Kudiwa kwemakemikari okisijeni kunonzi zvakare kudiwa kwemakemikari okisijeni (makemikari okisijeni inoda), inonzi COD. Iko kushandiswa kwemakemikari oxidants (akadai se potassium permanganate) kuita oxidize uye kuora zvinhu zvinogoneka mumvura (senge organic matter, nitrite, ferrous salt, sulfide, etc.), wozoverenga mashandisirwo eokisijeni zvichienderana nehuwandu hwezvasara. oxidant. Kufanana ne biochemical oxygen kudiwa (BOD), chiratidzo chakakosha chekusvibiswa kwemvura. Iyo unit yeCOD ndeye ppm kana mg/L. Iyo idiki kukosha, iyo inoreruka kusvibiswa kwemvura.
Zvinhu zvinoderedza mumvura zvinosanganisira zvinhu zvakasiyana-siyana zvehupenyu, nitrite, sulfide, ferrous salt, etc. Asi chikuru ivhu. Naizvozvo, kemikari yeokisijeni inoda (COD) inowanzo shandiswa sechiratidzo chekuyera huwandu hwezvinhu zvipenyu mumvura. Kukura kwemakemikari okisijeni, ndiko kunyanya kusvibiswa kwemvura neorganic matter. Kutemerwa kwemakemikari okisijeni kudiwa (COD) kunosiyana nekutemerwa kwekudzikisa zvinhu mumasampuli emvura uye nzira yekusimbisa. Nzira dzinonyanya kushandiswa pari zvino iacidic potassium permanganate oxidation nzira uye potassium dichromate oxidation nzira. Iyo potassium permanganate (KMnO4) nzira ine yakaderera oxidation mwero, asi iri nyore. Inogona kushandiswa kuona kukosha kwekuenzanisa kweiyo organic zvirimo mumasampuli emvura uye yakachena pamusoro pemvura uye pasi pevhu. Iyo potassium dichromate (K2Cr2O7) nzira ine yakakwira oxidation mwero uye yakanaka kuberekana. Inokodzera kutarisisa huwandu hwese hwezvinhu zvakasikwa mumasampuli emvura mukutarisa kwemvura yakasviba.
Organic nyaya inokuvadza zvakanyanya kumaindasitiri emvura masisitimu. Mvura ine huwandu hwakakura hwezvinhu zvakasikwa inosvibisa ion exchange resin kana ichipfuura nepakati peiyo desalination system, kunyanya anion exchange resins, izvo zvinozodzikisa huwandu hwekutsinhana kweresin. Organic nyaya inogona kuderedzwa ne50% mushure mekutanga (coagulation, kujekesa uye kusefa), asi haigone kubviswa mu desalination system, saka kazhinji inounzwa mubhailer kuburikidza nemvura yekudyisa, iyo inoderedza pH kukosha kwebhailer. mvura. Dzimwe nguva organic zvinhu zvinogona zvakare kuunzwa muutsi system uye condensate mvura, izvo zvinoderedza pH uye kukonzera system corrosion. Yakakwira organic matter yemukati mune inotenderera mvura system inosimudzira kuberekana kwehutachiona. Naizvozvo, ingave ye desalination, boiler yemvura kana inotenderera yemvura system, iyo yakaderera iyo COD, zviri nani, asi hapana yakabatana yekumisikidza index. Kana COD (KMnO4 nzira)> 5mg/L mukutenderera kwemvura inotonhorera, kunaka kwemvura kwakatanga kuderera.
Chemical kudiwa kweokisijeni (COD) chiratidzo chekuyera chiyero chemvura yakapfuma mune organic zvinhu, uye zvakare chimwe chezviratidzo zvakakosha zvekuyera dhigirii rekusvibiswa kwemvura. Nekuvandudzwa kwemaindasitiri uye kuwedzera kwehuwandu hwevanhu, mitumbi yemvura iri kuramba ichisvibiswa, uye kuvandudzwa kweCOD yekuona kwakawedzera zvishoma nezvishoma.
Mabviro ekuonekwa kweCOD anogona kuteverwa kumashure kuma1850s, apo matambudziko ekusvibiswa kwemvura akange akwezva vanhu. Pakutanga, COD yaishandiswa sechiratidzo chezvinwiwa zvine acidic kuyera kuwanda kweiyo organic zvinhu muzvinwiwa. Zvisinei, sezvo nzira yekuyera yakakwana yakanga isati yasimbiswa panguva iyoyo, pakanga pane kukanganisa kukuru mumigumisiro yekutsunga yeCOD.
Mukutanga kwezana ramakore re20, nekufambiswa kwemaitiro emazuva ano ekuongorora makemikari, nzira yekuona yeCOD yakavandudzwa zvishoma nezvishoma. Muna 1918, muongorori wemakemikari wekuGermany Hasse akatsanangura COD sehuwandu hwehuwandu hwezvinhu zvinodyiwa neoxidation mune acidic solution. Mushure meizvozvo, akakurudzira nzira itsva yekutemesa COD, iri kushandisa yakakwira-concentration chromium dioxide mhinduro seoxidant. Iyi nzira inogona kunyatso oxidize organic zvinhu mucarbon dioxide nemvura, uye kuyera kushandiswa kweoxidants mumhinduro isati uye mushure meiyo oxidation kuona kukosha kweCOD.
Zvisinei, zvikanganiso zvenzira iyi zvakabuda zvishoma nezvishoma. Kutanga, kugadzirira uye kushanda kwema reagents zvakanyanya kuoma, izvo zvinowedzera kuoma uye nguva yekuedza. Chechipiri, high-concentration chromium dioxide mhinduro zvinokuvadza kune zvakatipoteredza uye hazvibatsiri kune zvinoshanda. Naizvozvo, zvidzidzo zvakazotevera zvishoma nezvishoma zvakatsvaga yakapfava uye yakanyatsojeka COD yekugadzika nzira.
Mumakore ekuma1950, mutori wemakemikari wechiDutch Friis akagadzira nzira itsva yeCOD yekumisikidza, inoshandisa yakakwira-concentration persulfuric acid seoxidant. Iyi nzira iri nyore kushanda uye ine hupamhi hwepamusoro, iyo inovandudza zvakanyanya kushanda kweCOD yekuona. Nekudaro, kushandiswa kwepersulfuric acid kunewo dzimwe njodzi dzekuchengetedza, saka zvichiri kufanira kutarisisa kuchengetedzwa kwekushanda.
Zvadaro, nekukurumidza kusimudzira tekinoroji tekinoroji, iyo COD yekumisikidza nzira yakawana zvishoma nezvishoma otomatiki uye hungwaru. Mumakore ekuma1970, yekutanga COD otomatiki analyzer yakaonekwa, iyo inogona kuona zvizere otomatiki kugadzirisa uye kutariswa kwemasampuli emvura. Ichi chiridzwa hachingogadziri kurongeka uye kugadzikana kweCOD kutsunga, asi zvakare inovandudza zvakanyanya kushanda zvakanaka.
Nekukwidziridzwa kwekuziva kwezvakatipoteredza uye kuvandudzwa kwezvinodiwa zvekutonga, nzira yekuona yeCOD iri kuramba ichigadziridzwa. Mumakore achangopfuura, kuvandudzwa kweiyo photoelectric tekinoroji, electrochemical nzira uye biosensor tekinoroji yakasimudzira kuvandudzwa kweCOD yekuona tekinoroji. Semuenzaniso, tekinoroji yemagetsi inogona kuona zvirimo zveCOD mumasampuli emvura nekushandurwa kwezviratidzo zvephotoelectric, ine nguva pfupi yekuona uye kushanda kuri nyore. Nzira ye electrochemical inoshandisa electrochemical sensors kuyera COD values, iyo ine zvakanakira zvekunzwa kwakanyanya, kukurumidza kupindura uye hapana chinodiwa reagents. Biosensor tekinoroji inoshandisa biological zvinhu kunyatsoona organic zvinhu, izvo zvinovandudza iko kurongeka uye kujeka kweCOD kutsunga.
Nzira dzekuongorora dzeCOD dzakaita chirongwa chekuvandudza kubva kuongororo yemakemikari yechinyakare kuenda kuchiridzwa chemazuva ano, tekinoroji yemifananidzo, nzira dze electrochemical uye tekinoroji yebiosensor mumakumi mashoma apfuura. Nekufambira mberi kwesainzi uye tekinoroji uye kuwedzera kwekudiwa, tekinoroji yekuona COD ichiri kuvandudzwa uye kuvandudzwa. Mune ramangwana, zvinogona kucherechedzwa kuti sezvo vanhu vachinyanya kutarisisa nyaya dzekusvibiswa kwezvakatipoteredza, tekinoroji yekuona COD inoenderera mberi nekuva nzira inokurumidza, yakarurama uye yakavimbika yekuona mhando yemvura.
Parizvino, marabhoritari anonyanya kushandisa nzira mbiri dzinotevera kuona COD.
1. COD kusarudza nzira
Potassium dichromate yakajairika nzira, inozivikanwawo sereflux nzira (National Standard yePeople's Republic of China)
(I) Nheyo
Wedzera imwe chiyero che potassium dichromate uye catalyst sirivha sulfate kune mvura sampuli, kupisa uye reflux kweimwe nguva yenguva mune yakasimba acidic medium, chikamu che potassium dichromate chinoderedzwa ne oxidizable zvinhu mumvura sampuli, uye zvakasara. Potasium dichromate inogadzirwa neammonium ferrous sulfate. Iko kukosha kweCOD inoverengerwa zvichienderana nehuwandu hwe potassium dichromate inopedzwa.
Sezvo chiyero ichi chakagadzirwa muna 1989, pane zvakawanda zvakaipira pakuiyera neyazvino chiyero:
1. Zvinotora nguva yakawandisa, uye sampuli imwe neimwe inoda kuchinjwa kwemaawa maviri;
2. Iyo reflux midziyo inotora nzvimbo yakakura, ichiita kutsunga kwebatch kuome;
3. Mari yekuongorora yakakwira, kunyanya yesirivha sulfate;
4. Munguva yekutsunga kwekugadzirisa, tsvina yemvura reflux inoshamisa;
5. Toxic mercury salts inowanzoita kusvibiswa kwechipiri;
6. Nhamba ye reagents inoshandiswa yakakura, uye mari yezvinoshandiswa zvakanyanya;
7. Nzira yekuedza yakaoma uye haina kukodzera kusimudzirwa.
(II) Midziyo
1. 250mL ese-girazi reflux mudziyo
2. Chigadzirwa chekudziisa (choto chemagetsi)
3. 25mL kana 50mL acid burette, conical flask, pipette, volumetric flask, nezvimwewo.
(III) Reagents
1. Potassium dichromate mwero mhinduro (c1/6K2Cr2O7=0.2500mol/L)
2. Ferrocyanate chiratidzo mhinduro
3. Ammonium ferrous sulfate standard solution [c(NH4)2Fe(SO4)2·6H2O≈0.1mol/L] (gadzirisa usati washandisa)
4. Sulfuric acid-silver sulfate solution
Potassium dichromate yakajairika nzira
(IV) Matanho ekutsunga
Ammonium ferrous sulfate calibration: Chaizvo pipette 10.00mL ye potassium dichromate standard solution mu500mL conical flask, dilute kusvika pa110mL nemvura, zvishoma nezvishoma wowedzera 30mL yeconcentrated sulfuric acid, uye zunza zvakanaka. Mushure mekutonhodza, wedzera madonhwe matatu eferrocyanate indicator solution (inenge 0.15mL) uye titrate neammonium ferrous sulfate solution. Mhedziso ndeye apo ruvara rwemushonga unoshanduka kubva kune yero kusvika kune yebhuruu-yegirinhi kusvika kune yakatsvuka.
(V) Kutsunga
Tora 20mL yesampuli yemvura (kana zvichidikanwa, tora zvishoma uye wowedzera mvura ku20 kana kudzikisa usati watora), wedzera 10mL ye potassium dichromate, plug mu reflux mudziyo, wobva wawedzera 30mL ye sulfuric acid uye sirivheri sulfate, kupisa uye reflux kwe2h. . Mushure mekutonhora, sukurudza condenser chubhu madziro ne90.00mL yemvura uye bvisa conical flask. Mushure mekunge mushonga wacho watonhodzwa zvakare, wedzera madonhwe matatu eferrous acid indicator solution uye titrate neammonium ferrous sulfate standard solution. Rudzi rwemushonga unoshanduka kubva kune yero kusvika kune bhuruu-ruvara rwegirini kusvika dzvuku dzvuku, inova ndiyo yekupedzisira. Rekodha huwandu hweammonium ferrous sulfate standard solution. Paunenge uchiyera sampu yemvura, tora 20.00mL yemvura yakadzokororwa uye ita bvunzo isina chinhu zvinoenderana nematanho ekushandisa mamwe chete. Rekodha huwandu hweammonium ferrous sulfate yakajairwa mhinduro inoshandiswa mune isina chinhu titration.
Potassium dichromate yakajairika nzira
(VI) Kuverenga
CODCr(O2, mg/L)=[8×1000(V0-V1)·C]/V
(VII) Chengetedzo
1. Nhamba yakawanda ye chloride ion yakasanganiswa ne 0.4g mercuric sulfate inogona kusvika 40mg. Kana 20.00mL mvura sampu yakatorwa, iyo yakanyanya chloride ion concentration ye2000mg/L inogona kuomeswa. Kana huwandu hwe chloride ion hwakaderera, huwandu hushoma hwemercuric sulfate hunogona kuwedzerwa kuchengetedza mercuric sulfate: chloride ions = 10: 1 (W/W). Kana huwandu hushoma hwemercuric chloride huchidzika, hazvikanganisi kutsunga.
2. Huwandu hweCOD hwakatarwa neiyi nzira ndeye 50-500mg/L. Kumasampuli emvura ane makemikari okisijeni anodiwa isingasviki 50mg/L, 0.0250mol/L potassium dichromate standard solution inofanira kushandiswa pachinzvimbo. 0.01mol/L ammonium ferrous sulfate yakajairwa mhinduro inofanira kushandiswa kudzosera kumashure. Kune masampuli emvura ane COD yakakura kupfuura 500mg/L, nyungudusa usati watsunga.
3. Mushure mokunge sampu yemvura inopisa uye yakasvibiswa, iyo yakasara ye potassium dichromate mumhinduro inofanira kuva 1 / 5-4 / 5 yehuwandu hwakawedzerwa.
4. Paunenge uchishandisa potassium hydrogen phthalate yakajairwa mhinduro yekutarisa kunaka uye kushanda tekinoroji ye reagent, sezvo theoretical CODCr yega yega potassium hydrogen phthalate iri 1.176g, 0.4251g ye potassium hydrogen phthalate (HOOCC6H4COOK) inonyungudika mumvura yakasanganiswa zvakare, kuendeswa kune 1000mL volumetric flask, uye yakanyungudutswa kune mucherechedzo nemvura yakadzokororwa kuti iite 500mg/L CODcr yakajairwa mhinduro. Gadzirira mutsva kana washandiswa.
5. Mhedzisiro yeCODCr inofanirwa kuchengetedza manhamba mana akakosha.
6. Panguva yekuedza kwega kwega, iyo ammonium ferrous sulfate yakajairwa titration mhinduro inofanirwa kuverengerwa, uye shanduko yekumisa inofanirwa kutariswa zvakanyanya kana tembiricha yekamuri yakakwira. (Unogonawo kuwedzera 10.0ml ye potassium dichromate standard solution kune isina chinhu mushure mekuti titration uye titrate neammonium ferrous sulfate kusvika kumagumo.)
7. Sampu yemvura inofanira kuchengetwa yakachena uye kuyerwa nokukurumidza sezvinobvira.
Zvakanakira:
Kurongeka kwepamusoro: Reflux titration imhando yeCOD yekumisikidza nzira. Mushure menguva refu yekuvandudzwa uye kusimbiswa, huchokwadi hwayo hwave huchizivikanwa zvakanyanya. Inogona kunyatso ratidza izvo chaizvo zviri mukati meiyo organic matter mumvura.
Wide application: Iyi nzira inokodzera mhando dzakasiyana dzemasampuli emvura, kusanganisira yakakwira-concentration uye yakaderera-yakadzika organic tsvina.
Maitiro ekushanda: Kune akadzama maitiro ekushanda uye maitiro, ayo ari nyore kune vashandisi kugona uye kuita.
Zvakaipa:
Kutora nguva: Reflux titration inowanzotora maawa akati wandei kupedzisa kugadzwa kwemuenzaniso, izvo zviri pachena kuti hazvienderane nemamiriro ezvinhu apo mhedzisiro inoda kuwanikwa nekukurumidza.
High reagent kushandiswa: Iyi nzira inoda kushandiswa kwemamwe makemikari reagents, izvo zvisingadhuri chete, asiwo zvinosvibisa zvakatipoteredza kusvika pamwero wakati.
Kushanda kwakaoma: Mushandi anofanirwa kuve neruzivo rwemakemikari uye hunyanzvi hwekuyedza, zvikasadaro zvinogona kukanganisa iko kurongeka kwemhedzisiro.
2. Rapid digestion spectrophotometry
(I) Nheyo
Muenzaniso wacho unowedzerwa nehuwandu hunozivikanwa hwe potassium dichromate solution, mune yakasimba sulfuric acid medium, nesirivha sulfate sechinhu chinokonzera, uye mushure mekushisa kwepamusoro-kupisa, kukosha kweCOD kunotarirwa nemidziyo yephotometric. Sezvo nzira iyi ine nguva pfupi yekutsunga, kusvibiswa kudiki kwechipiri, vhoriyamu diki reagent uye mutengo wakaderera, marabhoritari mazhinji anoshandisa nzira iyi. Zvisinei, iyi nzira ine mari yepamusoro yezviridzwa uye mari shoma yekushandisa, iyo yakakodzera kushandiswa kwenguva refu kwezvikamu zveCOD.
(II) Midziyo
Midziyo yekune dzimwe nyika yakagadzirwa kare, asi mutengo wakanyanya kwazvo, uye nguva yekutsunga yakareba. Mutengo wereagent kazhinji haugoneki kune vashandisi, uye iko kurongeka hakuna kunyanya kukwira, nekuti zviyero zvekutarisa zvezviridzwa zvekunze zvakasiyana neaya emunyika yangu, kunyanya nekuti chiyero chekurapa kwemvura uye hurongwa hwekutonga kwenyika dzekunze akasiyana neangu. country; iyo yekukurumidza digestion spectrophotometry nzira inonyanya kuenderana nemaitiro akajairika emidziyo yemumba. Iyo inokonzeresa kukurumidza kutsunga kweCOD nzira ndiyo yekugadzira mwero weiyi nzira. Yakagadzirwa kare sekutanga kwema1980. Mushure memakore anopfuura makumi matatu ekushandisa, yave chiyero cheindasitiri yekuchengetedzwa kwezvakatipoteredza. Mumba 5B chiridzwa chakashandiswa zvakanyanya mukutsvagisa kwesainzi uye nekutarisa zviri pamutemo. Zviridzwa zvemumba zvave zvichishandiswa zvakanyanya nekuda kwemutengo wazvo zvakanakira uye nenguva yekutevera-kutengesa sevhisi.
(III) Matanho ekutsunga
Tora 2.5ml sample—–add reagent—–digest for 10 minutes—–itonhorera kwemaminetsi maviri—–dururira mundiro yecolorimetric—–chishandiso chinoratidza zvakananga COD kusungwa kwesampuli.
(IV) Kuchengetedza
1. High-chlorine mvura samples inofanira kushandisa high-chlorine reagent.
2. Mvura inorasa inenge 10ml, asi ine acidic zvakanyanya uye inofanira kuunganidzwa uye kugadziriswa.
3. Iva nechokwadi chekuti nzvimbo inotumira chiedza checuvette yakachena.
Zvakanakira:
Kukurumidza kukurumidza: Nzira yekukurumidza inongotora maminetsi mashoma kusvika kumaminitsi anopfuura gumi kuti upedze kugadzwa kwemuenzaniso, wakanyatsokodzera mamiriro ezvinhu apo mhedzisiro inoda kuwanikwa nekukurumidza.
Kushandiswa kushoma reagent: Kuenzaniswa neiyo reflux titration nzira, nzira yekukurumidza inoshandisa mashoma emakemikari reagents, ine mutengo wakaderera, uye ine zvishoma kukanganisa nharaunda.
Kushanda kuri nyore: Matanho ekushanda kweiyo nzira yekukurumidza ari nyore, uye mushandisi haafanire kuve neruzivo rwemakemikari akawandisa uye hunyanzvi hwekuyedza.
Zvakaipa:
Kunyatsodzika zvishoma: Sezvo nzira yekukurumidza ichiwanzoshandisa mamwe maitiro akareruka emakemikari uye nzira dzekuyera, huchokwadi hwayo hunogona kudzika zvishoma pane reflux titration nzira.
Yakaganhurirwa chiyero chekushandisa: Iyo yekukurumidza nzira inonyanya kukodzera kugadzwa kweiyo yakaderera-yakagadziriswa organic tsvina. Kune yakakwira-concentration tsvina yemvura, mhedzisiro yayo yekutsunga inogona kukanganiswa zvakanyanya.
Kukanganiswa nekukanganisa zvinhu: Iyo nzira yekukurumidza inogona kuburitsa zvikanganiso zvakakura mune zvimwe zviitiko zvakakosha, senge paine zvimwe zvinokanganisa mumuenzaniso wemvura.
Muchidimbu, iyo reflux titration nzira uye nzira yekukurumidza imwe neimwe ine zvayakanakira nezvayakaipira. Ndeipi nzira yekusarudza zvinoenderana neiyo chaiyo application mamiriro uye zvinodiwa. Kana kurongeka kwepamusoro uye kushanda kwakafara kuchidikanwa, reflux titration inogona kusarudzwa; apo mhinduro dzinokurumidza dzinodiwa kana nhamba yakawanda yemvura inogadziriswa, nzira yekukurumidza isarudzo yakanaka.
Lianhua, semugadziri wemvura yekuyedza zviridzwa kwemakore makumi mana nemaviri, yakagadzira maminitsi makumi maviri.COD nekukurumidza digestion spectrophotometrynzira. Mushure mehuwandu hukuru hwekuenzanisa kwekuenzanisa, yakakwanisa kuwana kukanganisa kwepasi pe5%, uye ine zvakanakira kushanda nyore, mhedzisiro inokurumidza, mutengo wakaderera uye nguva pfupi.
Nguva yekutumira: Jun-07-2024
