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1.
H. Seiler 《Helvetica chimica acta》1971,54(2):533-537
1. Thin-layer chromatography is applied to the separation of the nuclids of the decay-chain: 125Sn → 125mTe. Different factors influencing the separation are investigated. The method can be used for the carrier-free separation of 125mTe. 2. As, Sb and Sn have been separated by thin-layer chromatography. 相似文献
2.
The development of a new radionuclide generator, based on118Te/118Sb, has been studied. The 3.5 minute118Sb daughter activity decays principally by positron emission and has potential use as a flow tracer. The118Te parent is conveniently produced by proton bombardment of antimony targets. A simple and efficient scheme for the separation of radiotellurium from proton-irradiated antimony targets has been developed, and thin-target cross sections for121Sb(p, 4n)118Te and competing reactions have been determined. For antimony targets irradiated with 46 MeV protons, the yields (mCi/g Ah) of118Te,119mTe and119Te were measured to be 0.71, 0.33 and 1.9, respectively. The adsorption and elution characteristics of activated carbon for tellurium have been evaluated for use as a column chromatography adsorbent in a118Te/118Sb generator. The conditions for optimal118Sb elution and minimal118Te breakthrough for promising systems are presented. 相似文献
3.
S. Ambe 《Journal of Radioanalytical and Nuclear Chemistry》1984,81(1):77-87
Adsorption behaviour of trace elements, In(III), Sn(IV), Sb(V) and Te(IV) on activated carbon and graphite powder was studied. Adsorption characteristics of the ions enabled the separation of In(III)–Sn(IV), Sn(IV)–Sb(V) and Sb(V)–Te(IV) pairs. Applications to practical separation, milking of113mIn from113Sn, removal of tin impurity from119Sb, and milking of119Sb from119mTe, are presented. 相似文献
4.
The solutions of carrier-free125mTe(VI) have been prepared by oxidizing125mTe(IV) with bromine. Using carrier-free125mTe(VI) as a tracer, the effects of pH, NaCl concentration, and tellurium(VI) concentration on the adsorption and colloidal properties of tellurium(VI) in NaCl solution have been studied. It has been found that traces of tellurium(VI) are adsorbed on filter paper and show colloidal behavior in the basic region. A method has been devised for the separation of carrier-free125mTe from its parent nuclide125Sb, based on the adsorption properties of125mTe(VI) in basic solutions. 相似文献
5.
Adsorption and desorption of95Zr−95Nb,99Mo,103Ru,132Te and239Np in a HCl-alumina system were studied in order to purify99Mo and132Te obtained by the cation-exchange separation of fission products and to prepare highly pure99mTc and132I generators.99Mo and132Te, of which radionuclidic purity was over 99.99% and 99.999%, respectively, could be obtained by passing the cation-exchange
separated Mo and Te fractions through alumina columns, by washing with HCl and finally by eluting99Mo with 1M NH4OH and132Te with 3M NaOH. In order to raise the recovery of99Mo and132Te from the alumina columns, they should be eluted as quickly as possible after the adsorption. The direct use of the alumina
column containing99Mo or132Te as the generator allowed milking of99mTc or132I, of which radionuclidic purity was over 99.999%. Milking yields of99mTc with 0.1M HCl and132I with 0.01M NH4OH were 77% and 90%, respectively. The latter value was much higher than that in usual performance of the generator. 相似文献
6.
Air‐sensitive black crystals of the new compound [Mn(en)3]Te4 were synthesized by reacting MnCl2 · 4 H2O, K2Te3 and elemental Te in 1,2‐ethanediamine (en) under solvothermal conditions at 433 K. The compound crystallizes in the monoclinic space group P21/n with lattice parameters a = 839.51(7) pm, b = 1551.3(1) pm, c = 1432.6(1) pm, and β = 90.28(2)°. Isolated [Mn(en)3]2+ cations and Te42– anions are arranged in an alternating fashion parallel to the crystallographic b‐axis. One terminal Te atom of the Te42– anions exhibits a short intermolecular contact to a neighboured anion thus forming Te84– anions. A slightly longer interionic Te…Te separation is observed between two of the inner Te atoms of neighboured Te84– anions. Taking these longer separations into account infinite Te‐chains are formed running parallel to [001]. The intermolecular Te…Te interactions affect the Te–Te bond lengths within the Te42– anion leading to a lengthening of the average Te–Te distance. Short N–H…Te distances indicate hydrogen bonding between the cations and anions. DTA‐TG measurements show that at 441 K the material decomposes in one step. The resulting crystalline material consists of MnTe2 and Te. 相似文献
7.
F. H. El-Sweify 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):55-59
Chelex-100, in the anionic form has been studied for its ability to perform selective separation and concentration of some metal ions of nuclear importance from mineral acid solutions. The sorption behavior of Zr(IV)–Nb(V), Mo(VI), Tc(VII), Te(IV) and U(VI) from solutions of hydrochloric and sulphuric acids on Chelex-100 has been studied under static and dynamic conditions. Mo(VI) and Tc(VII) have been concentrated on the resin from hydrochloric or sulphuric acid solutions at low acidities probably, as the anions MoO
4
2–
and TcO
4
–
, respectively. Te(IV) has been isolated from hydrochloric acid solutions of normalities 6 in the form of the anionic chloro complex TeCl
6
2–
. Optimum conditions for elution and separation of Mo(VI), Tc(VII), Te(IV) and U(VI) were recommended. 相似文献
8.
Dr. Zong‐Hong Lin Zih‐Yu Shih Prathik Roy Prof. Huan‐Tsung Chang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(39):12330-12336
A facile approach has been developed for the preparation of various morphologies of Au–Ag2Te nanomaterials (NMs) that exhibit strong photocatalytic activity. Te NMs (nanowires, nanopencils, and nanorice) were prepared from TeO2 in the presence of various concentrations (16, 8, and 4 M ) of a reducing agent (N2H4) at different temperatures (25 and 60 °C). These three Te NMs were then used to prepare Au–Ag2Te NMs by spontaneous redox reactions with Au3+ and Ag+ ions sequentially. The Au–Ag2Te nanopencils exhibit the highest activity toward degradation of methylene blue and formation of active hydroxyl radicals on solar irradiation, mainly because they absorb light in the visible region most strongly. All three differently shaped Au–Ag2Te NMs (10 μg mL?1) provide a death rate of Escherichia coli greater than 80 % within 60 min, which is higher than that of 51 % for commercial TiO2 nanoparticles (100 μg mL?1). Under light irradiation, the Au NPs in Au–Ag2Te NMs enhance the overall photo‐oxidation ability of Ag2Te NMs through faster charge separation because of good contact between Ag2Te and Au segments. With high antibacterial activity and low toxicity toward normal cells, the Au–Ag2Te NMs hold great potential for use as efficient antibacterial agents. 相似文献
9.
The separation of radioiodine was investigated using two wet chemical procedures, namely anion-exchange and solvent extraction.
Some factors affecting the separation, such as HCl, NaOH and tetrabutyl ammonium bromide (TBAB) concentrations, used solvents
ethyl acetate, benzene and carbon tetrachloride and different quaternary ammonium salts were studied. For each procedure the
optimum conditions were deduced. The separation of 123I was effected from proton-irradiated 123Te target under the optimized conditions of the two procedures. The yield of 123I obtained using the Dowex 21k anion-exchanger and tetrabutyl ammonium bromide solution as eluting agent was 88±3%; the radionuclidic
purity was high and the time needed was 60 minutes. In solvent extraction process using TBAB in ethyl acetate as the extracting
agent, the yield of 123I was low (47±3%), the radionuclidic purity was not as good as in the anion-exchange method, and the time needed was 150 minutes.
Therefore, the anionexchange method is preferable. A comparison of this wet chemical method of separation of 123I with the commonly used dry distillation method is given. The wet method appears to be more suitable when a 123Te metal target is used. 相似文献
10.
A. V. Tikhomirov 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(1):157-160
Large-scale production of radioisotopes for medical application was impeded by limited capabilities of the electromagnetic separation. Nowadays the centrifuge separation process involves more than two dozens of chemical elements. The cost of isotopes is incomparably lower than of those produced by electromagnetic separation, which has made enriched isotopes more practicable and has extended their application scope. The development of new isotope targets has ensured the realization of more effective schemes of 123I production. The processes of 124Xe and 123Te production are reviewed. 相似文献
11.
K. F. Hassan S. Spellerberg B. Scholten Z. A. Saleh S. M. Qaim 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):689-694
A novel anion-exchange chromatographic method for separation of radioiodine from an antimony target irradiated with 3He- or α-particles was developed, with separation yield of radioiodine amounting to 90 ± 5 % and its decontamination factor from the Te and Sb radionuclides to ~104. The optimized separation method developed was then applied to the production of 124I via the 121Sb(α,n)124I process using a highly enriched 121Sb target. Quality control tests showed that the separated 124I occurred >99 % as iodide and the longer lived impurities 126I and 125I amounted to 0.16 % and <0.05 %, respectively. The trace level of inactive Sb impurity was determined by ICP–OES. 相似文献
12.
V. K. Karandashev S. S. Grazhulene Yu. V. Yakovlev 《Journal of Radioanalytical and Nuclear Chemistry》1986,106(4):223-231
A simple procedure of neutron activation analysis for the determination of 16 impurities in PbxSn1–xTe with detection limits from 1×10–4% for Ni and Zr to 2×10–9% for Sc has been developed. The procedure is based on extraction chromatographic separation of impurities from the irradiated sample. 相似文献
13.
Summary A method combining co-precipitation of traces of elemental Te on Se as carrier with organic solvent flotation is described. The best reduction and flotation conditions (hydrochloric and phosphinic acid concentrations, amount of Se, solvent used) were chosen. The recoveries for 100g of Te(IV) (AAS measurement in MIBK) and 2g of Te (radiochemical measurement with127Te) were 98% and 84–88%. The method was applied for separation of Te(IV) from copper metallurgy dust and slag.
Flotationsverfahren zur Abtrennung von elementarem Tellur mit Selen als Kollektor
Zusammenfassung Die Kombination der Mitfällung von Spuren elementaren Tellurs auf Selen als Trägersubstanz mit der Flotation mit Hilfe eines organischen Lösungsmittels wurde beschrieben. Die besten Bedingungen zur Reduktion und Flotation (Salzsäure-und Phosphinsäurekonzentration, Selenmenge, Lösungsmittel) wurden ausgewählt. Die Wiederfindungsraten für 100g Te(IV) (AAS-Bestimmung in MIBK) und 2g Te (radiochemische Messung mit127Te) waren 98% bzw. 84–88%. Das Verfahren wurde zur Trennung von Te(IV) aus dem Staub und der Schlacke der Kupfermetallurgie verwendet.相似文献
14.
B. Mukhopadhyay S. Lahiri K. Mukhopadhyay A. Ramaswami 《Journal of Radioanalytical and Nuclear Chemistry》2003,256(2):307-310
Heavy-ion activation with ~55 MeV 11B beam on silver target leads to the production of carrier-free 111In, 116,117Te and 116,116m,117Sb radioisotopes in the target matrix. Liquid-liquid extraction, using Aliquat-336 and trioctylamine (TOA) as liquid anion exchangers in HNO3 and HCl medium, respectively, and di-(2-ethylhexyl)phosphoric acid (HDEHP) as liquid cation exchanger in ammoniacal medium was used to investigate the separation of the produced radioisotopes from the bulk target matrix. 相似文献
15.
Titanium dioxide nanoparticles (nano-TiO2) were employed for the sorption of Te(IV) ions from aqueous solution. A detailed study of the process was performed by varying the sorption time, pH, and temperature. The sorption was found to be fast, equilibrium was reached within 8 min. When the concentration of Te(IV) was below 40 mg L−1, at least 97% of tellurium was adsorbed by nano-TiO2 in the pH range of 1-2 and 8-9. The sorbed Te(IV) ions were desorbed with 2.0 mL of 0.5 mol L−1 NaOH. The sorption data could be well interpreted by the Langmuir model with the maximum adsorption capacity of 32.75 mg g−1 (20 ± 0.1 °C) of Te(IV) on nano-TiO2. The kinetics and thermodynamics of the sorption of Te(IV) onto nano-TiO2 were also studied. The kinetic experimental data properly correlated with the second-order kinetic model (k2 = 0.0368 g mg−1 min−1, 293 K). The overall rate process appeared to be influenced by both boundary layer diffusion and intra-particle diffusion. The mean energy of adsorption was calculated to be 17.41 kJ mol−1 from the Dubinin-Radushkevich (D-R) adsorption isotherm at room temperature. Moreover, the thermodynamic parameters for the sorption were estimated, and the ΔH0 and ΔG0 values indicated the exothermic and spontaneous nature of the sorption process, respectively. Finally, Nano-TiO2 as sorbent was successfully applied to the separation of Te(IV) from the environmental samples with satisfactory results (recoveries >95%, relative standard deviations was 2.0%). 相似文献
16.
Dr. Robin Weiss Dr. Emmanuel Aubert Loic Groslambert Prof. Dr. Patrick Pale Dr. Victor Mamane 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(25):e202200395
The chalcogen bonding (ChB) ability of Te is studied in symmetrical diaryl ditellurides ArTeTeAr. Among the two Te σ-holes, the one along the less polarized Te−Te bond was calculated as the more electropositive. This counter-intuitive situation is due to the hyperconjugation contribution from Te lone pair to the σ* of the adjacent Te which coincides with σ-hole along the more polarized Te−Ar bond. ArTeTeAr showed notable structural features in the solid state as a result of intermolecular Te⋅⋅⋅Te ChB, such as a Te4 rectangle through dimer aggregation or a triangular Te3 motif, where one Te interacts with both Te atoms of a neighboring molecule through both its σ-hole and lone pair, in a slightly frustrated geometry. Lewis acidity of ArTeTeAr was also evaluated by NMR with R3PO as σ-hole acceptors in different solvents. Thus, 125Te NMR allowed monitoring Te⋅⋅⋅O interaction and delivering association constants (Ka) for 1 : 1 adducts. The highest value of Ka=90 M−1 was measured for the adduct between ArTeTeAr bearing CF3 groups and Et3PO in cyclohexane. Notably, by using nBu3PO, Te⋅⋅⋅O interaction was revealed by 19F-1H HOESY showing spatial proximity between CF3 and CH3 of nBu3PO. 相似文献
17.
For the determination of trace elements in neutron irradiated, selenium by gamma-ray spectrometry the separation of the matrix activity is often necessary. In model experiments the decontamination of cation and anion impurities from the matrix solution was investigated by the counter current ion migration. After a processing of 3 hrs the trace activities of Co, Cr, Ga, Na and Zn were decontaminated from Se with a factor of >103. For the trace elements As and Te representing the anionic constituents, a decontamination factor of 3·102 was obtained. 相似文献
18.
A Study of Competitive Coordination of Benzochalcogenazole Ligands by Heteronuclear NMR Spectroscopy
Borodkina I. G. Uraev A. I. Borodkin G. S. Sadekov I. D. Garnovskii A. D. Minkin V. I. 《Russian Journal of General Chemistry》2003,73(11):1810-1814
Complexes of 2-methyl(phenyl)benzo-1,3-tellurazole and 2-methyl(phenyl)benzo-1,3-selenazole with tungsten pentacarbonyl and boron trifluoride were studied by heteronuclear NMR spectroscopy (1H, 13C, 77Se, and 125Te). The coordination mode of the ambident ligand can be determined from the coordination shifts of the 125Te and 77Se NMR signals: upfield at coordination via Te and Se atoms and downfield at N coordination. 相似文献
19.
The reduction of Te(IV) at tungsten electrodes in basic and neutral KCl?AlCl3 melts has been studied in the temperature range from 300 to 400°C using cyclic voltammetry and differential pulse polarography. In basic melts Te(IV), present as TeCl62? and TeCl5?, is reduced to soluble Te(II) species, which can be further reduced to elementary tellurium insoluble in tungsten. The divalent species are stabilized by increasing the temperature. From the pCl? dependence of the reduction process, Te(II) in basic melts is suggested to be present as TeCl3? and TeCl2. In neutral melts a third oxidation state (possibly monovalent tellurium) is formed when Te(II) is reduced. 相似文献
20.
R. Naumann und W. Schmidt 《Fresenius' Journal of Analytical Chemistry》1968,240(3):170-175
Zusammenfassung Die kathodenstrahlpolarographische Bestimmung von Ni, Pb, Cu, Co, Fe, Mo, Te, Sn, Zn, Bi, Cd, Tl in Tetrachlorogoldsäure wird beschrieben. Die Nachweisgrenzen liegen im 10–4%- bzw. 10–5%-Bereich (Ni, Co, Mo). Die Spuren werden über einen Ionenaustauscher AG 1X8 untereinander und von der Matrix getrennt.
Cathode-ray polarographic determination of trace elements in tetrachloroauric acid after separation by ion exchange
A method is described for the cathode-ray polarographic determination of traces of Ni, Pb, Cu, Co, Fe, Mo, Te, Sn, Zn, Bi, Cd, Tl in H(AuCl4). Gold is separated from the trace metals by absorption on the strongly basic anion-exchange resin AG 1X8. The detection limits are within the ranges of 10–4% and 10–5% ((Ni, Co, Mo).相似文献