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:有色金属的分类很多,大约有80多种,大致按其比重、价格、在地壳中的储量及分布情况和被人们发现与使用情况的早晚等分为五大类。(1)重有色金属;指比重大于4.5的有色金属。包括铜,镍,锢,铅,锌,锑,汞,镉和铋。(2)轻有色金属;指比重小于4.5的有色金属。包括铝,镁,钙、钾、锶和钡。(3)贵金属;指在地壳中含量少,开采和提取都比较困难,对氧和其它试剂稳定,价格比一般金属贵的有色金属。包括金、银。和铂族元素。一般比重都较大,熔点较高在916—3000度,有很好的化学稳定性、优良的抗氧化性及耐腐蚀性。(4)半金属;一般指硅、硒、碲、砷和硼五种元素。其物理化学性质介于金属和非金属之间。如砷是非金属,但它能传热和导电。
简介:Thesimplemodelfor4f-5dtransitionsoflanthanideionsincrystalswasextendedtodealwiththecaseoftheoctahedralcrystalfield,whereforthet2componentof5dorbitalsthespin-orbitinteractioncouldnotbeneglectedduetoincompletequenchingofthe5dorbitalangularmomentum.Theenergylevelsforthe4fN-15dconfigurationandtherelativelinestrengthsforthe4fN4fN-15dtransitionwerecalculatedindetail.Theresultwasappliedtotheinterpretationofthelow-temperature4f-5dexcitationspectrumofCs2NaYCl6∶Tb3+.
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.