Isihloko
Indlela ye-methylene blue yokulinganisa i-sulfide
Indlela ye-methylene blue yokuhlola i-sulfide ikala i-sulfide ngokuyiguqula ibe udayi oluhlaza okwesibhakabhaka bese ikala ukumuncwa kokukhanya okubangelwa yilowo dayi. I-methylene blue ingumkhiqizo wokusabela kwamakhemikhali othwala uphawu lokuhlaziya. Ukuthela ibhodlela le-methylene blue emanzini akukhona lokhu kuhlolwa.
Ingxenye enzima ngokuvamile ukugcina isampula limelela lokho elithathwe kukho kuze kwenzeke lokho kusabela. Ukufundwa okunembile kokumuncwa kokukhanya akukwazi ukubuyisa i-sulfide ephunyukile noma eye yathola i-oxidation ngesikhathi sokuqoqwa. Futhi akukwazi ukuhlukanisa i-hydrogen sulfide ekhululekile kwamanye amaqoqo e-sulfur akhishwa lapho kulungiswa isampula.
Yini ekhiqiza umbala oluhlaza okwesibhakabhaka?
Ku-Ndlela ye-EPA 376.2, i-sulfide isabela ne-dimethyl-p-phenylenediamine lapho kukhona i-ferric chloride, kwakheke i-methylene blue. Ama-reagent ane-asidi adala izimo zokwakheka kodayi. Ithuluzi libe selikala ukumuncwa kokukhanya yisixazululo esivelayo.
Ukusabela kungachazwa kanje:
I-sulfide + N,N-dimethyl-p-phenylenediamine + Fe(III), ezimweni ezine-asidi → i-methylene blue → ukulinganiswa kokumuncwa kokukhanya.
Lokhu kungumdwebo womqondo wokuhlaziya, akuyona i-equation yokusabela kwamakhemikhali elinganisiwe. Ukwakheka nokugxila kwama-reagent, isikhathi sokwakheka kombala, ubude begagasi, kanye nobude bendlela yokukhanya kufanele kuthathwe endleleni ekhethiwe.
Le mininingwane ayikwazi ukushintshaniswa. I-EPA 376.2 icacisa ukuthi ukulinganisa kwenziwe ku-625 nm. Inqubo ye-Hach 8131 ebhalelwe ithuluzi layo le-DR/5000 isebenzisa u-665 nm. Inani elitholakala emibhalweni yesayensi mayelana nokumuncwa kokukhanya yi-methylene blue alithathi indawo yezilungiselelo nokulinganiswa kwethuluzi okuhambisana nokuhlola okuthile.
Chaza ingxenye ye-sulfide ngaphambi kokuyiqoqa
“Ukugxila kwe-hydrogen sulfide” kungafihla izinto ezahlukene okuhloswe ukuzikala. Emanzini, i-H₂S encibilikile ne-HS⁻ kuhlobene ngokwekhemistri yama-asidi nama-base. Izilinganiso zazo zincike ezimweni, okuhlanganisa ne-pH. Ukwengeza i-asidi kusampula kushintsha lokho kusatshalaliswa; akukulondolozi njengoba bekunjalo ekuqaleni ukuze kubhekwe kamuva.
I-EPA 376.2 ihlanganisa ama-sulfide aphelele nancibilikile kumasampula athile amanzi nawemfucuza, kodwa ayiwahlanganisi ama-sulfide angancibiliki ku-asidi. Ngakho-ke, igama elithi “aphelele” embikweni osebenzisa le ndlela akufanele liqondwe njengelisho zonke izinhlanganisela eziqukethe i-sulfur ezisebhodleleni. I-sulfate iyinto ehlukile ehlaziywayo, futhi i-sulfide yensimbi engancibiliki ku-asidi ingase ingatholakali.
Ngaphambi kokuqhathanisa imiphumela evela kumalabhorethri amabili, buza ukuthi iyiphi ingxenye etholwe yinqubo ngayinye. Hlola futhi isisekelo sokubika: i-mg/L njenge-sulfur ne-mg/L njenge-H₂S kuyizindlela ezahlukene zokuchaza ubuningi. Inombolo efanayo ngaphandle kwamayunithi, ukulungiswa kwesampula, nencazelo yento ehlaziywayo okufanayo ayisho ukuvumelana kwemiphumela.
Ukuhamba komsebenzi okuvikela ukulinganisa
Sebenzisa lokhu kulandelana lapho ubuyekeza ukuhamba komsebenzi okuhlongozwayo elabhorethri. Umfanekiso osekhaveni ubonisa ukusabela kwamakhemikhali nokufundwa komphumela ngokukhanya; leli thebula lichaza izinqumo ezenziwa ngaphambi kwalokho.
| Isigaba | Okufanele kubhalwe ngaphambi kokuqhubeka | Okuvinjelwa yilowo mbhalo |
|---|---|---|
| Chaza | Isampula lamanzi, lemfucuza, noma lezinto eziphilayo; ingxenye encibilikile noma ephelele ngokwencazelo yendlela | Ukuqhathanisa izinto ezahlukene ezihlaziywayo ngaphansi kwelebula elifanayo elithi “H₂S” |
| Qoqa | Isikhathi sokuqoqwa, izinga lokushisa, ukuhlungwa, isitsha, nokuchayeka emoyeni | Ukuphatha isampula elishintshile njengamanzi okuqala |
| Zinzisa | Inqubo eqondile yokulondoloza nesikhathi sokulinda esivunyelwe | Ukucabanga ukuthi ukufakwa esiqandisini kukodwa kulondoloza wonke amasampula |
| Yenza ukusabela | Inguqulo yendlela, iqoqo lokukhiqizwa kwama-reagent, imiqulu, nesikhathi sokwakheka kombala | Ukuhlanganisa izingxenye ezingahambisani zezinqubo ezahlukene |
| Kala | Ubude begagasi, ubude bendlela yokukhanya eselini, isampula elingenayo into ehlaziywayo, izilinganiso ezijwayelekile, nokuhlanjululwa | Ukuguqula umbala ube ukugxila ngaphandle kokulinganiswa kwethuluzi okufanele |
| Buyekeza | Ukuhlolwa kokutholwa kwento ehlaziywayo, ukuvumelana kwezilinganiso eziphindwe kabili, umkhawulo wokubika, namayunithi | Ukubika inombolo yethuluzi ngaphandle kwemikhawulo yayo yokuhlaziya |
Isifinyezo se-NEMI se-Standard Methods 4500-S²⁻ D sifuna ukuthi ukungena komoya kube kuncane kakhulu nokuthi ukuhlaziya kwenziwe ngokushesha noma kusetshenziswe ukulondolozwa nge-zinc acetate okucacisiwe. Inqubo yaso yokulondoloza i-sulfide ephelele isebenzisa nezimo ezine-alkali kanye nebhodlela eligcwaliswe ngokuphelele. Lezi zidingo ziyingxenye yendlela yokuphatha isampula, hhayi nje ukuhleleka komsebenzi elabhorethri.
Ukuphazamiseka kungabangela isampula libonakale linenani eliphansi elingelona iqiniso
Leso sifinyezo se-Standard Methods siphawula ama-reagent anciphisa i-oxidation avimbela ukwakheka kombala oluhlaza okwesibhakabhaka, izinsimbi ezakha ama-sulfide angancibiliki futhi angatholakali kahle ekuhlaziyeni, kanye ne-ferrocyanide yona ngokwayo ekhiqiza umbala oluhlaza okwesibhakabhaka. Ukugxila okuphezulu kakhulu kwe-sulfide nakho kungavimbela ukusabela.
Ngakho-ke, ishubhu elinombala ophaphathekile lingachazwa ngezindlela eziningana: i-sulfide encane, ukulahleka ngaphambi kokuhlaziya, ukungatholakali kwayo ngokuphelele, noma ukuvinjelwa kokwakheka kombala. Ishubhu elinombala omnyama lingase libe nombala ophazamisayo. Umbala nokufiphala kudinga ukulungiswa komthelela wangemuva okushiwo yindlela; ukususa nje inani lesampula lamanzi elingenayo into ehlaziywayo elikhethwe ngokuthanda akwanele ngaso sonke isikhathi.
Ukuhlola okuwusizo ukwengeza inani elaziwayo le-sulfide kusampula elimele amanye bese ulidlulisa ekulungisweni okufanele. Uma ukwanda okulindelekile kungatholakali, ukwakheka kwesampula noma ukuhamba komsebenzi kudinga ukuphenywa. Izinhlinzeko zokulawula ikhwalithi ku-EPA 9030B zibonisa ukuthi kungani isampula elengezwe inani elaziwayo lento ehlaziywayo lidluliswa kuyo yonke indlela, kanye namasampula angenayo into ehlaziywayo nezilinganiso ezijwayelekile zokuqinisekisa. Ukwengeza inani elaziwayo ngaphambi nje kokufunda umphumela akukwazi ukuhlola ukulahleka okwenzeke ngaphambili.
Isibonelo sasendaweni: amanzi ashisayo anqoba inqubo ehleleke kahle
Ucwaningo lwe-USGS lwase-Yellowstone olubikwe ku-Open-File Report 2010-1192 lwaqhathanisa izinqubo ezimbili ze-methylene blue nendlela ye-electrode ekhetha ama-ion athile, kusetshenziswa amasampula alondoloziwe amanzi ashisayo avela ngaphansi komhlaba.
Imiphumela ye-electrode yayihlala iphakeme. Abacwaningi bathola ukuthi i-oxidation nokuphuma kwe-H₂S njengegesi kwakuyizinkinga kumasampula ashisayo. Ukuxuba ama-reagent ombala ngaphambi kokwengeza isampula kwanikeza imiphumela yokulinganisa ngombala ephakeme kancane, kodwa kwaletha enye inkinga: i-reagent exutshiwe yonakala ngokushesha, okwenza isikhathi sibe umthombo wokungabi nembayo. Amasampula ayisikhombisa nawo ayequkethe i-thiosulfate ekugxileni ababhali abakuhlobanisa nokulinganisa ngombala okungenzeka kunikeze amanani aphansi kunawoqobo.
Ngamanzi abo ashisayo avela ngaphansi komhlaba, ababhali bakhetha ukuzinzisa ngokushesha nge-alkali nama-antioxidant, kulandelwe ukulinganisa nge-electrode. Lokhu kuwumphumela oqondile wokukhetha indlela yamanzi ashisayo, hhayi ubufakazi bokuthi zonke izilinganiso ze-electrode zingcono kunakho konke ukuhlola okwenziwa ngokulinganisa umbala.
Khetha indlela ehambisana nombuzo
| Umbuzo wokuhlaziya | Indlela okufanele ihlolwe | Umbandela oyinhloko |
|---|---|---|
| I-sulfide engatholwa kusampula lamanzi elifanele | Ukulinganisa ngombala nge-methylene blue okubhalwe ngokucacile | Londoloza ingxenye ecacisiwe futhi ubonise ukuthi i-sulfide iyatholakala kusampula |
| I-sulfide emanzini ashisayo avela ngaphansi komhlaba | Ukuzinzisa ngokushesha kusetshenziswa ukuhamba komsebenzi kwe-electrode okuqinisekisiwe | Qinisekisa ukuqoqwa nokulondolozwa kwesampula ngokwezinga lokushisa nokwakheka kwalo |
| Ama-sulfide emfucuzweni exubile noma ezintweni eziqinile | Ukulungiswa okuqondene nengxenye ethile, njenge-EPA 9030B, kanye nendlela yayo eshiwo yokunquma inani | Ukutholwa kwama-sulfide angancibiliki ku-asidi kungase kuhlale kungaphelele; ungacabangi ukuthi ukukhishwa kuhlanganisa konke |
| I-sulfide ekhululekile uma iqhathaniswa namaqoqo e-sulfur akhululwa yi-asidi kumasampula ezinto eziphilayo | Ukubamba okukhethayo noma ukwenza isakhi esisha samakhemikhali, kulandelwe ukuhlukaniswa | Thola ukuthi yiliphi iqoqo le-sulfur elikhiqiza uphawu olukalwayo |
Lo mehluko kumasampula ezinto eziphilayo mkhulu. Ocwaningweni luka-Shen nozakwabo lwango-2011 lwaselabhorethri nolwe-plasma yamagundane, izilinganiso ze-methylene blue zazikhawulelwe umbala wangemuva, ukuzwela kwendlela, kanye ne-sulfur ekhululwa yi-asidi ngesikhathi sokulungiswa. Indlela yabo ye-monobromobimane/HPLC yahlukanisa isakhi esenziwe nge-sulfide futhi yathola ukugxila okuphansi ngaphansi kwezimo ezahlolwa. Lokhu kwakuwumsebenzi wokuqinisekisa indlela yokuhlaziya, hhayi umkhawulo wokuxilonga emtholampilo noma ubufakazi bomphumela wokwelapha.
Ukulinganiswa kwethuluzi nokuhlolwa okunamagama afanayo
Linganisa ithuluzi usebenzisa izilinganiso ezijwayelekile ze-sulfide ezichazwe yinqubo, ngaphansi kwezimo ezifanayo zokusabela nezokukhanya ezisetshenziswa kumasampula. Buyekeza imiphumela yesampula elingenayo into ehlaziywayo neyezilinganiso ezijwayelekile zokuqinisekisa ngaphambi kokuguqula ukumuncwa kokukhanya kwesampula kube inani. Ijika elihle lokulinganiswa kwethuluzi lisungula ubudlelwane balezo zilinganiso ezijwayelekile; ukutholwa kwento ehlaziywayo kusampula kuqinisekisa ukuthi lobo budlelwane buhlala busebenza yini ekwakhekeni kwesampula.
Ekugcineni, ukuhlolwa kwe-MBAS kwezinto ezisebenza ebusweni ezine-anion kusebenzisa i-methylene blue ngendlela ehlukile. Ku-EPA 425.1, udayi osuvele ukhona uhlangana nezinto ezisebenza ebusweni bese ukhishwa uyiswe esigabeni se-organic. Ukulinganisa i-sulfide ngombala kwakha udayi. Ayikho kulezi zinqubo zokuhlaziya eyisiyalelo sokuhlanza amanzi. Khomba into ehlaziywayo nokusabela kwamakhemikhali ngaphambi kokukhetha i-reagent noma ukuchaza umbala oluhlaza okwesibhakabhaka.