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1.
A method with a sensitivity of 2·10−7 to 1·10−10% has been developed for determining Yb, Ho, Dy, Gd, Eu, Sm and La impurities in metallic uranium by means of neutron activation. The method is based on a preliminary chromatographic separation of the total amount of rare earth elements from uranium by passing the solution in sulphuric acid through KU-2 cation exchange resin and eluting the traces of uranium retained by the resin with a solution of ascorbic acid. The rare earth impurities are then eluted from the resin with 4–5N HCl, evaporated, and irradiated for 20 hours with a neutron flux of 1.2·1013 n·cm−2·sec−1. Subsequently the traces of the rare earth elements are co-precipitated with Fe(OH)3, dissolved in concentrated HCl and separated from the iron and other impurities by passing the solution through Dowex 1X8 anion exchange resin in the chloride form. The individual rare earth elements are then separated from each other using KU-2 cation exchange resin and a solution of ammonium α-hydroxyisobutyrate as the eluant.  相似文献   

2.
In determining the trace impurities existing in high-purity rare earth samples by the neutron activation analysis, there are much interference due to nuclides induced from neutron induced second order nuclear reaction. This paper presents the degree of interference calculated over the ranges of irradiation time from 105 to 107 sec and of thermal-neutron flux from 1·1012 to 1·1015 n·cm−2·sec−1. According to the results of these calculations, degree of interference under the neutron irradiation condition for 288 hrs in the thermal-neutron flux of 3·1013n·cm−2·sec−1 is concluded to be 6.4·106 ppm Gd in Eu, 2.2·104 ppm Sm in Eu, 1.9·104 ppm Ho in Dy, 1.1·103 ppm Eu in Sm, 1.1·102 ppm Ce in La and 1.1·10 ppm Tb in Gd, respectively. Especially, the Gd determination in the Eu target is extremely affected by153Gd formed from the151Eu (n, γ) reaction. On the contrary, this reaction is effective in producing153Gd activity.  相似文献   

3.
The separation procedure for Ag, B, Cd, Dy, Eu and Sm as impurities in Gd matrix using ICP-AES technique with an extraction chromatographic column has been developed. The spectral interference of the Gd matrix on the elements was eliminated using a chromatography technique with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) as the mobile phase and XAD-16 resin as the stationary phase. Ag+, B4O72−, and Cd2+ were eluted with 0.1 M HNO3, while rare earth ions were not. The best eluent for separating Eu and Sm in the Gd matrix was 0.3 M HNO3. The limit of quantitation for these elements was 0.6-3.0 ng mL−1. The recovery of Ag, B, and Cd was 90-104% using 0.1 M HNO3 as the eluent, while that of Eu, Gd, and Sm ranged from 100 to 102% with 0.3 M HNO3. Dy was recovered quantitatively with 4 M HNO3. The relative standard deviation of the methods for a set of three replicates was between 1.0 and 15.4% for the synthetic and standard Gd solutions. The proposed separation procedure was used to measure Ag, B, Cd, Dy, Eu, and Sm in a standard Gd solution.  相似文献   

4.
 Double rare earth monomethylammonium selenates of the general formula CH3NH3 Ln (SeO4)2·5H2O (Ln = Sm, Eu, Gd, Tb, Ho, Y) were synthesized and characterized using X-ray powder diffraction and infrared spectroscopy. The thermal decomposition of the compounds were investigated using TG, DTG, and DTA techniques.  相似文献   

5.
For the simultaneous determination of many elements in small biological samples, a multi-element analysis has been developed using neutron activation. After a 24-hr irradiation in a neutron flux of 2.5·1014 n·cm−2·sec−1 and after immediate chemical separation without cooling, it was possible to analyse 24 elements in bovine liver (NBS-SRM 1577). The separation apparatus, set up in a shielded cell can work four samples simultaneously, and its operation is fast enough to allow the detection of radioisotopes with a half-life of about 2 hrs (165Dy,57mSr,56Mn). Amounts lower than 10−3 μg of Dy, Eu, Pr, Sm and Yb were determined.  相似文献   

6.
Summary.  Double rare earth monomethylammonium selenates of the general formula CH3NH3 Ln (SeO4)2·5H2O (Ln = Sm, Eu, Gd, Tb, Ho, Y) were synthesized and characterized using X-ray powder diffraction and infrared spectroscopy. The thermal decomposition of the compounds were investigated using TG, DTG, and DTA techniques. Corresponding author. E-mail: vrajgaonkar@yahoo.com, vrajgaonkar@mail.mu.ac.in Received November 5, 2001. Accepted (revised) March 6, 2002  相似文献   

7.
Weinschenkite-type LnPO4·2H2O (Ln is Gd, Tb, Dy, Ho, Y, Er, Tm or Yb) and rhabdophane-type, LnPO4·H2O (Ln is La, Ce, Pr, Nd, Sm, Eu, Gd, Tb or Dy) have been investigated by IR absorption spectroscopy (4000–400 cm−1) and Raman scanning spectroscopy (1400–100 cm−1).The IR spectra of weinschenkite-type LnPO4·2H2O (Ln is Gd→Yb) are characterized by a band at 750±6 cm−1 and the occurrence of a doublet in the region of the HOH bending vibrations, the low-frequency component exceeding the first high-frequency component in intensity. This rather peculiar pattern has already been observed in other compounds of similar chemical composition and is interpreted as arising from the presence of water molecules coordinated to the same metal cation. The Raman and IR spectra of these compounds have been interpreted in a manner based on the known structure of CaSO4·2H2O, which is isostructural with the weinschenkite-type compounds.The Raman and IR spectra of rhabdophane-type LnPO4·H2O is analyzed on the basis of the knowledge of the space group of rare earth orthophosphates rhabdophane-type. Its relation with the spectra of rare earth orthophosphates weinschenkite-type is discussed.  相似文献   

8.
Zusammenfassung Substanzen der ZusammensetzungLnCl3·3H2 Box * (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) und LaBr3·3 H2 Box wurden isoliert und durch Thermoanalyse, IR-Absorptionsspektren und Röntgenstreuung charakterisiert.
Compounds of the rare earth elements with -benzoin oxime
Compounds of compositionLnCl3·3 H2 Box * (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) and LaBr3·3H2 Box were isolated and characterized by thermoanalysis, IR spectroscopy and X-ray diffraction.
  相似文献   

9.
Results obtained from the analysis of sediments surface samples taken from rivers mouth and polluted marine environment were analyzed for REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy, Lu and Yb using instrumental neutron activation analysis. Thirty surface samples were collected from ten sites in the coastal marine sediments of the South China Sea along 957 km stretch of the east coast of Peninsular Malaysia. The samples prepared in the powdered form before irradiating them in a neutron flux of ~4 × 1012 n cm−2 s−1 at 750 kW power using the TRIGA Mark II research reactor at Malaysian Institute for Nuclear Technology (MINT). Results of the total concentration are used to establish baseline data in environmental pollution assessment and to develop the correlations between the Ce/Ce* anomalies and the distribution patterns of some the light rare earth elements (LREEs) and the heavy rare earth elements (HREEs). The Chondrite-normalized REE pattern from each site examined and used to explain the sedimentation patterns by anthropogenic activities and by natural processes such as shoreline erosion, weathering deposits. Shale-normalized (NASC) patterns suggest enrichment of LREEs relative to the HREEs with a positive Ce/Ce* anomaly. Validation of the used method was done using a Soil-7 SRM.  相似文献   

10.
Thirteen solid ternary complexes Ln(Pdc)3(Phen) (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu;) have been synthesized in absolute ethanol by rare-earth element chloride low hydrate reacting with the mixed ligands of ammonium pyrrolidinedithiocarbamate (APdc) and 1,10-phenanthroline · H2O (o-Phen · H2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes showed that the Ln3+ ion was coordinated with six sulfur atoms of three Pdc and two nitrogen atoms of o-Phen · H2O. It was assumed that the coordination number of Ln3+ is eight. The constant-volume combustion energies of the complexes, Δc U, were determined by a precise rotate-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, Δc H m o , and standard molar enthalpies of formation, Δf H m o were calculated. The text was submitted by the authors in English.  相似文献   

11.
Ten new rare earth complexes with Schiff base (HL) derived from phthalaldehyde with two-CHO groups and lysine, which has unsymmetrical α-and ε--NH2 groups, were synthesized and characterized by elemental analysis, TG-DTA analysis, UV-Vis, IR, and 1H NMR spectra. They were confirmed to be as LnL2(NO3)·4H2O (Ln=La, Pr, Nd, Sm, Y) and LnL2(NO3)·3H2O (Ln=Gd, Tb, Dy, Er, Yb), respectively. Furthermore, their coordination mechanism, spectral properties and probable molecular structures were also discussed. __________ Translated from Journal of Zhejiang University (Science Edition), 2005, 32 (5) (in Chinese)  相似文献   

12.
CeO2-based solid solutions with a fluorite structure are promising materials as electrolytes of medium-temperature electrochemical devices: electrolytic cells, oxygen sensors, and solid oxide fuel cells. In this work, studies are presented of the effect of the dopant cation radius and its concentration on the physico-chemical properties of the Ce1 − x Ln x O2 − δ solid solutions (x = 0–0.20; Ln = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) and also of multicomponent solid solutions of Ce1 − x Ln x/2Ln′ x/2O2 − δ (x = 0–0.20; Ln = Sm, La, Gd and Ln′ = Dy, Nd, Y) and Ce1 − xy Sm x M y O2 − δ (M = Ca, Sr, Ba) obtained using the solid-phase synthesis technique. Electric properties of the samples were studied in the temperature range of 623–1173 K and in the oxygen partial pressure range of 0.01–10−22 MPa. The values of oxygen critical pressure ( pO2 * )\left( {p_{O_2 }^* } \right) are presented, at which the ionic and electron conductivity values are equal. The values were calculated on the basis of experimental dependences at 1023 K at the assumption that the ionic conductivity value is determined only by the dopant concentration and its effective ionic radius and is independent of the oxygen partial pressure.  相似文献   

13.
A method for the simultaneous determination of trace Dy, Eu, Gd and Sm in nuclear grade uranium oxide by Inductively Coupled Plasma Atomic Emission Spectrometry has been developed. The process of uranium extraction and ICP/AES optimization are investigated. The detection limits of Dy, Eu, Gd and Sm are 0.003, 0.002, 0.006 and 0.010 μg/ml respectively, and more than 90% recovery can be obtained.  相似文献   

14.
单N-乙酸取代O2N2大环配体及其稀土配合物的合成与表征   总被引:2,自引:0,他引:2  
Aseries of new rare earth complexes LnL(NO3)2·2H2O(Ln=La,Pr,Nd,Sm,Eu,Gd,Dy,Yb;L=1,2-diaza-3,4: 9,10-dibenzo-5,8-dioxyacyclopentadecane-N-acetic ion) were prepared. The complexes were characterized by elemental analysis, ICPmethod, IRspectra, 1H NMRand Molar conductance. It was found that the ether oxygen, carboxy oxygen and nitrogen atoms of the ligand are coordinated to the metal ion, as well as a free nitrate and coordianted nitrate ion in the complex.  相似文献   

15.
By diffusion in gel medium new complexes of formulae: Nd(btc)⋅6H2O, Gd(btc)⋅4.5H2O and Er(btc)·5H2O (where btc=(C6H3(COO)3 3−) were obtained. Isomorphous compounds were crystallized in the form of globules. During heating in air atmosphere they lose stepwise water molecules and then anhydrous complexes decompose to oxides. Hydrothermally synthesized polycrystalline lanthanide trimellitates form two groups of isomorphous compounds. The light lanthanides form very stable compounds of the formula Ln(btc)⋅nH2O (where Ln=Ce−Gd and n=0 for Ce; n=1 for Gd; n=1.5 for La, Pr, Nd; n=2 for Eu, Sm). They dehydrate above 250°C and then immediately decomposition process occurs. Heavy lanthanides form complexes of formula Ln(btc)⋅nH2O (Ln=Dy−Lu). For mostly complexes, dehydration occurs in one step forming stable in wide range temperature compounds. As the final products of thermal decomposition lanthanide oxides are formed.  相似文献   

16.
By reaction of hydrated rare earths chlorides (M = La, Nd, Sm, Gd, Dy, Er, Yb, Y) with orthoformates, the following adducts have been prepared: MCl3· 4MeOH, MCl3 ·3EtOH (M = La, Nd, Sm, Gd, Yb), MCl4 · 4 EtOH (M = Dy, Er, Y); adducts MCl3 · 3iso-PrOH have been prepared by successive action of methyl orthoformate and of 2-propanol. The solubilities of these adducts in the corresponding alcohols at 25° (for the lanthanum adducts equally at 0 and 50°) are given. Two examples of the transsolvatation of these compounds, yielding adducts with weakligands, are described.  相似文献   

17.
A new Schiff base ligand, 3-tryptimino-1-phenyl-butan-1-one (TPB), was synthesized. The fluorescence intensity of its terbium(III) complex was greatly enhanced by addition of 1,10-phenanthroline to an acetonitrile solution. Spectrofluorimetric determination of trace amounts of Tb3+ was performed based on this effect. The excitation and emission wavelengths are 293 and 546 nm, respectively. Under optimal conditions, the fluorescence intensities varied linearly with the concentration of Tb3+ in the range of 2.0 × 10−6 to 7.0 × 10−6 M with a detection limit of 2.4 × 10−9 M. Interference by some rare earth ions is described. This method was applied to the determination of trace amounts of terbium(III) in a high purity Y2O3 matrix. The mechanism of fluorescence enhancement was also studied.  相似文献   

18.
Mixed systems of a series of rare earth metals such as La, Ce, Pr, Nd, Sm, Eu, and Yb and their low-valent rare earth diiodides exhibit excellent reducing ability toward the reductive deiodation from 1-iodododecane as a model compound compared with their single systems. More importantly, under photoirradiation conditions, the C-I bond reduction using ‘Ln/LnI2’ takes place efficiently in refluxing THF, even in the cases of heavy rare earths such as Gd, Tb, Dy, Ho, Er, and Tm.  相似文献   

19.
Nine new heteropolytungstates, (NH4)16[LnSb9W21O86]-xH2O, (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Dy or Yb) have been prepared from [NaSb9W21O86]18−, and characterized by elemental analysis, i.r., u.v., emission spectra, magnetic susceptibility, and electrochemistry. Based on183W-n.m.r. spectroscopy of the lanthanum complex, the lanthanide cations occupy the central site in the structure previously demonstrated for the sodium derivative.  相似文献   

20.
Pyridine-2,5-dicarboxylic acid, known as isocinchomeric acid is one of six isomers containing two carboxylic groups. Light lanthanide (III) complexes with pyridine-2,5-dicarboxylic acid with general formula Ln2L3·nH2O, where n = 8, 9, were obtained. Their thermal and spectroscopic properties were studied. Sodium salt was obtained as Na2L·H2O. Hydrated complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) are stable to 313–333 K, whereas Na2L·H2O is stable to about 333 K. Dehydration process for all compounds runs in one stage, next they decompose into appropriate lanthanide oxalates, oxocarbonates carbonates and finally to metal oxides. Bands of νCOOH vibrations at 1736 and 1728 cm−1 disappear on complex spectra and νas and νs of COO groups appear thus indicating that complexation process took place.  相似文献   

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