira kunawonjezeka kufika pa 100 mg L-1, mphamvu yochotsera ya rGO/nZVI ndi nZVI yoyambirira inatsika kufika pa 70% ndi 65%, motsatana (Chithunzi 6A), zomwe zitha kukhala chifukwa cha malo ochepa ogwira ntchito komanso kuwonongeka kwa tinthu ta nZVI. M'malo mwake, rGO/nZVI inasonyeza mphamvu yapamwamba yochotsera DC, zomwe zingakhale chifukwa cha mgwirizano pakati pa rGO ndi nZVI, momwe malo okhazikika omwe amapezeka kuti azitha kulowetsedwa amakhala okwera kwambiri, ndipo pankhani ya rGO/nZVI, DC yambiri imatha kulowetsedwa kuposa nZVI yosatha. Kuphatikiza apo, mu chithunzi 6B chikuwonetsa kuti mphamvu yolowetsedwa ya rGO/nZVI ndi nZVI composites idakwera kuchokera pa 9.4 mg/g mpaka 30 mg/g ndi 9 mg/g, motsatana, ndi kuwonjezeka kwa kuchuluka koyambirira kuchokera pa 25–100 mg/L. -1.1 mpaka 28.73 mg g-1. Chifukwa chake, kuchuluka kwa DC removal kunali kogwirizana molakwika ndi kuchuluka koyambirira kwa DC, komwe kudachitika chifukwa cha kuchuluka kochepa kwa malo ochitirapo kanthu omwe amathandizidwa ndi adsorbent iliyonse kuti ilowetse ndikuchotsa DC mu yankho. Motero, tinganene kuchokera ku zotsatirazi kuti ma composites a rGO/nZVI ali ndi mphamvu yowonjezereka yotsamira ndi kuchepetsa, ndipo rGO mu kapangidwe ka rGO/nZVI ingagwiritsidwe ntchito ngati chotsamira komanso ngati chonyamulira.
Mphamvu yochotsera ndi mphamvu ya DC yoyamwa ya rGO/nZVI ndi nZVI composite inali (A, B) [Co = 25 mg l-1–100 mg l-1, T = 25 °C, mlingo = 0.05 g], pH. pa mphamvu ya adsorption ndi mphamvu ya DC yochotsera pa rGO/nZVI composites (C) [Co = 50 mg L–1, pH = 3–11, T = 25°C, mlingo = 0.05 g].
pH ya yankho ndi chinthu chofunikira kwambiri pakuphunzira njira zokopera, chifukwa zimakhudza kuchuluka kwa ionization, speciation, ndi ionization ya adsorbent. Kuyeseraku kunachitika pa 25°C ndi mlingo wokhazikika wa adsorbent (0.05 g) ndi kuchuluka koyambirira kwa 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 a ionizable (phenols, amino groups, alcohols) pamlingo wosiyanasiyana wa pH. Zotsatira zake, ntchito zosiyanasiyana za DC ndi kapangidwe kogwirizana pamwamba pa rGO/nZVI composite zimatha kuyanjana mwamagetsi ndipo zitha kukhalapo ngati ma cations, ma zwitterion, ndi ma anions, molekyulu ya DC ilipo ngati cationic (DCH3+) pa pH <3.3, ma zwitterionic (DCH20) 3.3 < pH <7.7 ndi ma anionic (DCH− kapena DC2−) pa PH 7.7. Zotsatira zake, ntchito zosiyanasiyana za DC ndi kapangidwe kogwirizana pamwamba pa rGO/nZVI composite zimatha kuyanjana mwamagetsi ndipo zitha kukhalapo ngati ma cations, ma zwitterion, ndi ma anions, molekyulu ya DC ilipo ngati cationic (DCH3+) pa pH < 3.3, ma zwitterionic (DCH20) 3.3 < pH < 7.7 ndi ma anionic (DCH- kapena DC2-) pa PH 7.7. В результате различные функции ДК и связанных с ними структур на поверхности композита rGO/nZVI могут взаимодействовать электрововать электрововать электроство виде катионов, цвиттер-ионов and анионов, молекула ДК существует в виде катиона (DCH3+) при рН < 3,3, цвиттер-ионный (DCH20
Zotsatira za kutentha pa kuyamwa kwa madzi a DC zidachitika pa (25–55°C). Chithunzi 7A chikuwonetsa zotsatira za kuwonjezeka kwa kutentha pa mphamvu yochotsera maantibayotiki a DC pa rGO/nZVI, n'zoonekeratu kuti mphamvu yochotsera ndi mphamvu yoyamwa zidakwera kuchoka pa 83.44% ndi 13.9 mg/g mpaka 47% ndi 7.83 mg/g. motsatana. Kuchepa kwakukulu kumeneku kungakhale chifukwa cha kuwonjezeka kwa mphamvu ya kutentha ya ma DC ions, zomwe zimapangitsa kuti desorption47.
Zotsatira za Kutentha pa Kuchotsa Mphamvu ndi Kulowetsa kwa CD pa rGO/nZVI Composites (A) [Co = 50 mg L–1, pH = 7, Mlingo = 0.05 g], Mlingo wa Adsorbent pa Kuchotsa Mphamvu ndi Kuchotsa Mphamvu ya CD Zotsatira za Kukhazikika Koyamba pa mphamvu ya adsorption ndi kugwira ntchito bwino kwa DC kuchotsa pa 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, mlingo = 0.05 g].
Zotsatira za kuonjezera mlingo wa composite adsorbent rGO/nZVI kuchokera pa 0.01 g mpaka 0.07 g pa mphamvu yochotsera ndi mphamvu yolandirira zikuwonetsedwa mu Chithunzi 7B. Kuwonjezeka kwa mlingo wa adsorbent kunapangitsa kuti mphamvu yolandirira ichepe kuchoka pa 33.43 mg/g kufika pa 6.74 mg/g. Komabe, ndi kuwonjezeka kwa mlingo wa adsorbent kuchoka pa 0.01 g kufika pa 0.07 g, mphamvu yochotsera imawonjezeka kuchoka pa 66.8% kufika pa 96%, zomwe, motero, zitha kugwirizanitsidwa ndi kuwonjezeka kwa chiwerengero cha malo ogwira ntchito pamwamba pa nanocomposite.
Zotsatira za kuchuluka koyambirira pa mphamvu ya kulowetsedwa kwa madzi ndi mphamvu yochotsera [25–100 mg L-1, 25°C, pH 7, mlingo wa 0.05 g] zidaphunziridwa. Pamene kuchuluka koyambirira kudawonjezeka kuchoka pa 25 mg L-1 mpaka 100 mg L-1, kuchuluka kwa kuchotsedwa kwa rGO/nZVI composite kunachepa kuchoka pa 94.6% mpaka 65% (Chithunzi 7C), mwina chifukwa cha kusakhalapo kwa malo ofunikira ogwirira ntchito. . Amakoka kuchuluka kwakukulu kwa DC49. Kumbali ina, pamene kuchuluka koyambirira kudakwera, mphamvu ya kulowetsedwa idakweranso kuchoka pa 9.4 mg/g mpaka 30 mg/g mpaka kufika pamlingo woyenera (Chithunzi 7D). Kuchitapo kanthu kosapeŵeka kumeneku kumachitika chifukwa cha kuwonjezeka kwa mphamvu yoyendetsa ndi kuchuluka koyambirira kwa DC kwakukulu kuposa kukana kwa DC ion mass transfer kuti ifike pamwamba pa 50 ya rGO/nZVI composite.
Nthawi yokhudzana ndi madzi ndi maphunziro a kinetic cholinga chake ndi kumvetsetsa nthawi yolingana ya kulowetsedwa kwa madzi. Choyamba, kuchuluka kwa DC komwe kunalowetsedwa mkati mwa mphindi 40 zoyambirira za nthawi yolumikizana kunali pafupifupi theka la kuchuluka konse komwe kunalowetsedwa mkati mwa nthawi yonse (mphindi 100). Pamene mamolekyu a DC omwe ali mu yankho amagundana zomwe zimapangitsa kuti asunthire mofulumira pamwamba pa rGO/nZVI composite zomwe zimapangitsa kuti alowetsedwe kwambiri. Pambuyo pa mphindi 40, kulowetsedwa kwa DC kunawonjezeka pang'onopang'ono mpaka kufika pamlingo wofanana pambuyo pa mphindi 60 (Chithunzi 7D). Popeza kuchuluka koyenera kumalowetsedwa mkati mwa mphindi 40 zoyambirira, padzakhala kugundana kochepa ndi mamolekyu a DC ndipo malo ochepa ogwira ntchito adzakhalapo pamamolekyu omwe sanalowetsedwe. Chifukwa chake, kuchuluka kwa kulowetsedwa kwa madzi kumatha kuchepetsedwa51.
Kuti mumvetse bwino ma adsorption kinetics, mizere ya pseudo first order (Chithunzi 8A), pseudo second order (Chithunzi 8B), ndi Elovich (Chithunzi 8C) kinetic models zinagwiritsidwa ntchito. Kuchokera ku magawo omwe apezeka kuchokera ku maphunziro a kinetic (Table S1), zikuwonekeratu kuti pseudosecond model ndiyo chitsanzo chabwino kwambiri chofotokozera ma adsorption kinetics, komwe mtengo wa R2 umayikidwa pamwamba kuposa mitundu ina iwiri. Palinso kufanana pakati pa mphamvu zowerengera za adsorption (qe, cal). Pseudo-second order ndi ma experimental values (qe, exp.) ndi umboni wina wakuti pseudo-second order ndi chitsanzo chabwino kuposa mitundu ina. Monga momwe zasonyezedwera mu Table 1, ma values a α (chiwerengero choyamba cha adsorption) ndi β (chiwerengero chokhazikika cha desorption) amatsimikizira kuti chiŵerengero cha adsorption ndi chapamwamba kuposa chiŵerengero cha desorption, zomwe zikusonyeza kuti DC imakonda kuadsorption bwino pa rGO/nZVI52 composite. .
Ma ploti a kinetic a adsorption a 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 ma isotherm a adsorption amathandiza kudziwa mphamvu ya adsorption ya adsorbent (RGO/nRVI composite) pa kutentha kosiyanasiyana kwa adsorbate (DC) ndi kutentha kwa dongosolo. Mphamvu yayikulu ya adsorption inawerengedwa pogwiritsa ntchito Langmuir isotherm, zomwe zinasonyeza kuti adsorption inali yofanana ndipo inaphatikizapo kupangidwa kwa monolayer ya adsorbate 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 kuwerengera mphamvu ya adsorption, chimathandiza kumvetsetsa njira yosiyana ya adsorption ndipo malo obisika pa adsorbent ali ndi mphamvu zosiyana, pomwe chitsanzo cha Temkin chimathandiza kumvetsetsa mphamvu zakuthupi ndi zamakemikolo za adsorption54.
Zithunzi 9A-C zikuwonetsa mizere ya zitsanzo za Langmuir, Freindlich, ndi Temkin, motsatana. Ma R2 values owerengedwa kuchokera ku mizere ya Freundlich (Chithunzi 9A) ndi Langmuir (Chithunzi 9B) ndipo akuwonetsedwa mu Table 2 akuwonetsa kuti DC adsorption pa rGO/nZVI composite ikutsatira zitsanzo za Freundlich (0.996) ndi Langmuir (0.988) isotherm ndi Temkin (0.985). Mphamvu yayikulu yotsatsira (qmax), yowerengedwa pogwiritsa ntchito chitsanzo cha Langmuir isotherm, inali 31.61 mg g-1. Kuphatikiza apo, mtengo wowerengedwa wa dimensionless separation factor (RL) uli pakati pa 0 ndi 1 (0.097), kusonyeza njira yabwino yotsatsira. Kupanda kutero, Freundlich constant yowerengedwa (n = 2.756) ikuwonetsa zomwe zimakonda njira iyi yotsatsira. Malinga ndi chitsanzo cha mzere wa Temkin isotherm (Chithunzi 9C), kulowetsedwa kwa DC pa rGO/nZVI composite ndi njira yolowetsedwa ya physical, popeza b ndi ˂ 82 kJ mol-1 (0.408)55. Ngakhale kuti kulowetsedwa kwa physical nthawi zambiri kumachitika chifukwa cha mphamvu zofooka za van der Waals, kulowetsedwa kwa direct current pa rGO/nZVI composites kumafuna mphamvu zochepa zolowetsedwa [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]. Chithunzi 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 tiwone momwe kusintha kwa kutentha kwa reaction kumakhudzira kuchotsedwa kwa DC kuchokera ku rGO/nZVI composites, magawo a thermodynamic monga entropy change (ΔS), enthalpy change (ΔH), ndi free energy change (ΔG) adawerengedwa kuchokera ku ma equation 3 ndi 458.
kumene \({K}_{e}\)=\(\frac{{C}_{Ae}}{{C}_{e}}\) – thermodynamic equilibrium constant, Ce ndi CAe – rGO mu yankho, motsatana /nZVI DC concentrations at surface equilibrium. R ndi RT ndi gas constant ndi adsorption temperature, motsatana. Kujambula ln Ke motsutsana ndi 1/T kumapereka mzere wolunjika (Chithunzi 9D) womwe ∆S ndi ∆H zitha kudziwika.
Mtengo woipa wa ΔH umasonyeza kuti njirayi ndi ya exothermic. Kumbali ina, mtengo wa ΔH uli mkati mwa njira yodziwira thupi. Mtengo woipa wa ΔG mu Table 3 umasonyeza kuti kudziwira ndi kotheka komanso mwachibadwa. Mtengo woipa wa ΔS umasonyeza kulinganiza kwakukulu kwa mamolekyu amadzimadzi pamalo olumikizirana ndi madzi (Table 3).
Gome 4 likuyerekeza rGO/nZVI composite ndi ma adsorbents ena omwe adanenedwa m'maphunziro am'mbuyomu. N'zoonekeratu kuti VGO/nCVI composite ili ndi mphamvu yayikulu yotsatsira madzi ndipo ikhoza kukhala chinthu chabwino chochotsera maantibayotiki a DC m'madzi. Kuphatikiza apo, kutsatsira kwa ma rGO/nZVI composites ndi njira yachangu yokhala ndi nthawi yolinganiza ya mphindi 60. Makhalidwe abwino kwambiri a kutsatsira kwa ma rGO/nZVI composites amatha kufotokozedwa ndi mphamvu ya rGO ndi nZVI yogwirizana.
Zithunzi 10A, B zikuwonetsa njira yolondola yochotsera maantibayotiki a DC pogwiritsa ntchito ma rGO/nZVI ndi ma nZVI complexes. Malinga ndi zotsatira za zoyeserera pa zotsatira za pH pakugwira ntchito bwino kwa DC adsorption, ndi kuwonjezeka kwa pH kuchokera pa 3 mpaka 7, DC adsorption pa rGO/nZVI composite sinalamuliridwe ndi kuyanjana kwa electrostatic, popeza imagwira ntchito ngati zwitterion; chifukwa chake, kusintha kwa pH sikunakhudze njira yolumikizira. Pambuyo pake, njira yolumikizira imatha kulamulidwa ndi kuyanjana kosakhala kwa electrostatic monga hydrogen bonding, hydrophobic effects, ndi kuyanjana kwa π-π stacking pakati pa rGO/nZVI composite ndi DC66. Ndizodziwika bwino kuti njira ya aromatic adsorbates pamwamba pa graphene yoyikidwa yafotokozedwa ndi kuyanjana kwa π-π stacking ngati mphamvu yayikulu yoyendetsera. Composite ndi zinthu zokhala ndi zigawo zofanana ndi graphene zokhala ndi mayamwidwe apamwamba pa 233 nm chifukwa cha kusintha kwa π-π*. Kutengera kukhalapo kwa mphete zinayi za aromatic mu kapangidwe ka molekyulu ya DC adsorbate, tinaganiza kuti pali njira yolumikizirana kwa π-π pakati pa aromatic DC (π-electron acceptor) ndi dera lomwe lili ndi ma π-electron ambiri pamwamba pa RGO. /nZVI composites. Kuphatikiza apo, monga momwe zasonyezedwera pachithunzi 10B, maphunziro a FTIR adachitika kuti aphunzire momwe ma molekyulu amagwirira ntchito ma rGO/nZVI composites ndi DC, ndipo ma FTIR spectra a rGO/nZVI composites pambuyo pa DC adsorption akuwonetsedwa pachithunzi 10B. 10b. Nsonga yatsopano ikuwoneka pa 2111 cm-1, yomwe ikugwirizana ndi kugwedezeka kwa chimango cha C=C bond, komwe kumasonyeza kukhalapo kwa magulu ogwira ntchito achilengedwe ogwirizana pamwamba pa 67 rGO/nZVI. Ma peak ena amasanduka kuchokera pa 1561 kufika pa 1548 cm-1 ndipo kuchokera pa 1399 kufika pa 1360 cm-1, zomwe zimatsimikiziranso kuti kuyanjana kwa π-π kumachita gawo lofunika kwambiri pakuyamwa kwa graphene ndi zonyansa za organic68,69. Pambuyo pa kuyamwa kwa DC, mphamvu ya magulu ena okhala ndi mpweya, monga OH, inachepa kufika pa 3270 cm-1, zomwe zikusonyeza kuti hydrogen bonding ndi imodzi mwa njira zoyamwa. Chifukwa chake, kutengera zotsatira zake, kuyamwa kwa DC pa rGO/nZVI composite kumachitika makamaka chifukwa cha kuyanjana kwa π-π stacking ndi H-bonds.
Njira yomveka bwino yopezera maantibayotiki a DC pogwiritsa ntchito rGO/nZVI ndi nZVI complexes (A). Ma spectra a FTIR adsorption a DC pa rGO/nZVI ndi nZVI (B).
Mphamvu ya ma absorption bands a nZVI pa 3244, 1615, 1546, ndi 1011 cm–1 inawonjezeka pambuyo pa DC adsorption pa nZVI (Chithunzi 10B) poyerekeza ndi nZVI, zomwe ziyenera kugwirizana ndi kuyanjana ndi magulu ogwira ntchito omwe angakhalepo a magulu a carboxylic acid O mu DC. Komabe, kuchuluka kochepa kwa kufalikira kwa ma bands onse omwe awonedwa sikukuwonetsa kusintha kwakukulu pakugwira ntchito kwa adsorption kwa phytosynthetic adsorbent (nZVI) poyerekeza ndi nZVI isanayambe njira yobsorption. Malinga ndi kafukufuku wina wochotsa DC ndi nZVI71, nZVI ikachitapo kanthu ndi H2O, ma elekitironi amatulutsidwa kenako H+ imagwiritsidwa ntchito kupanga active hydrogen yochepetsedwa kwambiri. Pomaliza, ma cationic compounds ena amalandira ma elekitironi kuchokera ku active hydrogen, zomwe zimapangitsa -C=N ndi -C=C-, zomwe zimachitika chifukwa cha kugawanika kwa benzene ring.
Nthawi yotumizira: Novembala-14-2022