Ukulawulwa kweemeko zokuhlalutya kwe-COD kunyango lwamanzi amdaka
1. Into ephambili-ummeli wesampuli
Kuba iisampulu zamanzi ezibekwe esweni kucoceko lwasekhaya zingalingani ngokugqithisileyo, undoqo ekufumaneni iziphumo ezichanekileyo zokubeka iliso kwi-COD kukuba isampulu kufuneka imele. Ukufezekisa le mfuneko, la manqaku alandelayo kufuneka aqatshelwe.
1.1 Vuthulula isampuli yamanzi kakuhle
Kumlinganiselo wamanzi akrwada ① kunye namanzi acociweyo ②, ibhotile yesampuli kufuneka iplagwe ngokuqinileyo kwaye ishukunyiswe ngokucokisekileyo ngaphambi kokuba iisampulu isasaze amasuntswana kunye nezinto eziqinileyo ezinqunyanyisiweyo kwisampulu yamanzi kangangoko ukuze isampuli elinganayo kunye nommeli ifunyenwe. Amanzi. Kumanzi amdaka ③ kunye ④ athe acaca ngakumbi emva konyango, iisampulu zamanzi nazo kufuneka zishukunyiswe kakuhle phambi kokuthatha iisampulu zomlinganiselo. Xa ukulinganisa i-COD kwinani elikhulu leesampuli zamanzi amdaka asekhaya, kwafunyaniswa ukuba emva kokugungqa okwaneleyo, iziphumo zokulinganisa iisampuli zamanzi azikwazi ukuphambuka okukhulu. Ibonisa ukuba isampuli imele ngakumbi.
1.2 Thatha isampuli ngokukhawuleza emva kokushukumisa isampulu yamanzi
Ekubeni amanzi amdaka aqulethe isixa esikhulu sezinto eziqinileyo ezingalinganiyo ezimisiweyo, ukuba isampuli ayithathwanga ngokukhawuleza emva kokungcangcazela, iziseko ezimisiweyo ziya kutshona ngokukhawuleza. Uxinaniso lwesampulu yamanzi, ngokukodwa ukubunjwa kwezinto eziqinileyo ezimisiweyo, ezifunyenwe ngokusebenzisa i-pipette tip kwi-sampling kwizikhundla ezahlukeneyo phezulu, phakathi kunye nezantsi kwibhotile yesampuli iya kuba yahluke kakhulu, engakwazi ukumela imeko yangempela yogutyulo, kwaye iziphumo ezilinganisiweyo azimelanga. . Thatha isampuli ngokukhawuleza emva kokungcangcazela ngokulinganayo. Nangona amaqamu eveliswa ngenxa yokungcangcazela (amanye amaqamza aya kutshabalala ngexesha lenkqubo yokususa isampula yamanzi), umthamo wesampulu uya kuba nempazamo encinci kwisixa esipheleleyo ngenxa yobukho bamaqam ashiyekileyo, kodwa le yimpazamo yohlalutyo ebangelwa ukuncitshiswa kobuninzi obupheleleyo akunanto xa kuthelekiswa nempazamo ebangelwe kukungahambelani kokumelwa kwesampulu.
Uvavanyo lolawulo lokulinganisa iisampulu zamanzi eziye zashiywa kumaxesha ahlukeneyo emva kokungcangcazela kunye nesampulu ekhawulezileyo kunye nohlalutyo ngoko nangoko emva kokungcangcazela iisampulu zifumanise ukuba iziphumo ezilinganiswe ngowangaphambili zitenxile kakhulu kwiimeko zokwenyani zomgangatho wamanzi.
1.3 Umthamo wesampula mawungabi mncinci kakhulu
Ukuba isixa sesampulu sincinci kakhulu, amasuntswana athile abangela ukusetyenziswa kweoksijini ephezulu kumdaka, ngakumbi amanzi akrwada, akanakususwa ngenxa yokuhanjiswa okungalinganiyo, ngoko ke iziphumo ezilinganisiweyo zeCOD ziya kwahluka kakhulu kwimfuno eyiyo yeoksijini yelindle. . Isampuli efanayo yavavanywa phantsi kweemeko ezifanayo kusetyenziswa i-2.00, 10.00, 20.00, kunye ne-50.00 mL imilinganiselo yesampuli. Kwafunyaniswa ukuba iziphumo ze-COD ezilinganiswe nge-2.00 mL zamanzi akrwada okanye amanzi amdaka okugqibela ayesoloko engahambelani nowona mgangatho wamanzi, kwaye ukuqheleka kwedatha yeenkcukacha-manani nako kwakubi kakhulu; I-10.00 isetyenzisiwe, ukuqheleka kweziphumo zomlinganiselo we-20.00mL isampuli yamanzi kuye kwaphuculwa kakhulu; ukuqheleka kweziphumo zeCOD zomlinganiselo wesampulu yamanzi angama-50.00mL kuhle kakhulu.
Ke ngoko, kumanzi akrwada kunye noxinzelelo olukhulu lweCOD, indlela yokunciphisa umthamo wesampulu ayifanele isetyenziswe ngokungaboniyo ukuhlangabezana neemfuno zesixa se-potassium dichromate eyongeziweyo kunye noxinzelelo lwe-titrant kumlinganiselo. Kunoko, kufuneka kuqinisekiswe ukuba isampuli inomthamo owaneleyo wesampulu kwaye imele ngokupheleleyo. Isiseko kukulungelelanisa inani le-potassium dichromate eyongeziweyo kunye noxinzelelo lwe-titrant ukuhlangabezana neemfuno ezikhethekileyo zomgangatho wamanzi wesampuli, ukwenzela ukuba idatha elinganisiweyo iya kuchaneka.
1.4 Guqula i-pipette kwaye ulungise uphawu lwesikali
Ekubeni ubungakanani besuntswana lezinto eziqinileyo ezinqunyanyisiweyo kwiisampuli zamanzi zikhulu ngokubanzi kunobubanzi bombhobho wokuphuma we-pipette, kuhlala kunzima ukususa izinto eziqinileyo ezimisiweyo kwisampulu yamanzi xa usebenzisa i-pipette eqhelekileyo ukuhambisa iisampulu zamanzi amdaka asekhaya. Okulinganiswa ngolu hlobo kuphela lixabiso leCOD lelindle elithe lasusa ngokuyinxenye izinto eziqinileyo ezimisiweyo. Kwelinye icala, nokuba inxalenye ecikizekileyo enqunyanyisiweyo isusiwe, ngenxa yokuba izibuko ukufunxa pipette lincinane kakhulu, kuthatha ixesha elide ukugcwalisa isikali, kunye nezinto eziqinileyo eziye zashukunyiswa ngokulinganayo kugutyulo ngokuthe ngcembe zitshona. , kwaye izinto ezisusiweyo azilingani ngokugqithisileyo. , iisampulu zamanzi ezingabonisi iimeko zangempela zomgangatho wamanzi, iziphumo ezilinganiswe ngolu hlobo zibophekile ukuba zibe nephutha elikhulu. Ngoko ke, ukusebenzisa i-pipette ngomlomo ococekileyo ukufunxa iisampulu zamanzi amdaka asekhaya ukulinganisa i-COD ayikwazi ukunika iziphumo ezichanekileyo. Ngoko ke, xa ufaka iisampulu zamanzi amdaka asekhaya, ngakumbi iisampuli zamanzi kunye nenani elikhulu lamasuntswana amakhulu anqunyanyisiweyo, i-pipette kufuneka iguqulwe kancinane ukuze yandise ububanzi beepores ukwenzela ukuba izinto eziqinileyo zinqunyanyiswe ngokukhawuleza, kwaye ke umgca wesikali kufuneka ube. ilungisiwe. , ukwenza umlinganiselo ube lula ngakumbi.
2. Lungisa ugxininiso kunye nomthamo wee-reagents
Kwindlela yohlalutyo lwe-COD eqhelekileyo, ukuxinwa kwe-potassium dichromate ngokuqhelekileyo yi-0.025mol / L, imali eyongeziweyo ngexesha lokulinganisa isampuli yi-5.00mL, kunye nomthamo wesampulu ye-sewage yi-10.00mL. Xa i-COD yoxinaniso lwelindle luphezulu, indlela yokuthatha iisampulu ezincinci okanye iisampulu zokuxutywa ngokuqhelekileyo zisetyenziselwa ukuhlangabezana nemida yokulinga yale miqathango ingentla. Nangona kunjalo, u-Lian Huaneng ubonelela ngee-reagents ze-COD kwiisampulu zeendawo ezahlukeneyo. Ukugxininiswa kwezi reagents ziguqulwa, ukugxininiswa kunye nomthamo we-potassium dichromate zihlengahlengiswa, kwaye emva kwenani elikhulu leemvavanyo, zihlangabezana neemfuno zokufumanisa i-COD yazo zonke iindlela zobomi.
Ukushwankathela, xa ubeka iliso kunye nokuhlalutya umgangatho wamanzi we-COD kugutyulo lwasekhaya, eyona nto ibaluleke kakhulu yokulawula ukumela isampuli. Ukuba oku akunakuqinisekiswa, okanye nayiphi na ikhonkco echaphazela ukumelwa komgangatho wamanzi ayihoywa, iziphumo zokulinganisa kunye nokuhlalutya ziya kuba zingachanekanga. iimpazamo ezikhokelela kwizigqibo zobuchwephesha eziziimpazamo.
UkukhawulezaUkufunyanwa kwe-CODIndlela eyaphuhliswa nguLianhua ngo-1982 inokubona iziphumo zeCOD kwimizuzu engama-20. Umsebenzi ulungelelaniswa kwaye isixhobo sele sisungule i-curve, sisusa isidingo se-titration kunye nokuguqulwa, okunciphisa kakhulu iimpazamo ezibangelwa yimisebenzi. Le ndlela iye yakhokela ukutsha kwezobuchwepheshe kwintsimi yokuvavanya umgangatho wamanzi kwaye yenza igalelo elikhulu.
Ixesha lokuposa: May-11-2024
