简介:Theadsorptionbehaviorsandmechanismofanovelchelateresin,macroporousphosphonicacidresin(PAR)forGd(Ⅲ)wereinvestigated.Thestaticallyanddynamicallysaturatedadsorptioncapacityisrespectively308mg·g-1resinand296mg·g-1resinat298KinHac-NaAcmediumatpH5.6.Gd(Ⅲ)adsorbedonPARcanbereductivelyelutedby0.5~5.0mol·L-1HClusedaseluantandtheelutionpercentageisupto94.7%in1.0mol·L-1HCl.Theresincanberegeneratedandreusedwithoutapparentdecreaseinadsorptioncapacity.Theapparentadsorptionrateconstantisk298=3.96×10-5s-1.TheadsorptionbehaviorofPARforGd(Ⅲ)conformstotheFreundlichisotherm.Thethermodynamicadsorptionparameter,enthalpychange△HofPARforGd(Ⅲ)is22.6kJ·mol-1.Theapparentadsorptionactivationenergy(Ea)ofPARforGd(Ⅲ)is5.0kJ·mol-1.ThemolarcoordinationratioofthefunctionalgroupofPARtoGd(Ⅲ)isabout3∶1.TheadsorptionmechanismofPARforGd(Ⅲ)wasexaminedbyusingchemicalmethodandIRspectrometry.
简介:Reversed-phasepaperchromatographytechniqueisusedforstudyontheextractionmechanismandsep-arationofrareearthelements.Asthestationaryphase,chromatographicpaperstripsareimpregnatedwithasolutionofmonomyristylphosphoricacid(MPA)inchloroform.Mineralacidsareusedasdevelopers.Theeffectofconcentrationofacidsand/orsaltsuponRfhasbeeninvestigated.Accordingtothere-sultsofRfvaluesforagivenrareearthelementinvariousacids,theorderofextractionabilityisHCl>HNO3>H2SO4.Atetradeffectisclearlyobserved.fortheRfvalueofrareearthelements.TheeffectsofotherparametersontheRfvalue,suchasthequantitiesofextractantretainedbythepaperandthetemperaturearealsoexamined.BasedonthedeterminationofthemolarratioofMPAtorareearthelementsandthenumberofH+ionsreleasedinextractionreaction,areasonablemechanismisproposed.Themutualseparationofheavyrareearthelementswillbebetterthanthatofthelightrareearthgroupbecauseofthelargerseparationcoefficientoftheformer.AmixtureofHo-Er-Tm-Luissuccessfullyseparatedbythepresentmethod.
简介:TheextractionofCe(Ⅳ)inH2SO4/H3PO4systemwasinvestigatedsystematicallyusingbifunctionalionicliquidextractants(Bif-ILES)[A336][P507],[A336][P204]and[A336][C272]inn-heptane.TheeffectsofH2SO4concentration,extractantconcentrationandsalting-outagentconcentrationwereobservedindetail.TheextractionmechanismofCe(Ⅳ)inH2SO4/H3PO4systemwasobtained.ThecomparisonwithotherextractantssuchasCyanex923,TBPwasalsostudied.Thermodynamicfunctionsoftheextractionreactionwerecalculated,showingthattheextractionwasanexothermicprocess.TheseparationofCe(Ⅳ)fromRE(Ⅲ)andTh(Ⅳ)wasalsoinvestigated.TheresultindicatedthatCe(Ⅳ)couldbeselectivelyextractedinthissystem.CePO4nanoparticleswereobtainedintheprocessofstrippingusingH2O2inH2SO4/H3PO4system.X-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andspectroscopywereadoptedforthecharacterizationofthesample.
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