一元烷基磷(膦)酸对镅、钕、铕的萃取

    • 摘要: 测定了8种一元烷基磷(膦)酸(HL)在不同pH和不同萃取剂浓度下对示踪量三价镅、钕、铕的萃取分配比D。萃取剂包括2种二烷基磷酸(RO)2POOH、5种烷基膦酸单烷基酯(RO)RPOOH和1种二烷基次膦酸R2POOH,其中R是正辛基、仲辛基或异辛基。由lgD-pH和lgD-lgcH2L2直线的斜率分析可知,这3种元素的萃取反应是相同的。计算了各萃取反应的表观平衡常数Kex。铕的被萃取能力最强,镅和钕的被萃取能力接近,在大多数情况下,镅稍低于钕。随着萃取剂分子中RO基团被R基团取代及正辛基被仲辛基或异辛基取代,萃取能力明显下降,分离因数βEu/Am和βNd/Am略呈上升趋势。

       

      Abstract: THEEXTRACTIONOFAm,NdANDEuBYMONOFUNCTIONALALKYLPHOSPHORIC,PHOSPHONICANDPHOSPHINICACIDSZhuYongjun(InstituteofNuclearEnergyTechnology,TsinghuaUniversity,P.O.Box1021,Beijing102201)ABSTRACTTheextractionofamericium,neodyniumandeuropiumbyeightmonofunctionalalkylphosphoric,phosphonicandphosphonicacids(HL)aremeasuredunderdiferentpHandex-tractantconcentrations.Theseextractantsaretwodialkylphosphoricacids(RO)2POOH,fivealkylphosphonicacidmonoalkylesters(RO)RPOOH,andonedialkylphosphinicacidR2POOHinwhichRisn-octyl,s-octylori-octylgroup.TheslopeanalysisoflgD-pHandlgD-lgcH2L2straightlinesshowsthesameextractionmechanismofthesethreeelements.TheapparentequilibriumconstantsofextractionreactionsKexarecalculated.Theextractablilityofeuropiumisthestrongest,whilethatofamerciumandneodyniumareclosetoeachotherandtheformerisslightlylowerthanthelatterinmostcases.Theextractionpoweroftheex-tractantsdecreasesapparentlywiththereplacementofROgroupbyRgroupandthereplace-mentofn-octylgroupbys-octyloriso-octylgroupalongwiththeslightincreaseofsepara-tionfactors.KeywordsAmNdEuAlkylphosphoric,phosphonicandphosphinicacidExtraction

       

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