污水污泥中重金属去除方法研究

湖南大学硕士学位论文污水污泥中重金属去除方法研究姓名：黄玉娥申请学位级别：硕士专业：环境工程指导教师：刘云国20070425IIFe3+CTA[W1W2]20g·L-1W1Fe3+1.5g·L-1pH3.02CdCuZn82.5%70.9%89.0%W24.5g·L-1Fe3+pH3.19CdCuZn80.0%88.2%92.1%pHFe3+Fe3+CTACTAPbCdCuZn,0.2mol·L-1CTA24h,56%85.2%65%88.5%CTAIIIAbstractWiththedevelopmentofcityandincreaseoftreatmentratioofwastewater,alargeamountofsludgehasbeenproduced.Thesludgedirectlyenterintoenvironmentwillcausesecondarypollutiontowaters,air,soil.Landapplicationofsludgeonagriculturallands,forestanddisturbedlandswasconsideredabestmethodtotreatmunicipalsludge.Unfortunately,pollutantssuchastoxicorganiccompounds,heavymetalsandpathogensinthesludge,especiallyheavymetalslimititsuseonlandapplication.Now,themainproblemishowtoremoveorcontroltheheavymetalsinsludgeeffectivelyandeconomically.Theaimofthisstudyistolookforsomenewmethodswhichcanremoveheavymetalsfastandeffectivelyandarefriendlytoenvironment.Throughanalyzingthemechanismandfactorswhichaffecttheremovalofheavymetalsfromsludgebybioleachingandchemicalmethod,Inthisworktheferricsulfateandcitricacidwereusedtoremoveheavymetalsinsludge.Inthefirstexperiment,Theremovalofheavymetalsfromtwodifferentkindsofsewagesludge(W1W2)wasconductedbyusingferricsulfateatroomtemperatureandsludgesolidconcentrationis20g·L-1.Itwasfoundthattheadditionofferricsulfatetothesludgecausestheacidificationofthetestedsludgeandthedissolutionofheavymetalsfromthesludge.ForW1,thebestamountofferricionaddedwas1.5g·L-1withalowpHvalue3.02andhighremovalpercentsofCdCuZnwhichareasfollows:82.5%70.9%89.0%respectively;whileforW2thebestamountofferricionis4.5g·L-1andthepHvaluesis3.19andtheremovalpercentsofheavymetals——CdCuZnare80.0%88.2%92.1%respectively.FerriciondissolvedCdCuZnmoreeffectivelythansulfuricacidatsamepHvalue.TheremovalpercentsofCd,CuandZnusingferricsulfatewasequivalenttothatbybioleachingandshortedtheexperimenttime.Inthesecondexperiment,CTAwasusedtotreatheavymetalsofsludge(W2).TheresultsindicatedthatbothCTAconcentrationandsludge-liquidratiohaveapositiverelationwiththeelutionquantityofheavymetals,whilejustattheearlyphaseofextraction,theextractingtimehasapositiverelationwiththeelutionquantity,withthetimeprolonging,thereisalittledecreaseinthequantityofextractedmetals.AndCTAcaneffectivelyextractPb,Cd,Cu,Znfromsewagesludge.Atroomtemperature,theremovepercentofPb,Cd,Cu,ZncanreachIV56%,85.2%,65%,88.5%,respectively,byextractingwith0.2mol·L-1CTAandasludge-liquidratio1:20.CTAcanextractnotonlyexchangeablemetals,adsorbedmetals,organicallyboundmetalsandmetalcarbonates,butalsosomemetalsulfides,andalittleresidualmetals.Keywords:Sewagesludge,Heavymetal,Citricacid,Ferricsulfate,ChemicalformI1______21120055060201060701000,NPK,,pH1.11.1.1.()CO2O2CH42[1]NPKCa60%-70%NP[23]90%75%-80%1.1.21.10.3%-0.5%()1%2%[4]2342.:(1):NH4+K+[5](2)::/[6]:;;;(3):NPNPN3P;(4):(5):50%-80%[7]1.21.2.170%20%10%A2/O[8]1.2.1.02-1.031.3-1.541.O-1.0051.O-1.011.01.01.03.500-30000.5%6%1.2.294%20%.Banerjee[9]10%-15%()()Latifoglu5[10],,,,,,[11]1.2.3,75%-85%,,,,[8]1.,[12]:,(40%)[13](CEC)1.1Tab1.1Watercontentofsludgeafterdehydratingbydifferentmethod%95-9770-8060-8045-8076-8680-8510-400-1061.31.3.1[14]199819991.3.260,,1.3.32-4[15]7,,,R.Khanbilvardi[16]30%()Okuno[17]100%1.3.4Ca,Mg,Cu,Zn,Fe40%-70%[18][19-22]NP[23]1.3.51/6-1/5[24-27](CH4)60%-70%[28][29][30-36][37-39]1000-11000.5%-1%8[40]1.3.6.1/[41-42]1.2Tab.1.2ThedisposalmethodofsewageinEuropeUnionState,USAandJapan(%)1830457-30428713193025216-31.9-62.75.444.8%31%10.5%13.7%1.410%-80%45%[152443-44][45-47][48-49][50-54]91.4.15g/cm345::1.2.3.4.105.6..7.8.1.4.21.HgHgCl2HgSHg3(PO4)2Hg[55]pHEhpH7HgpHHgEhHg2+HgSEhHgSHgSO4Hg2+Cl-Hg[56-57]2.Cr90%Cr(III)pHCr(VI)Cr(VI)Cr(III)11pHCr[58-59]3.Zn2+Zn(OH)+ZnCl+Zn(NO3)+[60]pHZnZnZn2+[61]4.CuCuCuCuCuCu[6062]CuCuCu[63]5.Pb(OH)2PbCO3Pb3(CO3)3Pb3(PO4)2PbSPb2+PbpHPb[6264]6.CdCdCl2CdCO3CdSpHEhpHEhCdS2-7.As5%-10%−34ASO[65]pHEhpH12EhpHEhEhEhEh[66]1.4.31.100a-200a2.3.[67-70]1.31.4.3131.2.[71-72]pHpH[73-75]3.pH1.3mg/kgPH6.5PH6.5Cd520Hg515Pb3001000Cr6001000As7575B1501503000300033Cu250500Zn5001000Ni10020014pH;[76-77]152GB4284-1984[78]:1.2.3.4.2.1()[79-82][83][84][85-86]2.1.1(Thiobacillusthiooxidans)(Thiobacillusferrooxidans)2.1.216EhpH[79-80]:1.(MS)2.14..2MSO2OMSidansthiooxTidansferrooxT+(2.1)2.1pH2.02.22.32.42.5:2Fe2++1/2O2+2H+=2Fe3++H2O(T.ferroxidans)(2.2)MS+2Fe3+=2Fe2++M2++S0()(2.3)2S0+3O2+2H2O=2H2SO4T.thiooxidans(2.4)H2SO4+M-sludge=2H-sludge+M2++SO42-(2.5)2(2.4)(2.5)2.1.3pHEh1.BlaisJFArrhenius17[87]:ln=lnAEa/RTAArrheniusRTEaTyagiRD[87]714212835pH2.0336240192120120h,42pH2.0302.pHpH.pH.pH.BlaisJF[88]:pH7.0-8.04.0-5.0pH1.0-2.0[89]Tyagi[90]pH=A+BlnpH=1dN/NdtNABpHpH[91].2.1pHTab.2.1TherelationbetweenremovalofmetalsandpHvalueZnNiCaCuCrPbpH5.965.14.93.83.2pH2.0(%)8050-8060-8060-8020-5015-4018pH2.1pH[92]3.EhEhEhEhpH[93]Eh[94]4.Tyagi[95]19()10d63%-75%39%-65%,pHpHSteekriskman[93]7-70g.L-1pHCrCdPbCuZn()NPMgKNPMgK5.()Fe2+6.5h-15h10h-25hFe2+[96-97]6.192.22.2Tab.2-2Efficiencyofheavymetalremovalandconditionsofbioleaching(%)CuZnMnCdCrNiPb/dT.FFeSO47H2O526278****0.75[96]I.D95*9897*92*5[80]I.D7880543972266[98]I.D7585*823170271.5-5[99