Introduction to DPD colorimetry

ʻO ka DPD spectrophotometry ke ʻano maʻamau no ka ʻike ʻana i ke koena chlorine manuahi a me ka nui o ke koena chlorine ma ke kūlana aupuni o Kina "Water Quality Vocabulary and Analytical Methods" GB11898-89, i hoʻomohala ʻia e ka American Public Health Association, ka American Water Works Association a me ka Water Pollution Control. Huihui. I ka hoʻoponopono ʻia ʻo "Standard Test Methods for Water and Wastewater", ua hoʻomohala ʻia ke ʻano DPD mai ka paʻi 15th a ua ʻōlelo ʻia ʻo ia ke ʻano maʻamau no ka hoʻāʻo ʻana i ka chlorine dioxide.
Nā pōmaikaʻi o ke ʻano DPD
Hiki iā ia ke hoʻokaʻawale i ka chlorine dioxide mai nā ʻano like ʻole o ka chlorine (me ka chlorine koena manuahi, ka nui o ke koena chlorine a me ka chlorite, etc.), e maʻalahi ka hana ʻana i nā hoʻokolohua colorimetric. ʻAʻole pololei kēia ʻano hana e like me ka amperometric titration, akā lawa nā hopena no nā kumu maʻamau.
kumukānāwai
Ma lalo o nā kūlana o ka pH 6.2 ~ 6.5, ClO2 e hana mua me DPD e hana i kahi ʻulaʻula, akā ʻike ʻia ka nui a hiki i ka hapalima o ka nui o ka chlorine i loaʻa (e like me ka hoʻemi ʻana i ka ClO2 i nā ion chlorite). Inā ʻakika ʻia kahi laʻana wai ma ke alo o ka iodide, chlorite a me chlorate pū kekahi, a i ka wā e hoʻokaʻawale ʻia e ka hoʻohui ʻana i ka bicarbonate, ua like ka waihoʻoluʻu i ka huina o ka chlorine i loaʻa o ClO2. Hiki ke pale ʻia ka hoʻopili ʻana o ka chlorine manuahi ma ka hoʻohui ʻana i ka glycine. ʻO ke kumu, hiki i ka glycine ke hoʻololi koke i ka chlorine manuahi i loko o ka waikawa aminoacetic chlorinated, akā ʻaʻohe hopena i ka ClO2.
ʻO ka pāpaʻi iodate waihona waihona maʻamau, 1.006g/L: Kauona 1.003g potassium iodate (KIO3, maloʻo ma 120 ~ 140 ° C no 2 mau hola), hoʻoheheʻe i ka wai maʻemaʻe kiʻekiʻe, a hoʻololi i ka leo 1000ml.
E hoʻoheheʻe i ka ipu ana i ka māka a hui pū.
ʻO ka hopena maʻamau o ka potassium iodate, 10.06mg/L: E lawe i 10.0ml o ka solution stock (4.1) i loko o kahi pahu volumetric 1000ml, e hoʻohui i kahi 1g o ka potassium iodide (4.5), e hoʻohui i ka wai e hoʻoheheʻe i ka māka, a hui. E hoʻomākaukau i ka lā hoʻohana i loko o ka hue ʻeleʻele. ʻO 1.00ml o kēia hoʻonā maʻamau he 10.06μg KIO3, ʻo ia ka mea like me 1.00mg/L chlorine i loaʻa.
Phosphate buffer: E hoʻoheheʻe i 24g anhydrous disodium hydrogen phosphate a me 46g anhydrous potassium dihydrogen phosphate i loko o ka wai i hoʻoheheʻe ʻia, a laila hui i loko o 100ml o ka wai me ka 800mg EDTA disodium paʻakai i hoʻoheheʻe ʻia. E hoʻoheheʻe me ka wai i hoʻoheheʻe ʻia i 1L, e hoʻohui i ka 20mg mercuric chloride a i ʻole 2 kulu o toluene e pale ai i ka ulu ʻana o ka pala. ʻO ka hoʻohui ʻana i ka 20 mg o ka mercuric chloride hiki ke hoʻopau i ke keʻakeʻa ʻana o ka nui o ka iodide i waiho ʻia ke ana ʻana i ka chlorine manuahi. (E hoʻomaopopo: He mea ʻawaʻawa ka Mercury chloride, mālama me ka akahele a pale i ka ʻai ʻana)
N,N-diethyl-p-phenylenediamine (DPD) Hōʻike: E hoʻoheheʻe i ka 1.5g DPD sulfate pentahydrate a i ʻole 1.1g anhydrous DPD sulfate i loko o ka wai chlorine-free distilled i loaʻa ka 8ml1+3 sulfuric acid a me 200mg EDTA, ka paʻakai disodium. i loko o ka ʻōmole aniani ʻeleʻele, a mālama i kahi pouli. I ka pau ʻana o ka mea hōʻike, pono e hoʻoponopono hou ʻia. E nānā mau i ka waiwai absorbance o nā hāpana hakahaka,
Inā ʻoi aku ka nui o ka absorbance o ka blank ma 515nm ma mua o 0.002/cm, pono e haʻalele ka hoʻoponopono hou ʻana.
Potassium iodide (KI crystal)
Sodium arsenite solution: E hoʻoheheʻe i ka 5.0g NaAsO2 i ka wai i hoʻoheheʻe ʻia a hoʻoheheʻe ʻia i 1 lita. Nānā: He mea ʻawaʻawa ʻo NaAsO2, pale i ka ʻai ʻana!
Thioacetamide solution: E hoʻoheheʻe i ka 125 mg o ka thioacetamide i loko o 100 ml o ka wai hoʻoheheʻe.
Glycine solution: E hoʻoheheʻe i 20g glycine i loko o ka wai chlorine-free a dilute i 100ml. E kūʻai i ka hau. Pono e hoʻohui hou ʻia i ka wā e hiki mai ana ka turbidity.
Pane ʻakika Sulfuric (e pili ana i 1mol/L): E hoʻoheheʻe i 5.4ml H2SO4 paʻa i loko o 100ml wai hoʻoheheʻe.
ʻO ka solution sodium hydroxide (ma kahi o 2mol/L): Kauona i 8g NaOH a hoʻoheheʻe ʻia i loko o 100ml wai maʻemaʻe.
ʻAha hoʻolāʻau (hana).
I ka pūʻulu o 50 colorimetric paipu, e hoʻohui i 0.0, 0.25, 0.50, 1.50, 2.50, 3.75, 5.00, 10.00ml o ka potassium iodate solution maʻamau, e hoʻohui i kahi 1g o ka potassium iodide a me 0.5ml o ka solution sulfuric acid. kū no 2 mau minuke, a laila hoʻohui i ka 0.5ml sodium hydroxide solution a hoʻoheheʻe i ka māka. ʻO nā haʻahaʻa i loko o kēlā me kēia omole ua like ia me 0.00, 0.05, 0.10, 0.30, 0.50, 0.75, 1.00, a me 2.00 mg/L o ka chlorine i loaʻa. E hoʻohui i 2.5ml o ka phosphate buffer a me 2.5ml o ka DPD indicator solution, hui maikaʻi, a koke (i loko o 2 mau minuke) e ana i ka absorbance ma 515nm me ka hoʻohana ʻana i kahi cuvette 1-inch. E kaha i ka pihi ma'amau a e huli i ka hoohalike regression.
Nā ʻanuʻu hoʻoholo
Chlorine dioxide: E hoʻohui i 1ml o ka glycine solution i ka 50ml o ka wai hāpana a hui, a laila hoʻohui i 2.5ml o ka phosphate buffer a me 2.5ml o ka DPD indicator solution, hui maikaʻi, a ana koke i ka absorbance (i loko o 2 mau minuke) (ʻo G ka heluhelu).
Chlorine dioxide a me ka chlorine manuahi: E lawe i kahi laʻana wai 50ml hou, hoʻohui i 2.5ml phosphate buffer a me 2.5ml DPD indicator solution, hui maikaʻi, a ana koke i ka absorbance (i loko o 2 mau minuke) (ʻo ka heluhelu ʻana ʻo A).
7.3 Chlorine dioxide, chlorine manuahi a me ka chlorine i hui pū ʻia: E lawe i 50ml wai hou, hoʻohui i 1g o ka potassium iodide, hoʻohui i 2.5ml o ka phosphate buffer a me 2.5ml o ka solution indicator DPD, hui maikaʻi, a ana koke i ka absorbance (i loko 2 minuke) (C ka heluhelu ʻana).
Huina chlorine i loaʻa me ka noa chlorine dioxide, chlorite, noa koena chlorine a hui koena koena chlorine: Ma hope o ka loaʻaʻana o ka heluhelu C, hoʻohui i ka 0.5ml sulfuric acid solution i ka wai hāpana i loko o ka like colorimetric omole, a hui Ma hope o ku malie no 2 minuke, hoohui. 0.5 ml sodium hydroxide solution, hui a ana i ka absorbance koke (ʻo ka heluhelu ʻana ʻo D).
ClO2=1.9G (helu ʻia ʻo ClO2)
Loaʻa ka chlorine manuahi=AG
Hoʻohui ʻia ka chlorine i loaʻa = CA
Huina chlorine i loaʻa=D
Klorite=D-(C+4G)
Nā hopena o Manganese: ʻO ka mea hoʻopilikia nui loa i loaʻa i ka wai inu ʻo ia ka manganese oxide. Ma hope o ka hoʻohui ʻana i ka phosphate buffer (4.3), hoʻohui i ka 0.5 ~ 1.0ml sodium arsenite solution (4.6), a laila hoʻohui i ka hōʻailona DPD e ana i ka absorbance. E unuhi i keia heluhelu mai ka heluhelu A e hoopau
Wehe i ke keakea mai ka manganese oxide.
Ka hopena o ka mahana: Ma waena o nā ʻano analytical o kēia manawa e hiki ke hoʻokaʻawale i ka ClO2, ka chlorine manuahi a me ka chlorine i hui pū ʻia, me ka titration amperometric, ke ʻano iodometric mau, a me nā mea ʻē aʻe, e pili ana ka mahana i ka pololei o ka hoʻokaʻawale. Ke piʻi aʻe ka mahana, e hoʻoikaika ʻia ka chlorine hui ʻia (chloramine) e komo i ka hopena ma mua, e hopena i nā hopena kiʻekiʻe o ClO2, ʻoi aku ka chlorine manuahi. ʻO ke ala mua o ka hoʻomaluʻana,ʻo ia ka mālamaʻana i ka mahana. Ma kahi o 20 ° C, hiki iā ʻoe ke hoʻohui pū i ka DPD i ka hāpana wai a hui pū ʻia, a laila hoʻohui koke i ka 0.5ml thioacetamide solution (4.7) e hoʻōki i ka hui ʻana o ke koena chlorine (chloramine) mai DPD. Pane.
Ka hopena o ka manawa colorimetric: Ma kekahi ʻaoʻao, ʻaʻole paʻa ke kala ʻulaʻula i hana ʻia e ClO2 a me DPD. ʻO ka ʻeleʻele ke kala, ʻoi aku ka wikiwiki o ka mae. Ma ka ʻaoʻao ʻē aʻe, ʻoiai ua hui pū ʻia ka hopena buffer phosphate a me ka hōʻailona DPD i ka manawa, e mae nō hoʻi lākou. Hoʻopuka i kahi kala ʻulaʻula wahaheʻe, a ua hōʻike ʻia ka ʻike ʻo kēia ʻano paʻa ʻole o ka waihoʻoluʻu i ka manawa ke kumu nui o ka hōʻemi ʻana i ka pololei ʻikepili. No laila, ʻo ka wikiwiki ʻana i kēlā me kēia ʻanuʻu hana ʻoiai ke kāohi ʻana i ka standardization o ka manawa i hoʻohana ʻia i kēlā me kēia ʻanuʻu he mea koʻikoʻi ia i ka hoʻomaikaʻi ʻana i ka pololei. Wahi a ka ʻike: hiki ke kūpaʻa ka ulu ʻana o ke kala ma lalo o 0.5 mg / L no kahi o 10 a 20 mau minuke, ʻo ka hoʻomohala ʻana o ke kala ma kahi ʻano o 2.0 mg / L hiki ke paʻa wale no kahi o 3 a 5 mau minuke, a ʻo ka ʻO ka hoʻomohala ʻana o ka kala ma kahi ʻano ma luna o 5.0 mg/L e paʻa no ka liʻiliʻi ma mua o 1 mau minuke.
ʻO kaLH-P3CLOHāʻawi ʻia e Lianhua i kēia manawa he mea lawe limamika chlorine koenae pili ana i ke ʻano photometric DPD.
Ua hoʻonohonoho mua ka mea hoʻoponopono i ka lōʻihi nalu a me ka pihi. Pono ʻoe e hoʻohui i nā reagents a hana i ka colorimetry e kiʻi koke i nā hopena o ke koena chlorine, ke koena chlorine a me ka chlorine dioxide i loko o ka wai. Kākoʻo pū ia i ka lako mana pākaukau a me ka lako mana o loko, e maʻalahi ai ka hoʻohana ʻana inā ma waho a i ʻole ka hale hana.