I-methylene blue emvelweni: okwenzeka kuyo, ubuthi ezidalweni zasemanzini, namanzi angcolile ngokomongo

Kunemikhakha emibili ehlukene yezincwadi zocwaningo esebenzisa igama elithi methylene blue. Owokuqala owokulinganisa okwenzeka emvelweni: unocwaningo oluyingcosana, olunezibalo, futhi olugcwele izimo ezikhawulela iziphetho. Owesibili owokuhlanzwa: mkhulu kakhulu, uneziphetho ezizwakala ziqinisekile, futhi cishe wonke wakhelwe phezu kwezixazululo zokwenziwa ezixutshwe elabhorethri. Ukuphambanisa owesibili nowokuqala kuyiphutha eliyinhloko kulesi sihloko. Iphepha locwaningo elisusa amaphesenti angu-95 kadayi ebhodleleni lelabhorethri elengezwe udayi libonise isici sempahla ethile, hhayi izinga lokugxila kwemvelo.

Lesi sihloko sigcina le mikhakha yomibili ihlukene. Siqala ngokwenzeka kuyi-molecule emanzini, bese kuba imiphumela elinganisiwe yobuthi, bese kuba yilokho okuchazwa ngempela yizibalo zamanzi angcolile.

Okwenzeka kuyo: i-cation encibilikayo enamathela ezintweni eziqinile

I-methylene blue incibilika kalula futhi ihlala inomthwalo kagesi ophozithivu kuwo wonke amazinga e-pH ajwayelekile emvelweni. Izinqolobane zezinkomba zibala ukuncibilika okucishe kube ngu-43,600 mg/L ku-25 C, kanti ukubuyekezwa okuhlolisisayo kwe-photophysics yayo kwango-2025 kuqinisekisa ukuthi udayi utholakala kakhulu njenge-cation ye-MB cishe phakathi kwe-pH engu-3.5 no-11.5. Ngakho ukuphuma kwayo emanzini ibe umhwamuko kuncane ngokungenakunakwa. Ukubanjwa ezintweni ezithile, okuyi-sorption, kuyinqubo ebalulekile.

Ngenxa yokuthi udayi uyi-cation, ubopha ngokuqinile ezindaweni ezinomthwalo kagesi onegethivu: ubumba, inzika, udaka lokuhlanzwa kwamanzi, nempahla yezinto eziphilayo. Ucwaningo oludala lomhlabathi olucashunwe ezinkombeni lwathola ukuthi udayi ubanjwa kakhulu ezintweni eziphilayo, ku-montmorillonite, naku-kaolinite, kube yingxenye encane kuphela engakhishwa, futhi ucwaningo lokushintshana kuma-ion obumba lubonisa indlela esebenza ngayo ngokuqondile njengokushintshana kwama-cation okuncike ku-pH, kuma-ion ancintisanayo, nasekugxileni kukadayi. Isilinganiso se-Koc esivame ukucashunwa esicishe sibe ngu-8,000 sibikezela umphumela ofanayo, kodwa sithathe njengesilinganiso esicatshangelwayo sikadayi one-ion kunokuba kube yinani elingaguquki elilinganisiwe. Ubudlelwano obujwayelekile be-Koc bakhelwe izinto eziphilayo ezingenawo umthwalo kagesi futhi abuwafaneli kahle ama-ion.

Udaka olusebenzayo ekuhlanzeni amanzi lubamba udayi ngendlela efanayo, ngisho nangaphandle kokubola okubangelwa izinto eziphilayo. Ucwaningo lwamaqoqo ngodaka olomisiwe lwabika amandla okubamba e-Langmuir acishe abe ngu-256 mg kadayi ngegramu yodaka ku-pH 7, futhi ucwaningo lwakamuva ngezinto ezingama-polymer ezingaphandle kwamaseli lwafinyelela cishe ku-366 mg/g, kwatholakala ukulingana ngemizuzu. Lawo ngamandla okubamba aselebhu, hhayi amazinga okususa ezikhungweni zokuhlanzwa kwamanzi, kodwa achaza ukuthi kungani umbala kadayi unganyamalala emanzini ngokubanjwa ezintweni eziqinile kuyilapho i-molecule uqobo isasinda.

Ukukhanya kwelanga kukodwa akuyona indlela ethembekile yokuwuqeda. Ukubuyekezwa kocwaningo lokuhlanzwa kwe-methylene blue kubika ukuhlolwa okukodwa lapho kwasuswa cishe amaphesenti angu-8 kuphela ngemva kwamahora angu-10 e-photolysis engenasikhuthazi, kanye nokuhlolwa okuningana kokulawula ngokukhanya okubonakalayo lapho ukulahleka kwakukuncane ngokungenakunakwa. Unganiki udayi isikhathi esisodwa esisebenza kuzo zonke izimo sokuncipha ube yingxenye ngenxa yokukhanya kwelanga. Amandla okukhanya, i-pH, umoya-mpilo, izinto eziqinile ezilengayo emanzini, kanye nokuzivuselela kukadayi ngokukhanya konke kuyawushintsha umphumela.

Ubufakazi bokubola okubangelwa izinto eziphilayo bunendawo enkulu engenadatha. Kulesi sihloko, awukho umphumela we-OECD 301 ocacile wokuhlola ukubola okulula okubangelwa izinto eziphilayo kwe-methylene blue emsulwa otholakele. Amaphepha ocwaningo oluyisisekelo lokuhlanzwa ajwayele ukubiza udayi ngomele odayi abamelana nokubola okubangelwa izinto eziphilayo, futhi amanye amaphepha okuphepha athi awuboli kalula ngezinto eziphilayo, kodwa akukho kulokhu okungathatha indawo yedatha yokuhlola okujwayelekile. Amasiko athile amabhaktheriya nama-biofilm angawususa umbala kadayi noma awuguqule ezimweni ezenziwe zafaneleka kakhulu, ngakho isitatimende esingasekelwa sincane: uvame ukuchazwa njengomelana nokubola, futhi alikho inani eliqinisekisiwe lokuphumelela noma lokungaphumeleli ekuhlolweni okujwayelekile elitholakele. Ikhemistri yokuguquka kwawo iqinisekiswe kangcono. Ukususwa kwamaqembu e-N-methyl nge-oxidation kuhamba cishe kusuka kudayi wokuqala kudlule ku-Azure B, Azure A, Azure C, naku-thionine, kanti izimo zokuncishiswa ngamakhemikhali ziguqula udayi ube yi-leucomethylene blue engenambala. Ngakho amanzi acwebile ngemva kokuncishiswa awubufakazi bokubhujiswa. Ingxenye eyinhloko ye-phenothiazine ingahlala ingaguqukile ngemva kokunyamalala kombala.

Ubuthi ezidalweni zasemanzini: imiphumela elinganisiwe ehambisana nezimo

Ukuhlolwa okujwayelekile kobuthi be-methylene blue ezintweni eziphilayo zemvelo kuncane, futhi imiphumela yakamuva ihluka kwamanye amanani amadala ezinqolobaneni zedatha ngezilinganiso ezinkulu kakhulu. Inani ngalinye elingezansi lidinga uhlobo lwesidalwa, isikhathi, nomphumela olinganisiwe, ngoba ukususa leyo mininingwane yikho okusabalalisa ukudideka.

Umphumela wakamuva obonisa ukuzwela okukhulu kakhulu ungowesidalwa esibizwa ngokuthi izeze lamanzi. Ucwaningo lwango-2023 ngemiphumela enobuthi ku-Daphnia magna lwabika i-EC50 yokungakwazi ukunyakaza yamahora angu-48 engama-microgram angu-61.5 ngelitha (0.062 mg/L) kanye ne-LC50 yamahora angu-24 engu-0.149 mg/L, nemiphumela ekusebenzeni komzimba nasekuzalaneni emazingeni angaphezu kwama-microgram angu-4.7 ngelitha. Lelo zinga lokugcina yizinga lapho kwabonakala khona umphumela ngokwezibalo zababhali, hhayi izinga elinqunywe abalawuli lapho kungabikho mphumela khona, kodwa umyalezo uwonke ucacile: ama-cladoceran ayasabela emazingeni okugxila aphansi kakhulu kunamazinga avamile odayi owengezwa elabhorethri.

Idatha yezinhlanzi ixoxa indaba encike ezimweni. Izibungu zezinhlanzi ze-fathead minnow ezachayekwa ekuhlolweni kwesikhashana nokwesikhathi esiphakathi zanikeza amanani e-LC50 yamahora angu-96 angu-45 mg/L ku-20 C nangu-15 mg/L ku-25 C, ngamanani emiphumela yesikhathi eside ezinsuku eziyisikhombisa acishe abe ngu-2.1 mg/L ekusindeni nangu-0.6 mg/L ekukhuleni ngaphansi kokukhanya kwelabhorethri. Izinga lokushisa nokukhanya kwashintsha umphumela, okubalulekile ngoba umbala kadayi uqobo ushintsha indlela ukukhanya okungena ngayo emanzini.

Izinto eziphilayo ezikhiqiza ukudla okuyisisekelo ziwela ebangeni eliphansi lamanani edijithi eyodwa ochungechungeni olulodwa olusebenzisa indlela ye-OECD. Ukuchayeka kwamahora angu-24 kuya kwangu-96 kwanikeza amanani e-EC50 ehla esuka cishe ku-62 kuya ku-5.4 mg/L ku-Chlorella vulgaris futhi esuka cishe ku-5.8 kuya ku-1.1 mg/L ku-Spirulina platensis, okuyi-cyanobacterium kunokuba kube ulwelwe oluyisidalwa se-eukaryote. Ukuhlolwa okufushane kwebhaktheriya lasolwandle i-Vibrio harveyi kwalinganisa i-EC50 yokukhiqizwa kokukhanya kwemizuzu engu-15 ecishe ibe ngu-18 mg/L kudayi ongaboliwe, okuchaza ukusabela kwebhaktheriya kwesikhashana, hhayi ukuvinjelwa kokusebenza kodaka.

Okunye okutholakele kudinga ukunakwa okukhethekile konjiniyela bokuhlanzwa kwamanzi. Izilwanyana ezincane eziguqula i-ammonia nge-oxidation zibonise ukuzwela okuhluke kakhulu: i-archaeon i-Nitrosopumilus maritimus yalahlekelwa cishe ngamaphesenti angu-65 omsebenzi wokuguqula i-ammonia ku-0.010 mg/L, kuyilapho ibhaktheriya i-Nitrosococcus oceani yayidinga cishe u-10 mg/L ukuze ibe nomphumela ofanayo ekuhlolweni kokuqhathanisa ukuvinjelwa. Lokho kuyimiphumela ebonwe njengamaphesenti okuvinjelwa kunokuba kube amanani e-IC50, kodwa kukhomba i-nitrification njengenqubo okufanele ivikelwe kunoma imaphi amanzi akhishwayo aqukethe udayi.

Umongo wezokulawula ulinganiselwe. Akuzange kuqinisekiswe isigaba se-EU esivumelanisiwe sobungozi ezidalweni zasemanzini noma i-PNEC yomphakathi ye-ECHA eqondene ne-methylene blue; le nto iyavela kumarekhodi e-ECHA ngaphandle kokuba lelo nani elilodwa lifakwe kuyo, ngakho ungakopishi i-PNEC ephepheni lokuphepha lengxube yezincibilikisi. Njengesibonelo sezwe elithile, i-New Zealand ibeka udayi esigabeni se-Aquatic Chronic 3, H412, esiyingozi ezintweni eziphilayo zasemanzini ngemiphumela ehlala isikhathi eside. Lokhu kungumongo owusizo, hhayi ukuhlukaniswa kweYurophu.

Kungani izincwadi zocwaningo ngokungcola okuyisibonelo zingeyona idatha yokuchayeka

I-methylene blue igcwele emaphephabhukwini ocwaningo nge-adsorption ne-photocatalysis ngezizathu ezisebenzayo. Ishibhile, inombala ogqamile, kulula ukuyilandela ngezindlela ze-spectrophotometry ezisetshenziselwa izixazululo zamanzi ezihlanjululwe kakhulu, inamathela kakhulu ezintweni, futhi inomlando wokuhlolwa okusemthethweni nge-ISO 10678 yezindawo ezenza i-photocatalysis. Izincwadi zokuhlolwa nge-ISO ngokwazo zixwayisa ngokuthi i-adsorption, ubumsulwa bukadayi, i-pH, umthombo wokukhanya, nokusabalala kwama-molecule kuletha amaphutha amakhulu, iphutha lokuphindaphinda imiphumela phakathi kwamalabhorethri licishe libe ngamaphesenti angu-30. Ukuba lula ukuyisebenzisa akusho ukuthi imele izimo zangempela.

Izibalo ezijwayelekile zamanzi angcolile anodayi zenza ukudideka kube kubi nakakhulu. Ukubuyekezwa okucashunwa kakhulu kwamanzi aphuma ezindaweni zokudaya kwabika ukugxila kodaya bebonke okucishe kube ngu-10 kuya ku-250 mg/L, kodwa lokhu kuhlanganisa izinhlobo eziningi zamakhemikhali odayi futhi akufanele neze kucashunwe njengokugxila kwe-methylene blue. Izilinganiso zangempela zalo dayi othile ziphansi kakhulu. Ucwaningo lwaseNingizimu Afrika lwamanzi angcolile embonini yezindwangu lwathola cishe u-2.3 mg/L emanzini angenayo no-3.2 mg/L emanzini aphumayo ngaphambi kokuba ababhali bengeze udayi kumasampula aze afinyelele ku-30 mg/L ukuze bawahlole, futhi isampula lamanzi okuhlanza izindwangu ze-batik ePhuket laliqukethe cishe u-3.6 mg/L, okuqinisekiswe nge-spectrophotometry ne-HPLC. Lawo manani edijithi eyodwa angaphansi cishe ngokuphindwe kayishumi kwamazinga okuqala angu-30 kuya ku-50 mg/L ajwayelekile emaphepheni ocwaningo lokususa udayi.

Umthetho wokufunda lezi zincwadi zocwaningo: iphesenti lokususa elibikiwe lichaza ukusebenza ekuhlolweni kwelabhorethri kusetshenziswa into eyisibonelo ezingeni lokugxila lokuqala elishiwo. Ukuchayeka kudinga idatha yamasampula ekhomba izinhlobo zamakhemikhali ezikhona. Izinkomba ezihlobene zezindlela zokuhlaziya zichaza indlela yokugcina lowo mehluko ubonakala emiphumeleni ebikiwe.

Ukuhlanzwa: yisho umphumela olinganiswayo ngaphambi kokuthi uthi udayi ususiwe

Imikhakha emithathu yokuhlanzwa isusa udayi, futhi ngamunye unendlela yawo yokwenza impumelelo yawo ibonakale inkulu kunalokho eyikho.

I-adsorption ne-biosorption kususa udayi emanzini kuyise entweni eqinile: ikhabhoni, ubumba, impahla yezinto eziphilayo, noma udaka. Umkhawulo walokhu uwukudluliswa usuka esigabeni esisodwa uye kwesinye, hhayi ukushintshwa kwamakhemikhali. Ngaphandle kokuba into yokubamba udayi esetshenzisiwe ibhujiswe noma ilahlwe ngokuphephile, udayi usekhona. Ukukwazi ukubuyisela le nqubo emuva kubhaliwe; ucwaningo olulodwa lwe-ultrafiltration lwafinyelela ekuvinjelweni kodaya cishe okuphelele ekuqaleni nge-adsorption lwabe selubuyisa udayi ngokwehlisa i-pH ukuze uwukhulule. Ukuhlolwa okuhlukile kolwelwesi kwabonisa ukubanjwa kwehla kusuka cishe kumaphesenti angu-20 kuya cishe kumaphesenti angu-2 lapho izindawo zokunamathela sezigcwele. Amasampula okuqala ayelinganisa ukusebenza kwento ebamba udayi, hhayi kolwelwesi.

I-oxidation ibhubhisa ingxenye ekhiqiza umbala, kodwa ukulahleka kombala akukhona ukuguqulwa kube izinto ezingaphili. I-oxidation ye-Fenton yezixazululo ezingu-10 kuya ku-30 mg/L yanikeza ukususwa kukadayi okungaphezu kwamaphesenti angu-98 ngehora elilodwa ku-pH engu-2 kuya ku-3, kuyilapho isidingo samakhemikhali somoya-mpilo sehla cishe ngamaphesenti angu-81 kuphela. Ukusetshenziswa kwe-ozone kwafinyelela ekuboleni okuphelele okubonakalayo ngemizuzu engu-12 ku-pH 12, ngokuncipha kwe-COD okucishe kube ngamaphesenti angu-65. Igebe phakathi kwalawo manani amabili yilapho kutholakala khona izinto eziphakathi ze-Azure nemikhiqizo ye-oxidation engaphelele. Ukususwa kombala, ukubola, ukususwa kwe-COD, nokuguqulwa kube izinto ezingaphili kuyimiphumela emine ehlukene futhi akufanele neze kusetshenziswe njengokungathi kuyinto efanayo.

Ulwelwesi lungavimba udayi ngamazinga aphezulu lapho izixazululo ezifakwayo zilawulwa, kuhlanganise nesibonelo esisodwa se-nanofiltration elabhorethri esicishe sibe nokususwa kwamaphesenti angu-99.8 esixazululweni esifakwayo esingu-100 mg/L, kodwa lukhiqiza amanzi anodayi ogxile kakhulu asadinga ukuphathwa futhi lungase luncike ngokwengxenye ku-adsorption ekuqaleni kokusebenza. Ukuqinisekisa ukusebenza ngesilinganiso esigcwele kuyisimangalo esihlukile emiphumeleni yesixazululo esifakwayo esilawulwayo.

Emsebenzini waselabhorethri nowokuhlola ngezinga elincane, imiphumela ephathekayo icacile. Gcina imfucuza kadayi ihlukanisiwe futhi inamalebula kunokuba uthele izixazululo eziluhlaza okwesibhakabhaka ezihlanjululwe kakhulu emseleni, ucabanga ukuthi isikhungo sokuhlanzwa kwamanzi sizoyibolisa ngezinto eziphilayo; ukubanjwa odakeni kungenzeka kakhulu kuyilapho ukubhujiswa kungaqinisekisiwe. Izinyathelo ezisebenzayo zeziqukathi, ukuhlukanisa, nokulahla zichazwe kumhlahlandlela wokuphathwa kwemfucuza yaselabhorethri. Imithetho yombala wamanzi akhishwayo efana nomkhawulo waseNdiya ongu-150 PCU wamanzi angcolile embonini yezindwangu ilawula umbala obonakalayo, hhayi ukugxila kwe-methylene blue, ngakho ayikho indlela esebenza kuzo zonke izimo yokuguqula amayunithi ombala abe ngu-mg/L emanzini angcolile axubile.

Isifinyezo esithembekile singena esigabeni esisodwa. I-methylene blue ibanjwa ngokuqinile ezintweni, ibola kancane ngokukhanya ngaphandle kosizo, awukho umphumela wokuhlolwa okujwayelekile kokubola ngezinto eziphilayo otholakele, iguquka ibe izinhlobo ze-Azure noma ibe isimo esincishisiwe esingenambala kunokuba inyamalale, ilimaza ezinye izidalwa zasemanzini ngaphansi kuka-0.1 mg/L kuyilapho ezinye zibekezelela amashumi e-mg/L, itholakala emanzini ambalwa akhishwayo alinganisiwe emazingeni e-mg/L edijithi eyodwa, futhi isuswa ngokubanjwa ezintweni noma nge-oxidation kuphela lapho umphumela olinganiswayo uchazwe ngokunembile. Konke okunye kuyibhodlela lelabhorethri elengezwe udayi elisalindele isampula evela endaweni yangempela.