化学沉淀磁絮凝深度快速除磷的研究

321Vol.32,No.120092JournalofWuhanUniversityofScienceandTechnologyFeb.2009:2008-07-16:(59925412);(B200511004).:(1965-),,,.E-mail:[e-mail]-,,(,,430081):采用化学沉淀法研究Al2(SO4)3FeCl3CaCl2的药剂用量和pH值对除磷效果的影响,探讨非磁性悬浮物磁性接种的机理,并分析了铝铁钙的磷酸盐沉淀物由于加入磁种而变得易于沉降,特别是在磁场力作用下沉降速度加快的原因结果表明,Al2(SO4)3FeCl3CaCl2是磷酸根离子的有效沉淀剂,在适当的药剂投加量和pH值条件下,废水经过处理后,剩余磷的浓度小于0.5mg/L;生成的铝铁钙的磷酸盐沉淀物颗粒与Fe3O4颗粒在某一pH值下表面电性相反,易发生相互凝聚;磁性接种的铝铁钙的磷酸盐沉淀物不仅变得更重,而且在磁场中还受到与重力方向相同的磁场力作用:化学沉淀;除磷;磁絮凝;沉降:X703.1:A:1674-3644(2009)01-0102-04,,;,,,6mg/L,(GB18918)2002)0.5mg/L,[1-3]()()(),,0.1mg/L[4-7],,,,,[8](),Fe3O4,,AlPO411.1(1)Na3PO4/0,10mg/LAl2(SO4)3FeCl3CaCl2,10%/0,20min,3h,1Lm,(2),(100mg/L)/0,n(Al)/n(P)2B1Al2(SO4)3,pH6.5,20min,PAM(),,,(3)0.2T,,Fe3O4,10Lm1.2Zeta(1)(2)Zeta(JS94H)Fe3O4pHZeta20091,:-22.111,Al2(SO4)3FeCl3CaCl20.130.080.12g/L,,/0,,,Al2(SO4)3FeCl3CaCl20.130.080.12g/L,n(Al)/n(P)n(Fe)/n(P)n(Ca)/n(P)2B11.6B12B1,,95%1Fig.1EffectofprecipitatingagentsonPremoval2.2pHn(Al)/n(P)n(Fe)/n(P)n(Ca)/n(P)2B11.6B12B1,2pH2,Al2(SO4)3FeCl3CaCl2,pH4.5~8.05.39.5~12.02pHFig.2EffectofpHvalueonPremoval,Al2(SO4)3,pHpH=4.5~7.0,AlPO4AlPO4:AlPO4=Al3++PO3-4,KSP=10-21(1)Al3++OH-=AlOH2+,K1=109.01(2)AlOH2++OH-=Al(OH)+2,K2=109.69(3)Al(OH)+2+OH-=Al(OH)3(aq),K3=108.3(4)Al(OH)3+OH-=Al(OH)-4,K4=106(5)PO3-4+H+=HPO2-4,KH1=1012.35(6)HPO2-4+H+=H2PO-4,KH2=107.20(7)H2PO-4+H+=H3PO4,KH3=102.15(8):KcSP=[Al3+]T[PO3-4]T=[Al3+]AAl[PO3-4]AP=[Al3+][PO3-4]AAlAP=KSPAAlAP(9):APAAlS:S=KcSP(10)AAl=1+K1[OH-]+K1K2[OH-]2+K1K2K3[OH-]3+K1K2K3K4[OH-]4=1+109.01[OH-]+1018.70[OH-]2+1027[OH-]3+1033[OH-]4(11)AP=1+KH1[H+]+KH1KH2[H+]2+KH1KH2KH3[H+]3=1+1012.35[H+]+1019.55[H+]2+1021.7[H+]3(12)AlPO4pH(9)~(12),33,pH4.0~7.0,AlPO43pHFig.3RelationshipbetweenpHvalueandsolubilitylog-arithm2.3ZetapH4Fe3O410320091pHZeta4,Fe3O4pH=6.4pH=4.0pH=5.0,pH2.0Zeta,Fe3O4pH=4.0~6.4pH6.4pH=5.0~6.4,,4ZetapHFig.4RelationshipbetweenpHvalueandzetapotentialZeta?30mV[9],pH,pH=4.0~8.0pH8.0pH=4.0~8.0,,,,2.4Fe3O4,/0100mg/L,n(Al)/n(P)2B1Al2(SO4)3,pH6.5,PAM,55,PAM,,30min30%,80min;120min30%,200min,,,,PAM5Fig.5Relationshipbetweensettlingtimeandsludgesettlingratio2.5/0100mg/L,n(Al)/n(P)2B1Al2(SO4)3,pH6.5,0.1g/L,0.2T,,;,,3min30%,6min,(),[10],,2F=Fg-Fr,M=V(D-Q)g/(3PGd)(13):Fg,N;Fr,N;V,m3;D,kg/m3;Q(),kg/m3;g,m/s2;G,N/(m2#s);M,m/s;d,m,,,,2F=Fm+Fg-Fr,Mc=(V(D-Q)g+VVHgradH)/(3PGd)(14):Fm,N;V,m3/kg;H,A/m;gradH,A/m2(13)(14),McM,,McM,3(1)Al2(SO4)3FeCl3CaCl210420091,:-,pH,,0.5mg/L,Al2(SO4)3n(Al)/n(P)2B1,pH4.5~7.5;FeCl3n(Fe)/n(P)1.6B1,pH5.0~5.5;CaCl2n(Ca)/n(P)2B1,pH9.0~12.0(2)Fe3O4pH=4.0~6.4pH6.4pH=5.0~6.4,,(3),,,[1],.-[J].,1999,19(4):5-9.[2].[J].,1999,1(1):1-5.[3]RaoYSurampalli,ShankhaKBanerji,CharlesJPycha,etal.Phosphorusremovalinponds[J].WaterScienceandTechnology,1995,31(12):331-339.[4],,.[J].,2003,23(5):3-9.[5],.[J].,2004,30(5):2-10.[6],,.[J].,2004,24(2):4-8.[7]DMWeaver,GSPRitchie.Phosphorusremovalfrompiggeryeffluentsofvaryingqualityusinglimeandphysico-chemicaltreatmentmethods[J].Env-ironmentalPollution,1994,84(3):237-244.[8]HuangZili,HuYuehua,XuJin,etal.Removalofphosphatefrommunicipalsewagebyhighgradientmagneticseparation[J].JournalofCentralSouthUniversityofTechnology,2004(4):391-394.[9],.[M].:,1992:167.[10],.[J].,1997,34(3):50-55.Furtherandfasterremovalofphosphorusbychemicalprecipitation-magneticflocculationHuangZili,XiaoJingjing,LiMi(CollegeofResourcesandEnvironmentalEngineering,WuhanUniversityofScienceandTechnology,Wuhan430081,China)Abstract:TheeffectsofAl2(SO4)3,FeCl3andCaCl2dosagesandpHvalueofchemicalprecipitationonphosphorusremovalarestudied.Themechanismofmagneticseedingfornonmagneticsuspendedsub-stancesisdiscussedbymeasuringthezetapotentialofFe3O4andphosphatesofaluminum,ironandcalcium.Itisfoundthatthephosphatesofaluminum,ironandcalciumbecomemoreeasilysettledbe-causeofmagneticseeding,especiallytheactionofmagneticfield.ItisalsofoundthatAl2(SO4)3,FeCl3andCaCl2areefficientprecipitatorsofphosphateion,andtheresidualphosphoruscontentoftreatedwastewaterislessthan0.5mg/LunderproperdosageandpHvalue.Thegranulesofphos-phatesofaluminum,ironandcalciumagglomerateeasilywiththoseofFe3O4becauseoftheirreversesurfacepotentials.Themagneticseededprecipitatesofthephosphatesnotonlybecomemoreweightybutalsosufferfromamagneticforcewhosedirectionaccordswiththegravity.Keywords:chemicalprecipitation;phosphorusremoval;magneticflocculation;settling[]105