含铅离子模拟废水沉淀处理理论分析及产物表征
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2020-04-28 21:56:36
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含铅离子模拟废水沉淀处理理论分析及产物表征①FrancisRuzagilizaInnocent,李新颖,陈泉源(东华大学环境科学与工程学院,上海201620)摘要:采用氢氧化钙、碳酸钠和硫化钠处理含铅废水,在测定铅离子浓度、pH值、ζ电位、上清液浊度等指标的基础上,结合溶液化学平衡分析及沉淀产物结构表征,探讨了沉淀剂用量对铅离子去除率的影响及沉淀剂作用机理。研究结果表明:氢氧化钙用量为理论计算量的2.5倍时,铅离子去除率达到最高值,为76.10%;碳酸钠用量为理论计算量的1.5倍时,铅离子去除率达到最高值,为99.80%;硫化钠用量为理论计算量的1.5倍时,铅离子去除率达到最高值,为99.70%。尽管硫化铅溶度积很小,而铅离子去除率比理论值低,其原因可能是溶液饱和度过高,某些沉淀物直径小于0.45μm,从而透过滤膜所致。X射线衍射和热重分析表明,氢氧化钙与含铅废水作用生成的沉淀物为PbO和Pb5O8;碳酸钠与含铅废水作用生成的沉淀物为PbCO3;而硫化钠与含铅废水作用生成的沉淀物为PbS,PbSO4和Pb10(CO3)6(OH)6O,这对污泥处理处置以及回收利用有指导意义。关键词:废水处理;铅;沉淀;ζ电位;污泥中图分类号:X703文献标识码:A文章编号:0253-6099(2011)06-0082-06PrecipitationofSynthesizedWastewaterContainingLeadIonsandCharacterizationofPrecipitationProductsFrancisRuzagilizaInnocent,LIXin⁃ying,ChenQuan⁃yuan(SchoolofEnvironmentalScienceandEngineering,DonghuaUniversity,Shanghai201620,China)Abstract:Calciumhydroxide,sodiumcarbonateandsodiumsulfidewereusedasprecipitantstoremoveleadionsfromsynthesizedwastewater.Basedonmeasurementsofconcentration,pH,ζ⁃potentialandsupernatantturbidityofleadions,theinfluenceofprecipitantdosageonleadionsremovals,aswellasthereactionmechanismswereexaminedwithsolutionchemicalequilibriumcalculationsandcharacterizationofprecipitationproducts.Resultsshowthattheremovalrateofleadionmaximallyreaches76.10%asthedosageofcalciumhydroxidebeing2.5timesasmuchasthetheoreti⁃calcalculations.Ascompared,itmaximallyreaches99.80%and99.70%,respectively,asthedosageofsodiumcar⁃bonateandsodiumsulfidebeing1.5timesand2.5times,respectively,asmuchasthetheoreticalcalculations.ThesolubilityproductofPbSisverylow,buttheremovalrateofleadionislowerthantheoreticalvalue,becausesomepre⁃cipitantwithparticlesizelessthan0.45μmpenetratedthroughthefiltrationmembraneduetoahighersaturation.Re⁃sultsfromX⁃raydiffractionandthermogravimetricanalysisshowedthatcalciumhydroxidereactingwithlead⁃containingwastewaterresultedintheprecipitantofPbOandPb5O8,sodiumcarbonatereactingwithlead⁃containingwastewaterre⁃sultedintheprecipitantofPbCO3,andsodiumsulfidereactingwithlead⁃containingwastewaterresultedintheprec
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