Separation of carrier free95mTc from niobium targets irradiated with alpha-particles

A^95mTc tracer with an excellent quality was prepared by a simple sublimation method after α-bombardment of niobium metal. Technetium-95m produced by the⁹³Nb(α,2n)^95mTc reaction was separated from the niobium targets in a quartz tube by heating at 1100°C in an oxygen gas flow. Technetium-95m sublimed as an oxide was deposited on the inner wall of the quartz tube outside an electric furnace, and then collected as a pertechnetate solution by washing with water. The ICP-MS analysis of the^95mTc solution revealed its excellent quality, compared to a^95mTc solution prepared from the same targets through a wet chemical separation method and a commercial^95mTc solution. With this tracer, the precision of ICP-MS analysis of⁹⁹Tc in environmental samples are highly improved.     

Separation of europium, cobalt and zinc on zirconium tungstate ion exchanger

Summary Amorphous zirconium tungstate inorganic ion-exchanger has been prepared under optimum conditions and characterized by IR, X-ray and thermal analysis. Surface area and capacity are determined. It has characteristic IR absorption peaks at 3242, 1628, 955, 868 and 432 cm^-1 and is thermally stable up to 450 °C. Its surface area was 16 m²/g with an exchange capacity of 0.541 meq/g. The sorption of radioactive europium from different media at ambient temperature by the zirconium tungstate (ZW) exchanger has been studied. The aim was to optimize the conditions for sorbing Eu from radioactive waste and cleaned the ZW from for recycling. The effect of contact time, metal concentration, pH and temperature has been measured. Percentual uptake of Eu(III) reaches 95% for HCl at pH 4 and increases with temperature indicating an endothermic sorption process. Uptake of Zn(II) and Co(II) on ZW from acetic acid was found to be 42% and 24% for cobalt and zinc, respectively. Desorption after saturation and the effect of other radioactive ions on the percentual uptake of Eu on ZW were investigated. A solution of 3M HCl releases 90%, 25% and 13% of the loaded Eu(III), Co(II) and Zn(II), respectively.     

Separation of lithium isotopes by N4O2 azacrown ion exchanger

A study on the separation of lithium isotope was carried out with a 1,16-dioxa-4,7,10,13- tetraazacyclooctadecane-4,7,10,13-tetramerrifield peptide resin [N₄O₂·4M]. The resin having N₄O₂ as an anchor group has a capacity of 3.8 meq/g. Upon column chromatography [0.15 cm (I.D)×29 cm (height)] using 0.01 M NH₄Cl as an eluent, the single separation factor, α=1.038 was obtained by the Glueckauf theory from the elution curve and isotope ratios.     

Separation of lithium isotopes by N4S2 azacrown ion exchanger

The novel N₄S₂ azacrown ion exchange resin was prepared. The ion exchange capacity of N₄S₂ ion exchanger was 0.34 meq/g dry resin. A study on the separation of lithium isotopes was carried out with N₄S₂ azacrown ion exchange resin. The lighter isotope,⁶Li is concentrated in the resin phase, while the heavier isotope,⁷Li is enriched in the solution phase. With column chromatography [0.1 cm (I.D.)×32 cm (height)] using 2.0M NH₄Cl as an eluent, separation factor, a=1.034 was obtained.     

Separation of magnesium isotopes by N4S2 azacrown ion exchanger

The chromatographic separation of magnesium isotopes was investigated by chemical ion exchange with 1,16-dithia-4,7,10,13-tetraazacyclooctadecane-4,7,10,13-tetramerrifield peptide resin[N₄S₂·4M] synthesized recently. The capacity of novel N₄S₂ azacrown ion exchanger was 0.34 meq/g dry resin. The heavier isotopes of magnesium concentrated in the resin phase, while the lighter isotopes are enriched in the solution phase. The glass ion exchange column used was 30 cm long with inner diameter of 0.2 cm, and the 1.0M NH₄Cl solution was used as an eluent. The separation factors of²⁴Mg−²⁵Mg,²⁵Mg−²⁶Mg, and²⁴Mg−²⁶Mg were 1.047, 1007, and 1.008, respectively.     

Ion beam induced emissions from solid europium compounds

Impact of energetic heavy particles on europium compound surfaces gives rise to radiative optical emission from reflected and sputtered particles and from the excited states of the solid compounds. In the present paper we discuss the optical spectrum and the sputtered secondary ion mass spectrum observed when solid europium oxide (Eu₂O₃) and europium chloride (EuCl₃) are bombarded with 90 keV Ar⁺ ions from an ion accelerator. We observe the reduction reaction in solid europium chloride (EuCl₃) by bombardment with a 20 A/cm² beam of 90 keV Ar⁺ ions.     

Trace element analysis via heavy ion induced X-ray fluorescence

Ohne ZusammenfassungWork supported by the National Science Foundation, Grant MPS 75-17746.     

Separation of americium from europium by biopolymer microcapsules enclosing Cyanex 301 extractant

Microcapsules enclosing an extractant with strong affinity for Am were prepared by employing a biopolymer gel as an immobilization matrix. A relatively large separation factor between Am and Eu was exhibited by the microcapsule containing of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301, HA) and alginic acid (HALG). The chromatographic separation of these metal ions was accomplished by gradient elution through the column packed with HA-HALG.     

Fast heavy ion induced photon emission from organic solids and plasma desorption mass spectrometry

Fission fragments from a ²⁵²Cf source have been used to study fast heavy ion induced desorption of ions and luminescence in the wavelength region 200–680 nm from samples of Csl, the amino acids valine, isoleucine and tyrosine, and of the peptide substance P. All samples emit photons under fast heavy ion bombardment. Most of the emission is confined to the near-UV region and within narrow time profiles. Analysis of the fast decay regions of the time profiles show that all the compounds have at least a fast and a slow decay component, both in the nanosecond region. The use of such narrow photon signals as start time markers for time-of-flight measurements (TOF) has been demonstrated. As the photon signal is derived directly from the desorption event it gives the true number of starts for a secondary ion TOF spectrum. Characteristics of the photon emission from a CsI target together with correlation studies between the desorbed secondary ions and the photon signal indicate that the light emission is from the bulk of the material and not correlated with the secondary ions.     

Selectivity of ion exchangers in extracting cesium and rubidium from alkaline solutions

We compare the ion exchange selectivity of phenol-type sorbents based on phenol formaldehyde resins, products of condensation of diatomic phenols with formaldehyde, and crosslinked polymer based on C-phenyl[4]resorcinarene resin, for cesium and rubidium ions. It is shown that phenol formaldehyde sorbents are the ones most selective. The interaction of alkali metal cations with the anion of calix[4]arene is investigated via quantum-chemical modeling. It is shown that the selectivity toward cesium and rubidium ions in ion exchangers of the phenolic type is not due to specific interactions of ions with phenolic groups.     

Separation of europium and thulium from mixed KI−H2SO4 solutions

The extraction of Tm with HDEHP from H₂SO₄, HCl and HBr is inversely proportional to the third power of the hydrogen ion concentration while the extraction is small with HDEHP, LA-2 and TBP from binary mixtures of acids. The extraction of both Eu and Tm with HDEHP from KI solutions decreases in the presence of small concentrations of H₂SO₄. The decrease is sharper in case of Eu leading to high separation factors between Eu and Tm from KI?H₂SO₄ mixtures.     

Separation of vanadium isotopes by ion-exchange chromatography

Cation-exchange displacement chromatography of VO2+ was carried out for studying vanadium isotope effects in carboxylate ligand-exchange systems. The heavier isotope 51V was enriched in the carboxylate complex solution. The isotope separation coefficients epsilon(= alpha-1) for 50V/51V were 2.2 x 10(-4) and 2.4 x 10(-4) for citrate and lactate systems at 298 K, respectively. These values are much larger than those obtained in a previous study on the malate system. The existence of binuclear complexes of VO2+ may create the conditions for larger isotope fractionation. From the viewpoint of the process development of isotope separation, the heights equivalent to a theoretical plate of these processes were analyzed and found to be very small in each system due to the homogeneous, small and highly porous resin used. Citrate may be better than the other tested systems for the vanadium isotope separation.     

The nature of europium ion in carbonate solution and polarographic determination of micro amounts of europium

The nature of the complex europium carbonate ion in concentrated carbonate solution was studied polarographically. A polarographic method for the determination of micro amounts of europium ion in the presence of diverse ions (and especially lanthanides) was developed.     

Separation of cesium from intermediate level liquid radioactive waste by solvent extraction with antioxidants

The intermediate level liquid radioactive wastes (RAW) isussed from nuclear power plants have high salt contents ca 200 g·dm^–3, the pH of liquid RAW being 12.5–13.7. A convenient method for separation of cesium under these conditions is solvent extraction with substituted phenols. For this purpose weere tested antioxidants produced in Czechoslovakia: AO 2246 [2,2-methylene-bis-(4-methyl-6-tertbutyl)phenol]; AO 4 [2-tertbutyl-4-(2-phenylpropyl)phenol]; AO 4K [2,6-ditertbuty-4-methylphenol]; AO 301 [2,2-methylene-bis-(4-{2-phenylpropyl}-6-tert-butyl)phenol]; and one antioxidant imporoted from Japan—NOCRAC 2246. This antioxidant is equivalent to AO 2246. After the first experiment it was found that the extraction efficiency for antioxidants AO 4 and Ao 301 is very low and the following experiments were made with AO 2246 (NOCRAC 2246) and AO 4K. Some effects on extracton as, pH of water phase, influence of diluent, influence of concentration of antioxidants, extraction time, were studied. The best results gave antioxidant NOCRAC 2246 in nitrobenzene, the extraction efficiency was 92.3% with pH 13.23.     

Separation of peptides from detergents using ion mobility spectrometry

Mass spectrometry (MS) has dramatically evolved in the last two decades and has been the driving force of the spectacular expansion of proteomics during this period. However, the very poor compatibility of MS with detergents is still a technical obstacle in some studies, in particular on membrane proteins. Indeed, the high hydrophobicity of membrane proteins necessitates the use of detergents for their extraction and solubilization. Here, we address the analytical potential of high-field asymmetric waveform ion mobility spectrometry (FAIMS) for separating peptides from detergents. The study was focused on peptides from the human integral membrane protein CD9. A tryptic peptide was mixed with the non-ionic detergents Triton X-100 or beta-D-dodecyl maltoside (DDM) as well as with the ionic detergents sodium dodecyl sulfate (SDS) or sodium deoxycholate (SDC). Although electrospray ionization (ESI) alone led to a total suppression of the peptide ion signal on mass spectra with only detection of the detergents, use of FAIMS allowed separation and clear identification of the peptide with any of the detergents studied. The detection and identification of the target compound in the presence of an excess of detergents are then feasible. FAIMS should prove especially useful in the structural and proteomic analysis of membrane proteins.     

Common compression factor and bulk modulus quiescence points of liquid cesium

In this paper, a recently developed analytical equation of state (EOS) is used to investigate the bulk modulus of compressed liquid cesium and to locate common compression factor and the bulk modulus quiescence point(s). This EOS is applied quick well to Na and Rb far from T_c. Bulk modulus of liquid cesium have two quiescence points, a sharp one in the range 1100–1500 K and a diffused one in the range 1600–1900 K. Therefore, two types of liquid cesium metal may be identified with characteristic structure and interaction potential energy. It is a constant independent of temperature, however, some residual change is seen due to the change in the values of integral of pair correlation function as temperature is increased. Furthermore, it is related to the shape of the unit cell and the atomic size at equilibrium. Observation of distinct liquid in the metal–nonmetal transition range is compared with NMR studies and molecular dynamic results.     

Sorption characteristics of an economical sorbent material used for removal radioisotopes of cesium and europium

Application study for the evaluation of sorption characteristics of sawdust as an economical sorbent material used for decontamination of radioisotopes cesium and europium from aqueous solution has been carried out in the present work. In this respect, sawdust (untreated and treated by HNO₃) has been prepared from the commercial processing of wood for furniture production. Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N₂ adsorption and DFT software. Radiotracer method onto sawdust from aqueous solutions was studied in a batch technique with respect to pH, contact time, temperature. The kinetics of adsorption of Eu³⁺ and Cs⁺ have been discussed using five kinetic models namely, pseudo-first-order model, pseudo-second-order model, Elovich equation, intraparticle diffusion model, and modified Freundlich equation that have been tested in order to analysis the experimental data. Kinetic parameters and correlation coefficients were determined. It was shown that the second-order kinetic equation could describe the sorption kinetics for two metal ions. The metal uptake process was found to be controlled by intraparticle diffusion. Thermodynamic parameters, such as ΔH, ΔG and ΔS, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures. The obtained results indicated that endothermic nature of sorption process for both ^152+154Eu and ¹³⁴Cs onto sawdust.