简介:Co,Ni,CrandVin25typicalsoilsofChinawerefractionatedintoexchangeable,carbonatebound(calcareoussoils),Mnoxidebound,organicallybound,amorphousFeoxidebound,crystallineFeoxideboundandresidualformsusingaseven-stepsequentialextractionprocedure,soastostudythedistributionofchemicalformsofthesemetalsaswellastheeffectsofsoilproipertiesonthedistribution.TheresultsshowedthatmostofsoilCo,Ni,CrandVwerepresentinresidualforms,andthedistributionratioaveraged48.2%forCo,53.0%forNi,81.5%forCrand68.7%forV.Thespeciationofheavymetalswasgreatlyinfluencedbysoilphysico-chemicalpropertiesandthechemistryofelements.Theresultsalsoindicatedthattherecoveryofmetalelementsbythesequentialextractionprocedurewassatisfactory,withtherelativedifferencebetweenthesumofsevenformsandthetotalcontentinsoilsaveraging9.5%forCo,12.8%forNi,6.6%forCrand7.2%forV.
简介:建立起HNO3-H2O2-HF体系微波消解前处理样品,利用电感耦合等离子体质谱(ICP—MS)同时测定土壤中的铬(Cr)、镍(Ni)、铜(Cu)、砷(As)、铊(Tl)、铅(Pb)6种重金属元素含量的方法。该方法的相关系数在0.9996~1.000,相对标准偏差在0.669%~3.02%,加标回收率为94.68%~115.5%,检出限为2.004~312.4ng/L,结果表明该方法满足重金属分析的要求。用建立起的方法测定了来自湖南、湖北、云南、贵州、河南、福建、辽宁7个省45个产区烟田土壤中的Cr、Ni、Cu、As、田和Pb6种重金属元素含量;与对应烟叶中的6种重金属含量相比,聚类分析结果表明不同省区间土壤中的重金属含量无明显差异,而烟叶中却差异明显。
简介:针对化探样品批量大,元素多,检出限低等特点,采用水平电极撒料法,对化探样中多种微量元素进行了光谱定量分析。将样品与缓冲剂1:1混匀,采用W-100光栅摄谱仪(光栅刻线1200条,毫米,二级光谱)进行水平撒样摄谱,谱板经暗室处理后,在东德GFE760u测微光度计上用P标尺测光,以AP—logc绘制工作曲线,查出含量。本法采用了特制的撒样漏斗,改善了下料的均匀性,提高了分析精度;以Ge和Pd作内标消除工作条件变化对谱线强度的影响;同时还试选了SiO2:C:Na2SO4=61:30:9的混合物作缓冲剂,提高了弧烧的稳定性,获得了较高的再现性。本文还采用了一种单元素线减光器对Ag3382.9进行减光,使舷的测定上限由5×10-6提高到30×10-6。本法操作简便快速,成本较低,一次可测定Ag、W、Mo、Sn、Bi、Cu、Pb、Zn、Ni、Co、Cr等多种元素,检出限为Ag0.03×10-6,W0.5×10-6,Mo0.05×10-4,Sn0.4×100-6,Ph1×10-6,Zn3×10-6,Cu0.5×10-6,Bi0.1×10-6,Ni0.3×10-6,Co0.3×10-6,Cr1×10-6,基本上达到了化探普查找矿定量分析的要求。
简介:AdsorptionofCr(VI)andp-chloroanilineonthreetypicalsoilcolloidsandpHinfluencewerestudiedusingbatchequilibriummethod.BothofCr(VI)andp-chloroanilineadsorptiononthecolloidscouldbewelldescribedbygeneraladsorptionsimulationequations,TheadsorptionprocesseschangedwithmediapH.WhenCr(VI)andp-chloroanilinecoexistedonsoilcolloids,theirinteractionscouldbeobservedinacertainpHrangetobeaccompaniedwithCr(VI)reduction,whichclearlysuggestedthatasurfacecatalyticreactionoccurredinthissystem.SoilcolloidactedasaneffcientcatalystfortheinteractionofCr(VI)andp-chloroaniline.ThepHvaluesatwhichnointeractionwasobservedwere4.0,4.5and5.0forthecolloidsofindigoticblacksoil,yellow-brownsoilandlatosol,respectively,Capillaryelectrophoresisusedtoanalyzep-chloroanilineprovidedahighseparationefficiencyandshortseparationtime,andneedednomoreextensivepretreatmentofsamples.
简介:ThedistributionandtransformationofaddedandnativeNiinpurplesoilswereinvestigatedwithbothsequentialextractionprocedureandisotopictracertechnique.ThedistributionofaddedandnativeNiwasgreatlydependentonsoilproperties.LowsoilpHwasfavorableforsolubleplusexchangeable(EX)Fraction,whileFe/MnoxidesandclayforFe/Mnoxidebound(OX)andresidual(RES)fractions.TheaddedNi,however,hasnotyetreachedthedistributionequilibriumuptothe150thdayafterincubation.ThiswasreflectedinthefactthattheproportionofEXfractionfromaddedNiwas150%-600%asmuchasthatofnativeNi,whilethatofRESfractionwasonlyabout80%,Onceenteringsoil,theappliedsolubleNiwasrapidlytransformedintootherfractions,buttheorganiccomplexe(OM)fractionofaddedNiwasrelativelystableduringincubation.Thecarbonatebound(CAB)fractionshowedaprogressiveincreaseandattainedapeakvalueafter0-14dofincubationandthereafterdecreasedgradually.TheoccurrencetimeofthispeakadvancedasinitialsoilpHincreased.butthepeakwoulddisappearwheninitialsoilpHwashigherthan7.5(orcontainingfreeCaCO3).ThetransformationprocessesoftheEX,OXandRESfractionscouldbedescribedbyElovichandtwo-constantrateequations,andtheratewerepositivelycorrelatedwithsoilpH,CECandclay.ThesefindingcouldexplainwhytherearedifferencesinecologicalandenvironmentaleffectsofNiindifferentsoilsandatvariousintervals.