A na-akpọkwa ọchịchọ oxygen kemịkalụ kemịkalụ ikuku oxygen (achọrọ oxygen kemịkalụ), nke a na-akpọ COD. Ọ bụ iji kemịkalụ oxidants (dị ka potassium permanganate) oxidize na decompose oxidizable ihe na mmiri (dị ka organic okwu, nitrite, ferrous nnu, sulfide, wdg), wee gbakọọ oriri oxygen dabere na ego nke fọdụrụnụ. oxidant. Dị ka ọchịchọ oxygen biochemical (BOD), ọ bụ ihe dị mkpa na-egosi mmetọ mmiri. Ngalaba COD bụ ppm ma ọ bụ mg/L. Ọnụ ahịa dị ntakịrị, ka mmetọ mmiri na-adị ọkụ.
Ihe ndị na-ebelata ihe dị na mmiri gụnyere ihe dị iche iche nke organic, nitrite, sulfide, nnu ferrous, wdg. Ma nke bụ isi bụ ihe ndị dị ndụ. Ya mere, a na-ejikarị achọ oxygen oxygen (COD) eme ihe dị ka ihe ngosi iji tụọ ọnụọgụ organic na mmiri. Ka ọ̀tụ̀tụ̀ ikuku oxygen na-adịwanye ukwuu, otú ahụ ka mmetọ mmiri na-esi n'ihe ndị dị ndụ na-adị njọ karị. Mkpebi nke ọchịchọ oxygen oxygen (COD) dịgasị iche na mkpebi nke ibelata ihe dị na ihe nlele mmiri na usoro mkpebi. Ụzọ a na-ejikarị eme ihe ugbu a bụ usoro acidic potassium permanganate oxidation na usoro potassium dichromate oxidation. Usoro potassium permanganate (KMnO4) nwere ọnụ ọgụgụ oxidation dị ala, mana ọ dị mfe. Enwere ike iji ya chọpụta uru ntule nke ọdịnaya organic na nlele mmiri na mmiri dị ọcha na mmiri dị n'ime ala. Usoro potassium dichromate (K2Cr2O7) nwere oke oxidation ọnụego yana ezigbo nrụpụta. Ọ dabara maka ịchọpụta mkpokọta ihe ndị na-emepụta ihe na ihe nlele mmiri na nlekota mmiri mkpofu.
Ihe ndị dị ndụ na-emerụ ahụ maka usoro mmiri mmepụta ihe. Mmiri nke nwere nnukwu ihe na-emepụta ihe ga-emetọ resins mgbanwe ion mgbe ọ na-agafe na usoro nsị, karịsịa anion Exchange resins, nke ga-ebelata ikike mgbanwe nke resin. Enwere ike ibelata ihe ndị dị ndụ site na 50% mgbe emechara ọgwụgwọ (coagulation, nkọwa na filtration), ma enweghị ike iwepụ ya na usoro nkwụsịtụ, ya mere a na-ebutekarị ya n'ime ọkụ ọkụ site na mmiri nri, nke na-ebelata pH uru nke onye na-ekpo ọkụ. mmiri. Mgbe ụfọdụ, a na-ebutekwa ihe ndị dị ndụ n'ime sistemu uzuoku na mmiri condensate, nke ga-ebelata pH ma mee ka mmebi usoro. Ọdịnaya dị elu nke organic na sistem mmiri na-ekesa ga-akwalite mmeputakwa microbial. Ya mere, ma maka desalination, ji esi mmiri ọkụ ma ọ bụ na-ekesa mmiri usoro, na-ebelata COD, mma, ma ọ dịghị otu jikọrọ mmachi index. Mgbe COD (usoro KMnO4)> 5mg/L n'ime sistemu mmiri jụrụ oyi, ogo mmiri amalitela ịka njọ.
Ọchịchọ oxygen oxygen (COD) bụ ihe nleba anya ogo nke mmiri bara ụbara n'ihe ndị dị ndụ, na ọ bụkwa otu n'ime ihe ndị dị mkpa maka ịlele ogo mmetọ mmiri. Site na mmepe nke mmepụta ihe na mmụba nke ọnụ ọgụgụ ndị mmadụ, mmiri na-emetọwanyewanye, na mmepe nke nchọpụta COD ejiriwo nwayọọ nwayọọ na-akawanye mma.
Enwere ike ịchọta mmalite nchọpụta COD laa azụ na 1850s, mgbe nsogbu mmetọ mmiri dọtara mmasị ndị mmadụ. Na mbụ, a na-eji COD mee ihe dị ka ihe na-egosi ihe ọṅụṅụ acidic iji tụọ ntinye nke ihe ndị dị n'ime ihe ọṅụṅụ. Agbanyeghị, ebe ọ bụ na emebeghị usoro nha zuru oke n'oge ahụ, enwere nnukwu mperi na nsonaazụ mkpebi COD.
Na mmalite narị afọ nke 20, na ọganihu nke usoro nyocha kemịkalụ ọgbara ọhụrụ, usoro nchọpụta nke COD ji nwayọọ nwayọọ na-emeziwanye. Na 1918, German chemist Hasse kọwapụtara COD dị ka mkpokọta mkpụrụ ndụ ihe ọkụkụ nke oxidation riri na ngwọta acidic. N'ikpeazụ, ọ tụpụtara usoro mkpebi mkpebi COD ọhụrụ, nke bụ iji ngwọta chromium dioxide na-etinye uche dị elu dị ka oxidant. Usoro a nwere ike itinye ihe ndị dị ndụ n'ụzọ dị irè n'ime carbon dioxide na mmiri, wee tụọ oriri nke oxidants na ngwọta tupu na mgbe oxidation iji chọpụta uru COD.
Otú ọ dị, adịghị ike nke usoro a ji nwayọọ nwayọọ pụta. Nke mbụ, nkwadebe na ọrụ nke reagents dị mgbagwoju anya, nke na-eme ka ihe isi ike na-ewe oge nke nnwale ahụ. Nke abụọ, ihe ngwọta chromium dioxide dị elu na-emerụ ahụ na gburugburu ebe obibi na ọ dịghị mma maka ngwa bara uru. Ya mere, ọmụmụ ihe ndị sochirinụ ejirila nwayọọ nwayọọ chọọ ụzọ mkpebi COD dị mfe ma dịkwa mma.
Na 1950s, Dutch chemist Friis chepụtara usoro mkpebi mkpebi COD ọhụrụ, nke na-eji acid persulfuric dị elu dị ka oxidant. Usoro a dị mfe iji rụọ ọrụ ma nwee oke ziri ezi, nke na-eme ka nchọpụta COD dịkwuo mma. Otú ọ dị, iji persulfuric acid nwekwara ụfọdụ ihe ize ndụ nchekwa, ya mere ọ ka dị mkpa ịṅa ntị na nchekwa nke ọrụ.
N'ikpeazụ, site na mmepe ngwa ngwa nke teknụzụ ngwá ọrụ, usoro mkpebi COD ejirila nwayọọ nwayọọ nweta akpaaka na ọgụgụ isi. Na 1970s, mbụ COD akpaka analyzer pụtara, nke nwere ike na-aghọta zuru akpaka nhazi na nchọpụta nke mmiri samples. Ngwá ọrụ a abụghị naanị na-eme ka izi ezi na nkwụsi ike nke mkpebi COD dịkwuo mma, kamakwa ọ na-eme ka arụmọrụ ọrụ dịkwuo mma.
Site na nkwalite nke mmata gburugburu ebe obibi na nkwalite nke usoro iwu chọrọ, a na-emeziwanye usoro nchọpụta nke COD mgbe niile. N'ime afọ ndị na-adịbeghị anya, mmepe nke teknụzụ fotoelectric, ụzọ electrochemical na teknụzụ biosensor akwalitela ihe ọhụrụ nke teknụzụ nchọpụta COD. Dịka ọmụmaatụ, teknụzụ fotoelectric nwere ike ikpebi ọdịnaya COD n'ime ihe nlele mmiri site na mgbanwe nke akara fotoelectric, yana oge nchọpụta dị mkpụmkpụ na ọrụ dị mfe. Usoro electrochemical na-eji ihe mmetụta electrochemical tụọ ụkpụrụ COD, nke nwere uru nke uche dị elu, nzaghachi ngwa ngwa na enweghị mkpa maka reagents. Teknụzụ Biosensor na-eji ihe ndị dị ndụ na-achọpụta kpọmkwem ihe organic, nke na-eme ka izi ezi na nkọwapụta nke mkpebi COD dị mma.
Ụzọ nchọpụta COD emeela usoro mmepe site na nyocha kemịkalụ ọdịnala ruo na ngwa ọgbara ọhụrụ, teknụzụ fotoelectric, ụzọ electrochemical na teknụzụ biosensor n'ime iri afọ ole na ole gara aga. Site na ọganihu nke sayensị na teknụzụ yana mmụba nke ọchịchọ, teknụzụ nchọpụta COD ka na-emeziwanye ma na-emepụta ihe ọhụrụ. N'ọdịnihu, enwere ike ịhụ na ka ndị mmadụ na-etinyekwu uche na ihe ndị metụtara mmetọ gburugburu ebe obibi, nkà na ụzụ nchọpụta COD ga-etolite n'ihu ma ghọọ ngwa ngwa ngwa ngwa, nke ziri ezi na nke a pụrụ ịdabere na ya usoro nchọpụta mmiri.
Ugbu a, ụlọ nyocha na-ejikarị ụzọ abụọ a chọpụta COD.
1. Usoro mkpebi COD
Usoro ọkọlọtọ Potassium dichromate, nke a makwaara dị ka usoro reflux (National Standard of the People's Republic of China)
(I) Ụkpụrụ
Tinye ụfọdụ potassium dichromate na catalyst ọlaọcha sulfate na mmiri sample, okpomọkụ na reflux maka oge ụfọdụ na a siri ike acidic media, akụkụ nke potassium dichromate na-ebelata site oxidizable bekee na mmiri sample, na ndị fọdụrụ. A na-etinye potassium dichromate na ammonium ferrous sulfate. A na-agbakọ uru COD dabere na ọnụọgụ potassium dichromate riri.
Ebe ọ bụ na ewepụtara ọkọlọtọ a na 1989, enwere ọtụtụ ọghọm dị na iji ọkọlọtọ ugbu a tụọ ya:
1. Ọ na-ewe oge dị ukwuu, na nke ọ bụla sample kwesịrị ka reflux maka 2 awa;
2. The reflux akụrụngwa ogide a nnukwu ohere, na-eme ka ogbe mkpebi siri ike;
3. Ọnụ ego nyocha dị elu, karịsịa maka sulfate ọlaọcha;
4. N'oge usoro mkpebi siri ike, mkpofu mmiri reflux dị ịtụnanya;
5. Nnu mercury na-egbu egbu na-enwekarị mmetọ nke abụọ;
6. Ọnụ ọgụgụ nke reagents na-eji buru ibu, na ọnụ ahịa ihe oriri dị elu;
7. Usoro ule dị mgbagwoju anya na ọ bụghị maka nkwalite.
(II) Akụrụngwa
1. 250mL niile-glass reflux ngwaọrụ
2. Igwe ọkụ (ọkụ eletrik)
3. 25mL ma ọ bụ 50mL acid burette, conical flask, pipette, volumetric flask, wdg.
(III) Reagents
1. Potassium dichromate ọkọlọtọ ngwọta (c1/6K2Cr2O7=0.2500mol/L)
2. Ferrocyanate egosi ngwọta
3. Ammonium ferrous sulfate ọkọlọtọ ngwọta [c (NH4) 2Fe (SO4) 2 · 6H2O≈0.1mol / L] (calibrate tupu ojiji)
4. Sulfuric acid-silver sulfate ngwọta
Potassium dichromate usoro ọkọlọtọ
(IV) Usoro mkpebi
Ammonium ferrous sulfate calibration: N'ezie pipette 10.00mL nke potassium dichromate ọkọlọtọ ngwọta n'ime 500mL conical flask, itughari ka ihe 110mL na mmiri, jiri nwayọọ nwayọọ tinye 30mL nke sulfuric acid gbadoro anya, ma maa jijiji nke ọma. Mgbe ọ dị jụụ, tinye 3 tụlee nke ihe ngosi ferrocyanate (ihe dịka 0.15mL) na titrate na ammonium ferrous sulfate solution. Ebe njedebe bụ mgbe agba nke ngwọta na-agbanwe site na odo na-acha anụnụ anụnụ-acha akwụkwọ ndụ na agba aja aja na-acha uhie uhie.
(V) Mkpebi
Were 20ml nke mmiri sample (ọ bụrụ na ọ dị mkpa, were obere ma tinye mmiri na 20 ma ọ bụ itughari tupu ewere), tinye 10mL nke potassium dichromate, tinye na reflux ngwaọrụ, wee tinye 30mL nke sulfuric acid na silver sulfate, okpomọkụ na reflux maka 2h. . Mgbe ọ dị jụụ, kpochaa mgbidi condenser na mmiri 90.00mL wee wepụ flask conical. Mgbe emechara ihe ngwọta ahụ ọzọ, tinye 3 tụlee nke ferrous acid ngwọta na titrate na ammonium ferrous sulfate ọkọlọtọ ngwọta. Agba nke ngwọta na-agbanwe site na odo na-acha anụnụ anụnụ-acha akwụkwọ ndụ na-acha uhie uhie, nke bụ njedebe njedebe. Dekọọ ọnụọgụ ammonium ferrous sulfate ọkọlọtọ ngwọta. Mgbe ị na-atụ ihe nlele mmiri, were 20.00mL nke mmiri redistilled wee mee nnwale efu dịka otu usoro ọrụ si dị. Dekọọ ọnụọgụ ammonium ferrous sulfate ọkọlọtọ ejiri na titration oghere.
Potassium dichromate usoro ọkọlọtọ
(VI) Mgbakọ
CODCR (O2, mg/L)=[8×1000(V0-V1)·C]/V
(VII) Akpachara anya
1. Oke kachasị nke ion ion chloride nke nwere 0.4g mercuric sulfate nwere ike iru 40mg. Ọ bụrụ na ewere 20.00ml mmiri sample, kacha chloride ion ịta nke 2000mg/L nwere ike mgbagwoju. Ọ bụrụ na ntinye nke ion chloride dị ala, enwere ike ịgbakwunye obere mercuric sulfate iji debe mercuric sulfate: ion chloride = 10: 1 (W / W). Ọ bụrụ na obere mercuric chloride na-ebuli elu, ọ naghị emetụta mkpebi ahụ.
2. Oke COD kpebisiri ike na usoro a bụ 50-500mg / L. Maka ihe nlele mmiri nwere oxygen kemịkal chọrọ ihe na-erughị 50mg/L, 0.0250mol/L potassium dichromate ọkọlọtọ ngwọta kwesịrị iji kama. 0.01mol/L ammonium ferrous sulfate ọkọlọtọ ngwọta kwesịrị iji maka azụ titration. Maka ihe nlele mmiri nwere COD karịrị 500mg / L, gbanye ha tupu mkpebi.
3. Mgbe ihe nlele mmiri na-ekpo ọkụ na reflux, ihe fọdụrụ nke potassium dichromate na ngwọta kwesịrị ịbụ 1 / 5-4 / 5 nke ego agbakwunyere.
4. Mgbe ị na-eji potassium hydrogen phthalate ọkọlọtọ ngwọta iji lelee àgwà na teknụzụ ọrụ nke reagent, ebe ọ bụ na usoro CODCr nke gram ọ bụla nke potassium hydrogen phthalate bụ 1.176g, 0.4251g nke potassium hydrogen phthalate (HOOCC6H4COOK) na-agbaze na mmiri redistilled, bufee ya na 1000mL volumetric flask, ma tinye ya na akara na mmiri redistilled iji mee ka ọ bụrụ 500mg/L CODcr ọkọlọtọ ngwọta. Kwadebe ya ọhụrụ mgbe ejiri ya.
5. Nsonaazụ mkpebi CODCR kwesịrị idowe ọnụọgụ anọ dị mkpa.
6. N'oge nnwale ọ bụla, ammonium ferrous sulfate standard titration kwesịrị ka a na-edozi ya, na mgbanwe ntinye uche kwesịrị ịkwụ ụgwọ nlebara anya pụrụ iche mgbe ụlọ okpomọkụ dị elu. (Ị nwekwara ike ịgbakwunye 10.0ml nke potassium dichromate ọkọlọtọ ngwọta na oghere mgbe titration na titrate na ammonium ferrous sulfate na njedebe njedebe.)
7. Ekwesịrị idobe ihe nlele mmiri dị ọhụrụ ma tụọ ngwa ngwa o kwere omume.
Uru:
Izi ezi dị elu: Reflux titration bụ usoro mkpebi COD kpochapụrụ. Mgbe ogologo oge mmepe na nkwenye gasịrị, a matala izi ezi ya nke ọma. Ọ nwere ike na-egosipụta nke ọma n'ezie ọdịnaya nke organic okwu na mmiri.
Ngwa sara mbara: Usoro a dabara adaba maka ụdị mmiri dị iche iche, gụnyere itinye uche dị elu na obere mmiri mkpofu ahịhịa.
Nkọwapụta ọrụ: Enwere ụkpụrụ na usoro ọrụ zuru ezu, nke dị mma maka ndị na-arụ ọrụ iji mara ma mejuputa.
Ihe ọghọm:
Na-eri oge: Reflux titration na-ewekarị awa ole na ole iji mezue mkpebi nke ihe nlele, nke doro anya na ọ naghị akwado ọnọdụ ebe ọ dị mkpa ka a nweta nsonaazụ ngwa ngwa.
Nri reagent dị elu: Usoro a chọrọ ka a na-eji reagents ndị ọzọ kemịkalụ, nke na-abụghị naanị ọnụ ahịa, kamakwa na-emerụ gburugburu ebe obibi ruo n'ókè ụfọdụ.
Ịrụ ọrụ mgbagwoju anya: Onye na-arụ ọrụ kwesịrị inwe ụfọdụ ihe ọmụma kemịkalụ na nkà nnwale, ma ọ bụghị ya, ọ nwere ike imetụta izi ezi nke nsonaazụ mkpebi.
2. Ngwa ngwa mgbaze spectrophotometry
(I) Ụkpụrụ
A na-agbakwunye ihe nlele ahụ na ihe ngwọta potassium dichromate a maara nke ọma, na sulfuric acid siri ike, na ọlaọcha sulfate dị ka ihe na-eme ka ọ bụrụ ihe na-eme ka ọ bụrụ ihe na-eme ka ọ bụrụ ihe na-eme ka ọ bụrụ ihe na-eme ka ọ dịkwuo elu, na-ekpebi uru COD site na ngwa fotometric. Ebe ọ bụ na usoro a nwere obere oge mkpebi siri ike, obere mmetọ nke abụọ, obere reagent olu na ọnụ ala dị ala, ọtụtụ ụlọ nyocha na-eji usoro a ugbu a. Otú ọ dị, usoro a nwere ọnụ ahịa ngwá ọrụ dị elu na ọnụ ala dị ala, nke kwesịrị ekwesị maka iji ogologo oge nke COD nkeji.
(II) Akụrụngwa
E mepụtara akụrụngwa mba ọzọ na mbụ, mana ọnụahịa dị oke elu, na oge mkpebi siri ike dị ogologo. The reagent price bụ n'ozuzu enweghị ego maka ọrụ, na izi ezi adịghị nnọọ elu, n'ihi na nlekota ụkpụrụ nke mba ọzọ ngwá dị iche na nke mba m, tumadi n'ihi na mmiri ọgwụgwọ larịị na management usoro nke mba ọzọ dị iche na nke m. obodo; usoro mgbaze ngwa ngwa spectrophotometry na-adabere na usoro a na-ahụkarị nke ngwa ụlọ. Mkpebi ngwa ngwa catalytic nke usoro COD bụ ụkpụrụ nhazi nke usoro a. Emepụtara ya na mmalite afọ 1980. Mgbe ihe karịrị afọ 30 nke ngwa, ọ ghọwo ọkọlọtọ nke ụlọ ọrụ nchebe gburugburu ebe obibi. Ejila ngwa ụlọ 5B mee ihe n'ọtụtụ ebe na nyocha sayensị na nleba anya gọọmentị. A na-eji ngwa ụlọ eme ihe n'ọtụtụ ebe n'ihi uru ọnụahịa ha na ọrụ ọrịre ahịa n'oge.
(III) Usoro mkpebi
Were nlele 2.5ml --gbakwunye reagent --gbarie maka nkeji 10--ọ dị jụụ maka nkeji 2 --wunye n'ime efere colorimetric - ihe ngosi akụrụngwa na-egosipụta ozugbo ntinye COD nke ihe nlele ahụ.
(IV) Akpachara anya
1. Akwa-chlorine mmiri sample kwesịrị iji elu-chlorine reagent.
2. Mmiri mmiri na-ekpofu ihe dị ka 10ml, ma ọ bụ nnukwu acidic na ekwesịrị ịnakọta ya na nhazi ya.
3. Gbaa mbọ hụ na elu na-ebufe ọkụ nke cuvette dị ọcha.
Uru:
Ọsọ ọsọ ọsọ: Usoro ngwa ngwa na-ewekarị nkeji ole na ole ruo ihe karịrị nkeji iri iji mezue mkpebi nke ihe nlele, nke dabara adaba maka ọnọdụ ebe achọrọ nsonaazụ ngwa ngwa.
Oriri reagent pere mpe: E jiri ya tụnyere usoro reflux titration, usoro ngwa ngwa na-eji reagents kemịkalụ pere mpe, nwere ọnụ ahịa dị ala, yana enwechaghị mmetụta na gburugburu ebe obibi.
Ịrụ ọrụ dị mfe: Usoro ọrụ nke usoro ngwa ngwa dị mfe, na onye na-arụ ọrụ adịghị mkpa inwe ihe ọmụma kemịkalụ dị elu na nkà nyocha.
Ihe ọghọm:
Izi ezi dị ntakịrị ala: Ebe ọ bụ na usoro ngwa ngwa na-ejikarị ụfọdụ mmeghachi omume kemịkalụ dị mfe yana ụzọ nha, izi ezi ya nwere ike ịdị ntakịrị ala karịa usoro reflux titration.
Oke ngwa nke nwere oke: Usoro ngwa ngwa dabara adaba maka ikpebi mmiri mkpofu ahịhịa na-adị obere. Maka mmiri mkpofu na-etinye uche dị elu, nsonaazụ mkpebi ya nwere ike imetụta nke ukwuu.
Ihe nnyonye anya na-emetụta: Usoro ngwa ngwa nwere ike ịmepụta nnukwu njehie na ụfọdụ ihe pụrụ iche, dịka mgbe enwere ụfọdụ ihe na-etinye aka na mmiri mmiri.
Na nchịkọta, usoro reflux titration na usoro ngwa ngwa nke ọ bụla nwere uru na ọghọm nke ya. Kedu usoro ịhọrọ dabere na ọnọdụ ngwa na mkpa akọwapụtara. Mgbe achọrọ oke nkenke na ngwa ngwa, enwere ike ịhọrọ reflux titration; mgbe achọrọ nsonaazụ ngwa ngwa ma ọ bụ na-edozi ọnụ ọgụgụ dị ukwuu nke mmiri mmiri, usoro ngwa ngwa bụ nhọrọ dị mma.
Lianhua, dị ka onye na-emepụta ngwá ọrụ nnwale mmiri maka afọ 42, ewepụtala nkeji 20.COD spectrophotometry mgbaze ngwa ngwausoro. Mgbe ọnụ ọgụgụ dị ukwuu nke nyocha nyocha, ọ na-enwe ike nweta njehie nke na-erughị 5%, ma nwee uru nke ọrụ dị mfe, nsonaazụ ngwa ngwa, ọnụ ala na obere oge.
Oge nzipu: Jun-07-2024
