Kev tswj cov tshuaj tiv thaiv kab mob hauv Cyanide Wastewater Treatment

Introduction

Cyanide - muaj cov dej khib nyiab yog tsim los ntawm ntau yam kev lag luam xws li hlau plating, steel rooj plaub - hardening, thiab kub thiab nyiaj ore refining. Vim lub siab toxicity ntawm cyanide, uas tuaj yeem ua rau tuag taus rau cov kab mob uas muaj sia nyob txawm tias muaj qhov tsawg, kev kho kom zoo ntawm cov dej khib nyiab yog qhov tseem ceeb tshaj plaws. Ib qho tseem ceeb ntawm kev ua haujlwm zoo kev kho dej khib nyiab cyanide yog qhov tseeb tswj ntawm cov tshuaj tiv thaiv kab mob. Kab lus no yuav delve rau hauv cov tshuaj tiv thaiv tseem ceeb thiab yuav ua li cas tswj lawv thaum kho cyanide - muaj cov dej khib nyiab.

pH tswj

Qhov tseem ceeb hauv cov txheej txheem kev kho mob sib txawv

1.Alkaline Chlorination txheej txheem

• Alkaline chlorination yog ib txoj hauv kev rau kev kho dej khib nyiab cyanide, thiab kev tswj pH ua lub luag haujlwm tseem ceeb. Cov tshuaj tiv thaiv kev kho mob tshwm sim hauv ob kauj ruam. Hauv thawj theem, cyanide yog oxidized rau cyanate los ntawm sodium hypochlorite los yog kev sib xyaw ntawm cov roj chlorine thiab sodium hydroxide. Qhov zoo tshaj pH ntau rau thawj zaug - theem oxidation feem ntau yog nyob nruab nrab ntawm 10 thiab 11. Yog tias pH qis dhau, tig acidic, cov tshuaj tiv thaiv yuav tsim cov tshuaj lom cyanogen chloride, uas ua rau muaj kev phom sij loj. Piv txwv li, thaum pH poob qis dua 8. qhov teeb meem no los ntawm - cov khoom tuaj yeem tsim. Ntawm qhov tod tes, yog tias pH siab dhau lawm, cov tshuaj tiv thaiv yuav txo qis heev. High pH qhov tseem ceeb tuaj yeem cuam tshuam rau kev solubility thiab reactivity ntawm cov reactants, ua rau cov txheej txheem oxidation tsawg dua.

2.Hydrogen Peroxide Method

• Nyob rau hauv hydrogen peroxide - raws li kev kho mob ntawm cyanide cov dej khib nyiab, qhov zoo tshaj pH ntau feem ntau nyob nruab nrab ntawm 9 thiab 11. Nyob rau hauv txoj kev no, hydrogen peroxide decomposes nyob rau hauv lub xub ntiag ntawm ib tug catalyst (xws li hlau ntsev) los tsim cov reactive hydroxyl radicals uas oxidize lub cyanide. Cov pH nyob rau hauv qhov ntau no txhawb kev decomposition ntawm hydrogen peroxide thiab tsim cov radicals tseem ceeb. Yog tias pH nyob sab nraud qhov no, qhov decomposition ntawm hydrogen peroxide yuav inhibited, txo cov oxidation tag nrho.

3. Biodegradation txheej txheem

• Rau biodegradation ntawm cyanide - muaj cov dej khib nyiab, qhov twg cov kab mob ua kom cov kab mob ua kom tsis zoo, pH yuav tsum tau khaws cia ntawm 6.5 txog 8.5. Cov kab mob microorganisms muaj qhov zoo tshaj pH ntau rau lawv cov haujlwm metabolic. Yog tias pH yog acidic lossis alkaline dhau lawm, nws tuaj yeem ua rau cov enzymes koom nrog hauv cyanide - degrading metabolic pathways ntawm cov kab mob. Piv txwv li, yog tias pH poob qis dua 6.5. ntau cyanide - cov kab mob degrading yuav muaj kev txo qis hauv lawv txoj kev loj hlob thiab cyanide - degrading peev xwm.

Cov txheej txheem rau kev hloov pH

Txhawm rau tswj cov pH, cov khoom tsim nyog acidic lossis alkaline ntxiv rau cov dej khib nyiab. Cov kua qaub uas siv xws li sulfuric acid thiab hydrochloric acid, thaum cov alkalis feem ntau yog sodium hydroxide thiab calcium hydroxide. Tus nqi ntawm cov kua qaub los yog alkali ntxiv yog xam raws li qhov pib pH ntawm cov dej khib nyiab thiab lub hom phiaj pH rau cov txheej txheem kho tshwj xeeb. Kev ntsuas pH meej yog ua los ntawm kev siv pH sensors, thiab kev siv tshuaj tua kab mob tuaj yeem siv los ntxiv cov tshuaj uas xav tau kom raug.

kub Control

Kev cuam tshuam rau tus nqi tshuaj tiv thaiv

1.Alkaline Chlorination thiab Hydrogen Peroxide Methods

• Feem ntau, qhov kub thiab txias tuaj yeem ua kom cov tshuaj tiv thaiv kab mob hauv ob qho tib si alkaline chlorination thiab hydrogen peroxide - raws li kev kho mob. Txawm li cas los xij, qhov kub thiab txias yuav tsum tau ua tib zoo tswj. Nyob rau hauv alkaline chlorination, qhov zoo tshaj plaws kub yog nyob ib ncig ntawm 20 - 30 ° C. Yog tias qhov kub thiab txias qis dhau, cov tshuaj tiv thaiv yuav qeeb, ua rau tsis tiav oxidation ntawm cyanide. Piv txwv li, ntawm qhov kub siab tshaj 15 ° C, cov tshuaj tiv thaiv ntawm cyanide thiab sodium hypochlorite yuav siv sij hawm ntev heev kom ncav cuag. Ntawm qhov tod tes, yog tias qhov kub thiab txias heev, nyob rau hauv cov ntaub ntawv ntawm alkaline chlorination, chlorine roj yuav khiav tawm ntawm cov tshuaj, txo cov kev ua tau zoo ntawm oxidizing tus neeg sawv cev. Nyob rau hauv txoj kev hydrogen peroxide, qhov kub siab tshaj 35 ° C tuaj yeem ua rau qhov kev puas tsuaj sai ntawm hydrogen peroxide, ua rau muaj cov pa roj carbon monoxide es tsis txhob xav tau hydroxyl radicals rau cyanide oxidation.

2. Biodegradation txheej txheem

• Nyob rau hauv biodegradation ntawm cyanide - muaj cov dej khib nyiab, qhov zoo tshaj plaws kub ntau rau feem ntau cyanide - degrading microorganisms yog 20 - 35 ° C. Kub sab nraum qhov ntau no tuaj yeem cuam tshuam loj rau kev ua haujlwm ntawm cov kab mob. Thaum qhov kub thiab txias (qis dua 20 ° C), tus nqi metabolic ntawm cov kab mob qeeb zuj zus, thiab lawv yuav tsis tuaj yeem ua rau cov cyanide zoo. Qhov kub siab (siab tshaj 35 ° C) tuaj yeem ua rau cov cell membranes thiab cov enzymes ntawm cov kab mob ua kom puas, ua rau cell tuag thiab poob ntawm lawv cov cyanide - degrading peev xwm.

Cov txheej txheem ntsuas kub

Txhawm rau tswj qhov kub thiab txias, cua sov lossis cua txias tuaj yeem ntsia tau rau hauv cov dej khib nyiab kho reactors. Rau cua sov, chav - raws li cua sov tshuab lossis hluav taws xob cua sov tuaj yeem siv tau. Hauv kev ua kom txias, dej - txias cua sov los yog cua - txias condensers tuaj yeem ua haujlwm. Kev ntsuas kub tsis tu ncua yog siv cov ntsuas kub ntsuas, thiab cov cua sov lossis cua txias tau hloov kho raws li qhov ntsuas kub ntawm qhov zoo tshaj plaws rau cov txheej txheem kho.

Oxidant Dosage Control

Kev Txiav Txim Siab Zoo

1.Alkaline Chlorination

• Hauv alkaline chlorination, tus nqi ntawm oxidant (sodium hypochlorite lossis chlorine gas) xav tau yog xam raws li cov tshuaj tiv thaiv stoichiometry nrog cyanide. Hauv kev xyaum, qhov ntau tshaj ntawm oxidant, feem ntau 10 - 20% ntau dua li qhov theoretical, feem ntau yog ntxiv. Qhov no yog txhawm rau ua kom tiav oxidation ntawm cyanide, vim tias tej zaum yuav muaj lwm yam khoom hauv cov dej khib nyiab uas tuaj yeem haus cov oxidant. Yog tias cov tshuaj oxidant tsawg dhau lawm, cyanide yuav tsis raug oxidized kiag li, thiab cov dej khib nyiab kho yuav tseem muaj cov tshuaj lom cyanide siab. Ntawm qhov tod tes, yog tias qhov ntau npaum li cas, nws tsis yog tsuas yog nce tus nqi kho mob xwb tab sis kuj tuaj yeem ua rau muaj qhov tsis xav tau los ntawm - cov khoom lag luam, xws li cov tshuaj tua kab mob tsis zoo los ntawm - cov khoom lag luam thaum cov tshuaj chlorine ntau dhau nrog lwm cov organic teeb meem hauv cov dej khib nyiab.

2.Hydrogen Peroxide Method

• Hauv txoj kev kho hydrogen peroxide, qhov kev pom zoo ntawm hydrogen peroxide yog txiav txim siab los ntawm kev kuaj sim. Qhov ntau npaum li cas nyob ntawm yam xws li thawj zaug cyanide concentration hauv cov dej khib nyiab, muaj lwm yam cuam tshuam, thiab hom catalyst siv. Zoo ib yam li alkaline chlorination, ib qho tsis txaus ntawm hydrogen peroxide yuav ua rau tsis tiav cyanide oxidation. Txawm li cas los xij, qhov ntau dhau ntawm hydrogen peroxide tuaj yeem ua rau decomposition ntawm hydroxyl radicals generated, txo cov kev kho mob tag nrho thiab nce nqi.

Dosage Control Equipment

Txhawm rau kom tswj tau cov tshuaj oxidant kom raug, cov twj ntsuas ntsuas feem ntau yog siv. Cov twj no tuaj yeem xa cov ntim uas xav tau ntawm cov tshuaj oxidant rau hauv cov dej khib nyiab kho reactor. Kev tswj hwm lub tshuab tuaj yeem ua ke nrog cov ntsuas ntsuas, uas kho cov tshuaj raws li lub sijhawm saib xyuas ntawm cyanide concentration hauv cov dej khib nyiab lossis kev nce qib ntawm cov tshuaj tiv thaiv oxidation (xws li los ntawm kev ntsuas ORP, uas yuav tau tham tom qab).

Oxidation - Txo Qhov Muaj Peev Xwm (ORP) Tswj

Lub luag haujlwm hauv Kev Saib Xyuas Kev Tshawb Fawb Kev Tshawb Fawb

1.Alkaline Chlorination

• Hauv cov txheej txheem alkaline chlorination, kev saib xyuas ORP yog qhov tseem ceeb rau kev taug qab qhov kev nce qib ntawm cov tshuaj tiv thaiv oxidation. Raws li oxidation ntawm cyanide rau cyanate thiab tom qab ntawd ntxiv oxidation ntawm cyanate rau cov khoom tsis zoo tshwm sim, ORP tus nqi ntawm cov dej khib nyiab hloov. Thaum thawj theem oxidation ntawm cyanide rau cyanate, ORP feem ntau nce. Lub hom phiaj ORP rau theem no yog nyob ib ncig ntawm 300 - 500 mV (nyob ntawm seb cov tshuaj tiv thaiv tshwj xeeb). Thaum ORP mus txog qhov no, nws qhia tau hais tias thawj theem oxidation yog ze rau kev ua tiav. Hauv qhov thib ob - theem oxidation ntawm cyanate rau cov khoom tsis zoo, ORP nce ntxiv, thiab lub hom phiaj feem ntau yog nyob ib ncig ntawm 600 - 700 mV. Los ntawm kev saib xyuas ORP, cov neeg ua haujlwm tuaj yeem txiav txim siab thaum twg yuav tsum tsis txhob ntxiv cov oxidant, kom ntseeg tau tias cov tshuaj tiv thaiv tau ua tiav tsis dhau - oxidizing cov dej khib nyiab lossis khib nyiab oxidant.

2.Hydrogen Peroxide Method

• Hauv kev kho hydrogen peroxide - raws li kev kho mob, ORP kuj tseem ua haujlwm tseem ceeb ntawm cov tshuaj tiv thaiv kev nce qib. Thawj ORP ntawm cov cyanide - muaj cov dej khib nyiab yog qhov tsawg. Raws li hydrogen peroxide ntxiv thiab cov tshuaj tiv thaiv oxidation pib, ORP nce. Lub hom phiaj ORP ntau rau kev kho hydrogen peroxide ntawm cyanide cov dej khib nyiab feem ntau nyob ib ncig ntawm 400 - 500 mV. Thaum ORP ncav cuag tus nqi no, nws qhia tias cov cyanide tau zoo oxidized rau ib daim ntawv uas tsis muaj tshuaj lom.

ORP Saib Xyuas thiab Tswj Systems

ORP sensors yog siv los saib xyuas tus nqi ORP ntawm cov dej khib nyiab hauv kev kho reactor. Cov sensors no txuas nrog lub kaw lus tswj uas tuaj yeem ua haujlwm los kho qhov sib ntxiv ntawm cov oxidant. Piv txwv li, yog tias ORP nyob hauv qab ntawm lub hom phiaj, qhov kev tswj hwm tuaj yeem ua kom cov tshuaj oxidant (xws li hydrogen peroxide lossis sodium hypochlorite) ntxiv rau cov dej khib nyiab. Hloov pauv, yog tias ORP tshaj li lub hom phiaj, qhov kev tswj hwm tuaj yeem txo lossis nres cov oxidant ntxiv.

xaus

Kev tswj cov tshuaj tiv thaiv hauv kev kho cov dej khib nyiab cyanide yog qhov tseem ceeb rau kev ua kom tau txais txiaj ntsig zoo thiab kev nyab xeeb ntawm cov dej khib nyiab no. Kev tswj xyuas meej ntawm pH, qhov kub thiab txias, oxidant ntau npaum li cas, thiab ORP tuaj yeem xyuas kom meej tias cov txheej txheem kho tau zoo hloov cyanide rau hauv cov tshuaj tsis muaj tshuaj lom lossis tsis muaj tshuaj lom. Los ntawm kev ua tib zoo tswj cov kev mob tshwm sim no, kev lag luam tuaj yeem tsis tsuas yog ua tau raws li ib puag ncig cov cai, tab sis kuj txhim kho tus nqi - kev ua tau zoo ntawm lawv cov txheej txheem kev kho dej khib nyiab cyanide. Kev saib xyuas tsis tu ncua thiab kev hloov kho ntawm cov kev txwv no yog tsim nyog los hloov kho cov kev hloov pauv hauv cov dej khib nyiab thiab kev kho cov nroj tsuag kev ua haujlwm.