磁种絮凝磁分离法处理含锌废水的研究黄自力

333Vol.33,No.320106JournalofWuhanUniversityofScienceandTechnologyJun.2010　　:2009-09-30　　:(59925412);(B200511004).　　:(1965-),,,.E-mail:[e-mail]-,,(,,430081):采用磁种絮凝-磁分离方法对模拟某锌盐制造企业的排放废水进行处理,研究了废水pH值对其Zn2+去除效果的影响、絮凝剂聚丙烯酰胺(PAM)和磁种(Fe3O4)对氢氧化锌沉淀物沉降性能的影响以及外加磁场对磁种-氢氧化锌絮凝体沉降性能的影响。结果表明,有利于Zn2+沉淀的最佳废水pH值为9～12;PAM与磁种同时使用能改善Zn(OH)2的沉降性能;在外加磁场作用下,废水中的磁种-氢氧化锌絮凝体由于受到与重力方向一致的磁力,其沉降速度加快,污泥压缩得更快、更实,上清液中锌的质量浓度降至0.83mg/L;磁性矾花絮凝体经硫酸溶液或氢氧化钠溶液浸泡后,过滤得到的磁种可循环使用,滤液中的锌可回收利用。:含锌废水;化学沉淀;磁种絮凝;磁分离:X703.1　　:A　　:1674-3644(2010)03-0323-04　　,。2070,,,,、[1]。。,,;,,,[2-6]。,Zn2+,-,GB18918—2002(1mg/L),。1　1.1　,10%10%pH,,2h,,Zn2+pH。1.2　-1000mg/L,pH10,(10μmFe3O4)、(PAM)、(Fe3O4)PAM。。1.3　-pHZn2+,(Fe3O4)PAM,,。,10%10%pH,。,,,。1.4　0.45μm,10%pH2;,1hGB7475—87。Z-800。2　2.1　pHZn2+ρ(Zn2+)100、200、300、400mg/20103L4,pHρ(Zn2+)1。pH6,;pH9～12,,;pH12,。1,pH9～12,Zn2+。,,1mg/L。2:①;②。Zn(Ⅱ)K1～K4(1)～(4),1　pHZn2+Fig.1EffectofpHvalueontheprecipitationofzinchy-dratesZn(OH)2(s)pH(5)～(19)。K1=[Zn(OH)+]/([Zn2+][OH-])=5×105(1)K2=[Zn(OH)2(l)]/([Zn(OH)+][OH-])=2.7×104(2)K3=[Zn(OH)-3]/([Zn(OH)2(l)][OH-])=1.26×104(3)K4=[Zn(OH)2-4]/([Zn(OH)-3][OH-])=1.82×10(4)(1)Zn(OH)2(s)=Zn2++2OH-(5)Ks=[Zn2+][OH-]2=7.1×10-18(6)-lg[Zn2+]=2pH-lgKs+2lgKw=2pH-10.85(7)(2)Zn(OH)2(s)=Zn(OH)++OH-(8)Ks1=[Zn(OH)+][OH-]=KsK1=3.55×10-12(9)-lg[Zn(OH)+]=pH-lgKs1+lgKw=pH-2.55(10)(3)Zn(OH)2(s)=Zn(OH)2(l)(11)Ks2=[Zn(OH)2(l)]=Ks1K2=9.585×10-8(12)-lg[Zn(OH)2(l)]=-lgKs2=7.02(13)(4)Zn(OH)2(s)+OH-=Zn(OH)-3(14)Ks3=[Zn(OH)-3]/[OH-]=Ks2K3=1.2×10-3(15)-lg[Zn(OH)-3]=-pH-lgKs3-lgKw=-pH+16.92(16)(5)Zn(OH)2(s)+2OH-=Zn(OH)2-4(17)Ks4=[Zn(OH)2-4]/[OH-]2=Ks3K4=2.18×10-2(18)-lg[Zn(OH)2-4]=-2pH-lgKs4-2lgKw=-2pH+29.66(19):Ks、Ks1、Ks2、Ks3、Ks4Zn(OH)2(s);Kw。(7)、(10)、(13)、(16)、(19),pH9～12,Zn(Ⅱ)1mg/L。1mg/L,。2.2　2。2,,240min,SV=37%,,360min,SV=35%;PAM,100min,,180min,(SV=46%),360min,SV=43%;PAM,(Fe3O4),120min,(SV=39%),360min,SV=28%;PAM(Fe3O4),,32420103,:-2　Fig.2SettlingcurvesofZn(OH)2underdifferentmagneticseedingflocculation30min(SV=40%),360min,SV=31%。:,,;PAM,、,PAM,;,,,。2.3　--3。3　-Fig.3Settlingcurvesofmagneticseed-Zn(OH)2aggrega-tionundermagneticfieldandnon-magneticfield3,,-,,;“”,、,8min,SV32%,28min,SV=29%。,,,0.83、0.90mg/L,1mg/L。Fm=χVHgradH(20):χ;V;H;gradH。(20),。Fe3O4,;,,,。2.4　Zn2+,,,Zn2+ZnO2-2。,99%。3000mg/L,,。3　(1)pH9～12,,;PAM、,。(2),-,,、,0.83mg/L。(3),,。[1]　,.[J].,2008(6):11-21.[2]　,,,.[J].,1998,15(2):13-18.[3]　,.[J].,2003(1):26-28.[4]　,.[J].,2000(1):42-43.[5]　,,,.[J].,2007,25(3):12-16.32520103[6]　EskandarpourA,SassaK,BandoY.Magneticre-movalofphosphatefromwastewaterusingschwetmannite[J].MaterialsTransactions,2006,47(7):1832-1837.Treatmentofzinc-containingwastewaterbymagneticseedingflocculationandmagneticseparationHuangZili,ChenZhihua,XiaMinghui(HubeiKeyLaboratoryforEfficientUtilizationandAgglomerationofMetallurgicMineralResources,WuhanUniversityofScienceandTechnology,Wuhan430081,China)Abstract:Thezinc-containingwastewaterwastreatedbymagneticseedingflocculationandmagneticseparation.First,theeffectofpHvalueontheprecipitationofZn2+ionandthatofflocculatant(PAM)andmagneticseed(Fe3O4)onthesettlementofZn(OH)2wereinvestigated.Secondly,acon-trastingtestofthesettlementofmagneticseed-Zn(OH)2aggregationinsideandoutsideadesignedmagneticfieldwascarriedout.TheresultsindicatethatthepHvaluebestforZn2+ionprecipitationisfrom9to12;thesettlementpropertiesofZn(OH)2canbeimprovedbythecombineduseofPAMandFe3O4;themagneticseed-Zn(OH)2aggregationsinkfasterandthesludgebecomesmoreeasilycom-pressedbecausethemagneticforceaccordswiththegravity.Undertheexternalmagneticfield,thesludgesettlementratiodeclinesto32%after8-minutesettlementandto29%after28-minutesettle-ment,andthezinccontentoftheupperclearliquidis0.83mg/L.ItisalsodemonstratedthattheFe3O4andZncanbeseparatedcompletelyandreusedafterthemagneticseed-Zn(OH)2aggregationissoakedwithsulfideacidorsodiumhydroxidesolutionandfiltered.Keywords:zinccontainingwastewater;chemicalprecipitation;magneticseedingflocculation;magnet-icseparation[　　]326