Cov cuab yeej tseem ceeb thiab cov tshuaj reagents rau hluav taws xob cua sov raj

Cov cuab yeej tseem ceeb thiab cov tshuaj reagents rau hluav taws xob cua sov raj

1 Kev sim ib feem

Cov dej khib nyiab electroplating siv hauv qhov kev sim no tau muab los ntawm Guanghui Electroplating Cog hauv Changzhou City, Jiangsu Province, nrog pH =1.75, tag nrho Cr 59 mg / L, thiab Cr6 ntxiv 36.8 mg / L

1.1 Main twj thiab reagents

Khoom siv: NovAA300 atomic absorption spectrophotometer, Shimadzu Corporation, Nyiv; Microfiltration membrane Cheebtsam, Tianjin Tianmeng tuam txhab; A6410 rau qhov txuas tov khoom, Wuhan Meiyu Company

Reagents: ferrous sulfate heptahydrate, potassium permanganate, diphenylcarbazide, thiab lwm yam., Shanghai Chemical Reagent Factory No. 3, analytical pure

Kev sim dej khib nyiab: Ib qho simulated chromium uas muaj cov dej khib nyiab electroplating nrog qhov loj ntawm 500 mg / L tau npaj siv K2Cr2O7. Nws tuaj yeem diluted kom tsim nyog raws li kev sim xav tau ua ntej siv

1.2 Cov ntsiab lus sim

Kev txiav txim siab ntawm qhov pom zoo, pH, thawj zaug concentration, thiab lwm yam rau FeSO4 txo thiab nag lossis daus ntawm Cr hauv dej khib nyiab; Txiav txim siab qhov zoo tshaj plaws aeration txaus tus nqi ntawm microfiltration membrane; Txhawm rau tshawb xyuas cov txiaj ntsig kev kho mob ntawm cov txheej txheem ua ke ntawm cov tshuaj nag lossis daus thiab microfiltration membrane ntawm cov chromium tiag tiag uas muaj cov dej khib nyiab electroplating. Hauv kev sim, qhov kev tshem tawm ntawm Cr tau txiav txim siab los ntawm kev ntsuas cov kev hloov pauv hauv cov ntsiab lus ntawm Cr6 ntxiv thiab tag nrho Cr hauv cov tshuaj ua ntej thiab tom qab kho. Kev ntsuas ntawm Cr6 plus tau ua tiav siv txoj kev diphenylcarbazide, thaum ntsuas tag nrho Cr tau ua tiav siv atomic absorption spectrophotometric.

Ua ntej, raws li kev sim orthogonal, qhov kwv yees qhov kev pom zoo rau cov dej nag tau txiav txim siab: qhov loj ntawm FeSO4 yog 2500 mg / L, txo pH yog 5, nag lossis daus pH yog 10, thiab thawj qhov loj ntawm chromium hauv electroplating dej khib nyiab. yog 150 mg/L. Tom qab ntawd, cov xwm txheej sim tau hloov pauv raws li qhov yuav tsum tau ua, thiab cov txiaj ntsig ntawm ntau yam ntawm cov txiaj ntsig kev kho mob tau tshawb xyuas

Txhawm rau hloov tag nrho Cr6 ntxiv rau hauv cov qauv tshuaj rau Cr3 ntxiv, qhov kev xav tau yog m (FeSO4.7H2O): m (Cr6 ntxiv)=16:1, tab sis qhov sib ntxiv ntawm FeSO4.7H2O yuav tsum siab tshaj qhov theoretical tus nqi [4]. Hauv qhov kev sim no, thaum m (FeSO4.7H2O): m (Cr6 ntxiv)=20:1, tus nqi ntawm Cr3 ntxiv yuav tsis nce ntxiv lawm. Yog li, nws tuaj yeem txiav txim siab tias qhov tsim nyog m (FeSO4.7H2O): m (Cr6 ntxiv) =20: 1

2.2 Cov nyhuv ntawm pH ntawm Txo Cr6 ntxiv

Raws li alkaline tej yam kev mob, Cr yog hloov los ntawm Cr2O72- mus rau CrO42-, uas zoo heev tsis muaj zog nws oxidizing muaj peev xwm. Yog li ntawd, qhov txo cov tshuaj tiv thaiv ib puag ncig yuav tsum ua ntej acidic [5]

Fix m (FeSO4 · 7H2O): m (Cr6+)=20:1, change the pH of the solution to determine the effect of pH on the reduction of Cr6+. Experimental observation shows that when pH ≈ 1.0, the wastewater appears light green and begins to generate Cr3+; When the pH is between 2.0 and 4.0, the wastewater appears yellow with a small amount of precipitation generated, resulting in a small amount of Fe (OH) 3 precipitation; When pH ≈ 4, about 98% of Cr6+is converted into Cr3+, and at this time, Cr3+undergoes hydrolysis precipitation, promoting the conversion of Cr6+; But when pH>5, cov ntsiab lus ntawm CrO42- nyob rau hauv cov tshuaj nce, uas yog hloov los ntawm Cr2O72- thiab tsis conducive rau oxidation thiab txo ntawm Cr6 ntxiv. Yog li, nws tuaj yeem txiav txim siab tias qhov kev txo qis pH hauv qhov kev sim no yuav tsum yog 3.5 ~ 5.0

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