Ukubola kwe-methylene blue ne-photocatalysis: ukuqonda imiphumela yokususwa

Ilabhorethri ihlola izikhuthazi ezimbili zokubola kwe-methylene blue nge-photocatalysis. Isikhuthazi A sisusa amaphesenti angu-95 ombala oluhlaza okwesibhakabhaka ngehora elilodwa. Isikhuthazi B sikwazi ukususa amaphesenti angu-60 kuphela. Ithimba limemezela ukuthi u-A unqobile, likubhale embikweni, bese li-oda esinye isikhuthazi salolu hlobo. Ezinyangeni kamuva, ukuhlaziywa kwekhabhoni kuveza iqiniso: ingxenye enkulu kadayi owasuswa ngu-A yayihlezi ingashintshile ebusweni bento eqinile, kuyilapho u-B empeleni ayehlukanise ama-molecule kadayi amaningi. Ukuhlelwa kwakuphambene ngoba ithimba lalilinganise umqondo owodwa kodwa lawuqamba ngegama lomunye.

Leli phutha livamile ngoba imiqondo emine ehlukene inomphumela owodwa obonakalayo: uketshezi oluluhlaza okwesibhakabhaka luyaphaphatheka. Ukunamathela ebusweni, ukuphela kombala, ukubola, nokuguqulwa kube izinto ezingaphili ngakunye kungaveza lowo mphumela, kodwa ngakunye kusho okuhlukile ngalokho okwenzeke kudayi. I-methylene blue ingenye yezinto ezisetshenziswa ezinhlelweni zokuhlaziya nezocwaningo lwemvelo lapho udayi unendima echaziwe, futhi lapha indima yawo iwukuba yisingcolisi esiyisibonelo esisuswayo noma esiguqulwayo. Ngaphambi kokuqhathanisa izikhuthazi noma ukushicilela iphesenti lokususwa, nquma ukuthi izilinganiso zakho zingasekela muphi umphumela ngempela.

Imiphumela emine, izimangalo ezine ezihlukene

Cabanga ngalokhu njengemiqondo emine enezimiso ezihlukene zokusebenza. Ngamunye uphendula umbuzo ohlukile, futhi ngamunye udinga ubufakazi bawo.

Ukunamathela ebusweni kusho ukuthi ama-molecule kadayi ayaphuma esixazululweni ahlale entweni eqinile ngaphandle kokushintsha ngokwamakhemikhali ngempela. Isivivinyo salokhu senziwa ebumnyameni kuze kube yilapho ukumuncwa ebusweni kufinyelela ezingeni elingasakhuphuki ngempela, futhi ubufakazi obuthembekile buhlanganisa udayi obuyiswe entweni eqinile ngokuwukhulula ebusweni noma ngokuwukhipha. Isikhathi esinqunyiwe semizuzu engu-30 ebumnyameni asibona ubufakazi bokulingana kuzo zonke izinto, futhi ingxoxo yakamuva yezindlela zokuhlola ibonisa ukuthi ukweqa lesi sinyathelo kudala kanjani ukuhlelwa okungamanga kwezikhuthazi lapho ukumuncwa ebumnyameni kwehluka phakathi kwezinto.

Ukuphela kombala kusho ukulahleka kwe-chromophore ebonakalayo, ngokuvamile okulandelwa eduze kwebhande eliyinhloko lokumunca ukukhanya elicishe libe ku-664 nm. Ukunamathela ebusweni, ukusabela kokwamukela ama-electron, i-N-demethylation, nokuhlukaniswa kwe-chromophore konke kunganciphisa leso silinganiso, ngakho inani elithathwe ebudeni begagasi obubodwa alikwazi ukukhomba imbangela. Qopha izibonisi ezigcwele zokumunca ukukhanya esikhundleni senombolo eyodwa: ukugudlukela kwesiqongo ohlangothini oluluhlaza okwesibhakabhaka kuyahambisana nemikhiqizo ekhishwe amaqembu e-methyl yomndeni we-Azure. Umphumela obikwe njengokususwa kwamaphesenti angu-95 ku-664 nm kufanele ubizwe ngokuphela kombala kwamaphesenti angu-95, hhayi ukubola kwamaphesenti angu-95.

Ukubola kusho ukuthi i-molecule yokuqala ye-methylene blue iguqulwe ngokwamakhemikhali. Ubufakazi butholakala nge-chromatography: udayi ongashintshile uyanyamalala ekuhlolweni nge-HPLC noma nge-UPLC kuyilapho kuvela imikhiqizo yokuguqulwa, nayo bese iyabola, futhi kungcono uma ikhonjwa nge-LC-MS. Izinkomba eziwusizo zihlanganisa i-ion ye-molecule yokuqala eduze kuka-m/z 284 kanye nochungechunge lokukhishwa kwamaqembu e-methyl ngezinyathelo: i-Azure B eduze kuka-270, i-Azure A eduze kuka-256, i-Azure C eduze kuka-242, ne-thionine eduze kuka-228. Izinguquko zama-ion ze-LC-MS/MS eziqinisekisiwe zodayi abasemanzini zishicilelwe.

Ukuguqulwa kube izinto ezingaphili kusho ukuthi ikhabhoni yezinhlanganisela eziphilayo iguqulwe yaba yimikhiqizo yokugcina yezinhlanganisela ezingaphili, ikakhulukazi i-carbon dioxide nekhabhoni yezinhlanganisela ezingaphili, kanti i-nitrogen nesibabule kugcina kusezinhlotsheni ezifana ne-ammonium, i-nitrate, ne-sulfate. Ukuncipha kwekhabhoni ephelele yezinhlanganisela eziphilayo (TOC) kuyisilinganiso sekhabhoni esisetshenziswa njalo. Ukuncipha kwesidingo se-oksijini samakhemikhali (COD) kubonisa ukwehla kwenani lezinto ezingafakwa i-oksijini, kodwa akuyona ibhalansi yesisindo sekhabhoni futhi akufakazeli ngokwakho ukuguqulwa okuphelele kube izinto ezingaphili. Ukuhlolwa kwe-sulfate, i-nitrate, ne-ammonium nge-ion chromatography kuqinisa lesi simangalo.

Izinhlobo zezikhuthazi ezihlukene — i-titania efakwe ezinye izakhi, izinto eziyinhlanganisela, izinto ezisekelwe ekhabhonini, nokunye okufanayo — kufanele ziqhathaniswe ndawonye kuphela uma zonke zihlolwa ngemiphumela nezivivinyo zokulawula ezifanayo. Into eyinhlanganisela enamathisela udayi ngamandla iyohlala ibonakala ishesha esivivinyweni sombala, okuyisona sizathu sokuthi uhlu lokuhlola olungezansi luhlukanise ukumuncwa ebusweni nokusabela ngaphambi kokuhlela izikhuthazi.

Indlela yokusebenza kokubola kwe-methylene blue nge-photocatalysis

Umndeni wemizila owamukelwayo lapho ukuvuselelwa kwe-semiconductor kwenzeka ngempela ufingqwe ekubuyekezweni kokubola kodayi nge-photocatalysis ezintweni ezisekelwe ku-titania okucashunwa kakhulu. Ama-photon amunciwe adala ama-electron ebhandeni lokuhambisa ugesi nezikhala zama-electron ebhandeni le-valence. Lezi zikhala zenza amanzi noma i-hydroxide esebusweni ibe ama-radical e-hydroxyl ngokuyiphuca ama-electron, kuyilapho ama-electron enza i-oksijini encibilikile ibe i-superoxide. Ukusabela okulandelayo okudlula kuma-radical e-hydroperoxyl naku-hydrogen peroxide kukhiqiza amanye ama-radical e-hydroxyl. Lezi zinhlobo ze-oksijini ezisebenzayo kanye nezikhala zama-electron ngokwazo zibe sezihlasela udayi.

Ukuguqulwa kwe-methylene blue ngokuvamile kuqala nge-N-demethylation elandelanayo edlula ku-Azure B, i-Azure A, ne-Azure C iye ku-thionine, kanye nokususwa kwama-electron ku-chromophore ye-phenothiazine. Ukuhlasela okulandelayo kwama-radical kuphula izibopho phakathi kwekhabhoni nesibabule naphakathi kwekhabhoni ne-nitrogen, kuvule izindandatho ze-aromatic, bese kukhiqiza izinhlanganisela zohlobo lwe-phenol ne-aniline, ama-aldehyde, nama-carboxylic acid anesisindo esiphansi sama-molecule ngaphambi kokuba ekugcineni ziguqulwe zibe izinto ezingaphili. Ukubuyekezwa okugxile ezicini ze-methylene blue nasemizileni yokubola ngokukhanya kuchaza lo mndeni ngokuningiliziwe. Izilinganiso eziqondile zamagatsha emizila zincike esikhuthazini, ku-pH, ekutholakaleni kwe-oksijini, nasekuvezweni emisebeni, ngakho bheka lolu hlelo njengomndeni wemizila kunokulandelana okukodwa okuphoqelekile.

Izici ezimbili zesivivinyo zidinga ukunakwa ngoba zishintsha isivinini sokusabela esibonakalayo ngaphandle kokushintsha izici eziyisisekelo zesikhuthazi. I-pH ishintsha ishaji kagesi ebusweni be-titania nenani lamaqembu e-hydroxyl ebusweni, okushintsha ukunamathela kukadayi one-cation bese kushintsha isivinini esibonakalayo; qhathanisa izinto ku-pH efanayo bese uqopha amanani okuqala nawokugcina. Usawoti oncibilikile nezixazululo ezigcina i-pH izinzile kusebenza ngendlela efanayo: i-chloride, i-phosphate, i-carbonate, ne-sulfate kungahlala ezindaweni ezingaphezulu futhi kushintshe ukusabela kwama-radical. Ucwaningo olugxile kusawoti wezinhlanganisela ezingaphili ku-photocatalysis ye-titania lubhala umphumela ku-methylene blue ngokuqondile.

Ugibe lokukhanya okubonakalayo

I-titania engaguquliwe idinga ukuvuselelwa ngokukhanya okuseduze ne-UV, kodwa imibiko eminingi ibonisa ukuphela kombala we-methylene blue ngaphansi kwezibani ezikhipha ukukhanya okubonakalayo kuphela, bese ithi isikhuthazi sisebenza ngokukhanya okubonakalayo. Indlela engenzeka kakhulu iwukuvuselelwa ngudayi: udayi ovuselelwe ufaka i-electron ku-semiconductor, bese leyo electron idluliselwa ku-oksijini, kuqedwe umbala ngaphandle kokuvuselelwa kwangempela kwento eqinile ngokweqa igebe lamabhande amandla. Umsebenzi wezivivinyo ogcinwe ngu-Ohtani nozakwabo ngenkinga yokukhanya okubonakalayo wabonisa lo mphumela obangelwa indlela yokuhlola, kanti isitatimende sobubanzi be-ISO 10678 sicacisa umngcele ngokukhawulela indlela yaso yokuhlola nge-methylene blue emisebeni ye-UV nangokungafaki izimangalo zokusebenza ngokukhanya okubonakalayo.

Isivivinyo esisebenzayo silula. Phinda isivivinyo ngento yokuhlola engenambala engamunci ukukhanya okubonakalayo, bese uqhathanisa ukuncika kwesivinini ebudeni begagasi nesibonisi sokumunca ukukhanya sesikhuthazi. Uma ukusebenza kulandela ukumunca kukadayi kunokumunca kwesikhuthazi, umphumela usekela ukuvuselelwa ngudayi, hhayi i-photocatalysis yokukhanya okubonakalayo eyisici sesikhuthazi ngokwaso. Khumbula lesi sivivinyo lapho ufunda izimangalo zabathengisi ngezinhlobo zezikhuthazi ezisebenza ngokukhanya okubonakalayo.

Uhlu lokuhlola imiphumela

Sebenzisa lolu hlu ngaphambi kokuhlela izikhuthazi noma ukubhala isimangalo sokususwa. Luyithuluzi laleli khasi elingasetshenziswa ngokuphindaphindiwe: zonke izivivinyo zokubola kwe-methylene blue kufanele zihlangabezane nawo wonke amaphuzu.

1. Isivivinyo sokulawula ukunamathela ebumnyameni: udayi nesikhuthazi, ngaphandle kokukhanya, kuhlanganiswa kuze kufinyelele ezingeni elingasakhuphuki elilinganisiwe, bese kubuyiswa udayi osengxenyeni eqinile, hhayi ukucabanga ukuthi isikhathi esinqunyiwe sanele.
2. Isivivinyo sokulawula ukubola ngokukhanya kuphela: udayi nokukhanya, ngaphandle kwesikhuthazi, ukuze kulinganiswe ukuphela kombala okuqondile ngaphansi kwesibani sakho nasekuhlelweni kwemishini yakho.
3. Isampula yokuhlaziya engenalutho: isikhuthazi nokukhanya, ngaphandle kukadayi, ukuze kubonakale amasignali angemuva ku-TOC, kuma-ion, nasezibonisini zokumunca ukukhanya.
4. Izimo zokusabela ezingaguquki: uhla lokukhanya lwesibani, ukugeleza kwama-photon, izinga lokushisa, ukuxutshwa, i-oksijini encibilikile, ukuma kwesitsha sokusabela, ukugxila kukadayi ekuqaleni, inani lesikhuthazi, i-pH, nengxube esizungezile kugcinwa kufana kuzo zonke izinhlobo.
5. Ukuhlukaniswa kwento eqinile ngaphambi kokuhlolwa kokukhanya: hlunga noma usebenzise i-centrifuge ukuze ukuhlakazeka kokukhanya kungafundwa njengokumuncwa kokukhanya.
6. Izibonisi ezigcwele, hhayi ubude begagasi obubodwa: bika ukuskena ukuze ukugudluka kweziqongo namabhande amasha kuhlale kubonakala.
7. Ukuqinisekiswa nge-chromatography kwanoma yisiphi isimangalo sokubola: ukulahleka kudayi wokuqala ongashintshile kanye nemikhiqizo elandelwayo.
8. Ukubalwa kwekhabhoni kwanoma yisiphi isimangalo sokuguqulwa kube izinto ezingaphili: i-TOC enamasampula angenalutho, kanye nokuhlola ukuthi ikhabhoni ebalwe njengelahlekile ayimane ithuthele entweni eqinile.
9. Ukuhlolwa kokuphuma kwezinto esikhuthazini: susa into eqinile ngokuphelele ngesivivinyo esifana nokuhlunga kusashisa, veza uketshezi oluhlungiwe emisebeni, bese uhlaziya izinsimbi ezincibilikile; ukuqhubeka kokusabela kukhomba umnikelo wezinto ezisesixazululweni esifanayo.
10. Ukuqamba ngokwethembeka: biza umphumela we-664 nm ngokuthi ukuphela kombala, umphumela we-chromatography ngokuthi ukubola, nomphumela we-TOC ngokuthi ukuguqulwa kube izinto ezingaphili.

Ucwaningo lwakamuva lwesitsha sokusabela ngokukhanya se-UV-LED oluhlanganisa izivivinyo zokunamathela ebusweni, ukuhlukaniswa kwesikhuthazi, i-UV-vis, ne-TOC lubonisa ukuthi lezi zingqimba zihlangana kanjani esigabeni esisodwa sezindlela zokuhlola.

Isibonelo esibaliwe sebhalansi yesisindo

Ake sithi isivivinyo esingu-100 mL siqala nge-methylene blue engu-10 mg/L, ngakho isitsha sokusabela sino-1.0 mg kadayi. Ngemva kokufinyelela ekulinganeni ebumnyameni, isilinganiso sesixazululo singu-8.0 mg/L, okusho ukuthi u-0.2 mg uhlezi entweni eqinile kanti u-0.8 mg usancibilikile. Ngemva kwehora elilodwa lokuveza emisebeni, ukuhlaziywa kwesixazululo esihlungiwe nge-chromatography kuveza udayi ongashintshile ongu-2.0 mg/L (u-0.2 mg esixazululweni), ukukhululwa kukadayi ebusweni kubuyisa u-0.1 mg kadayi ongashintshile entweni eqinile, kanti i-TOC ibonisa ukuthi amaphesenti angu-40 ekhabhoni yezinhlanganisela eziphilayo yokuqala aphumile ohlelweni oluhlanganisa isixazululo nento eqinile eseyikhabhoni yezinhlanganisela ezingaphili.

Ibhalansi esekelwe kukhabhoni ithi: ikhabhoni yokuqala ilingana nekadayi wokuqala osesixazululweni, kanye nekadayi wokuqala onamathele ebusweni, kanye neyemikhiqizo ephakathi yezinhlanganisela eziphilayo, kanye nekhabhoni eguqulwe yaba eyenhlanganisela ezingaphili. Lapha amaphesenti angu-20 esisindo sokuqala sikadayi asalokhu engudayi wokuqala ongashintshile (u-0.2 mg kuzo zombili izingxenye), amaphesenti angu-40 aguqulwe aba izinto ezingaphili, kanti amaphesenti angu-40 asele ayimikhiqizo yokuguqulwa yezinhlanganisela eziphilayo (imikhiqizo ephakathi esesixazululweni noma entweni eqinile, eqinisekiswa yiziqongo zemikhiqizo). Umbiko oqondile uwukubola kukadayi wokuqala kwamaphesenti angu-80 okuhambisana nokuguqulwa kube izinto ezingaphili kwamaphesenti angu-40, hhayi amaphesenti angu-95 anoma yini. Qaphela ugibe: ukube i-TOC ibilinganiswe kuphela oketshezini olungaphezulu oluhlungiwe, izinhlanganisela eziphilayo ezinamathisele ebusweni bezizobalwa njengezibhujisiwe, zikhuphule ngokungafanele inani lokuguqulwa kube izinto ezingaphili. Linganisa ikhabhoni kuyo yonke ingxube yoketshezi nezinhlayiya eziqinile lapho kungenzeka, noma ubuyisele ekubalweni ngokucacile ingxenye eboshwe entweni eqinile.

Umthetho wokubika

Yisho umphumela onezimangalo ezibuthakathaka kakhulu osekelwa ubufakazi bakho, bese wengeza izimangalo eziqinile kuphela lapho ungqimba ngalunye lwezilinganiso luhlangabezana nezimfuneko. Umsebenzi wokubola kwe-methylene blue uthola ukwethenjwa ngendlela efanayo nezinye izindlela ezisekelwe kudayi: ngokufanisa umphumela nesici indlela esilinganisa ngempela. Umhlahlandlela ohambisana nalona wokufunda izimangalo zocwaningo olusekelwe kudayi udlulisela lokhu kuqaphela ekwakhiweni kocwaningo, kanti inqubo esebenzayo yokuhlola izimo zesivivinyo ihlanganisa imikhuba yokulinganisa imishini engasetshenziswa ngokuqondile emsebenzini wezindawo zokusabela ngokukhanya.