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1.
The separation of metallic impurities from uranium by anion exchange with a Dowex 1×8 resin has been investigated. The following elements can be quantitatively separated from 400 mg uranium using a 1 cm diameter 15 or 30 cm long column. The elements Ag, Al, Ba, Ca, Cr, Cs, K, Mg, Mn, Na, Ni, Rb, REE, Sc, Th, Ti and Y can be separated by eluting the elements with conc. HCl. Uranium is retained by the resin. Al, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, REE and V can be separated by eluting with 0.01 N H2SO4. Uranium is retained by the resin. Cd and Zn can be separated by first eluting uranium with 0.5 N HCl and then eluting Cd and Zn with 1 N NH3. Hf, Zr and V can be separated by eluting with 5 N HCl but some uranium contamination is unavoidable.  相似文献   

2.
In a study on gold containing antirheumatic agents, the portion of gold that was eliminated via liver was quantified. Seven patients whose gall bladders had just been removed surgically received 5 tablets RIDAURA® containing a total amount of 4.35 mg gold in the chemical compound Auranofin. In the following 7 days samples of hepatic bile were collected and analyzed by instrumental neutron activation analysis (INAA). After a 3-day irradiation with neutrons in the Research Reactor Geesthacht (FRG) and after a waiting time of 5–10 days, the limit of detection for gold was about 0.03 ng. The gold concentration in bile reached the maximum value (≈65 ng/ml) after about 16 hours and decreased with a biological half-life, first of 21 hours and later, in the end phase, of 6.5 days. Further elements were determined in the hepatic bile: Na, Ca, Fe, Co, Zn, Se, Br, Rb, Cs, Ba, Hg and sporadically K, Sc, Cr, Ni, Sb, La, Ce, Eu, Tb, Hf, Ta, Th. Some of these elements occurred in clusters. The blank values of the quartz ampoules and the precision, accuracy and limit of detection of these elements are given. The element concentrations found in bile are compared with those in plasma and classified after BRAUER.  相似文献   

3.
Neutron activation analysis of major and trace elements in crude petroleum   总被引:1,自引:0,他引:1  
We have determined the concentration of 25 trace elements in crude petroleum from seven Libyan oil fields by instrumental neutron activation analysis. Crude oil samples were irradiated with a thermal neutron dose rate of 1012 and 1013 n·cm–2·s–1 in the Tajoura research reactor. The concentration of U, Br, Mg, Cu, Na, V, Cl, Al, Mn and Ca is in a range of 0.015 to 84 ppm and that of sulphur of 0.12 to 1.8%. The elements Sc, Cr, Ni, Fe, Co, Zn, Ag, Se, Sb, Ba, Cs, Yb, Hf and Hg have a concentration range of 0.009 to 8747 ppb. The coefficients of variation are within 10%. The elements V and Ni occur as both porphyrin and non-porphyrin and the ratio of these two forms varies over a wide range. The V/Ni ratios are located between 0.17 and 6.67, which are comparable to the reported values for the crude oils from other countries.  相似文献   

4.
Eggshell material was used as low-cost and eco-friendly biosorbent for removal of 134Cs, 60Co and 152+154Eu radionuclides from aqueous solution. The eggshell material was calcined at 500 and 800 °C, and then characterized. Comparative studies on the natural and calcined eggshell for sorption of the three radionuclides were carried out. It was found that, the uptake is in the order: Eu(III) > Co(II) > Cs(I). Further, column chromatography was used in separation of 134Cs, 60Co and 152+154Eu using 0.15, 0.2 and 0.5 mol/l nitric acid, respectively. Eggshell material can be considered as a promising material for separation of radionuclides from radioactive waste solution.  相似文献   

5.
Instrumental neutron activation analysis has been used to determine 15 trace elements in twelve blood serum samples taken from healthy students at Bilkent University in Ankara. The method allowed the determination of Sc, Cr, Mn, Fe, Co, Zn, Se, Rb, Cs, Ce, Eu, Tb, Hf, Ta and Hg, which occur at the g.ml–1 to ng.ml–1 levels. There are no values reported for Tb, Hf, Ce, Eu and Ta before. The other results are compared with the values reported in the literature. Most are in the range of the reported values except for Fe, Zn, Se and Cs.  相似文献   

6.
In this paper we report the point of zero charge (pHzpc) of natural magnetite and its adsorptive properties with regard to alkali metal ions. It has been found that pHzpc of freshly ground, untreated magnetite is 6.5, decreasing, after treatment with HCl, to the value of pH 3.8. This discrepancy might be explained as a consequence of possible structure changes on the magnetite surface. Adsorption properties of magnetite with respect to Li+, Na+ and K+ ions in the concentration and pH ranges varying from 0.1 to 1.0 mol·dm?3 and 6.5 to 10, respectively, were examined. For the used chloride media used, the adsorption sequence obtained is Na+>K+>Li+.  相似文献   

7.
The concentrations of ten trace and dopant elements in GaAs semiconductor were determined by reactor neutron activation analysis after removal of As by evaporation of AsCl3. The retentions of the elements of interest were measured using radiotracers. The concentrations of doping elements (Te, Cr and Zn) in commercial GaAs samples were compared to the limit of detection of these elements to analyze the possibility to use NAA for concentration depth profiling measurements. The NAA results were compared with those of electrical measurements and SIMS and the discrepancies found are discussed.  相似文献   

8.
The content of trace elements in arsenic and antimony minerals from the Allchar mine, Macedonia, was determined by electrothermal atomic absorption spectrometry (ETAAS) and k0-instrumental neutron activation analysis (k0-INAA) after removal of arsenic and antimony. Their direct determination by ETAAS or k0-INAA in arsenic (realgar and orpiment) and antimony (stibnite) minerals is limited by strong matrix interferences from As and Sb. Successful elimination of both elements was realized by the extraction of their iodide complexes into toluene. It was found that the optimal conditions were triple extraction of arsenic into toluene from 6mol·L–1 HCl with addition of KI. Triple extraction of antimony was most successful in the system 4.5mol·L–1 H2SO4 and KI into toluene. In both cases, trace elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were then detected in the aqueous phase by ETAAS. The proposed procedures with ETAAS were checked by the method of standard additions and Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn determined in realgar, orpiment and stibnite. Using k0-INAA the trace elements Ba, Ce, Co, Cr, Cs, Fe, Hg, Sc, Tb, Th, U and Zn in realgar and orpiment were determined before and after As and Sb removal from the same aliquot of sample. The removal of both elements with KI into toluene was higher than 99.8% and no losses of trace elements were observed.  相似文献   

9.
Electromotive-force measurements of the cell $$Pt;H_2 (g, 1 atm)|HCl (y_A I), CsCl (y_B I)|AgCl;Ag$$ for five values of the ionic strength (I) between 0.1 and 3.0 mol-kg?1 and over the temperature range 5 to 50°C are reported. At I=1.0 and above, the activity coefficients of HCl are a distinctly non-linear function of solution composition. This behavior is satisfactorily accounted for in terms of specific ion interactions of the type H?Cs and H?Cl?Cs. The temperature variation of the Harned coefficient supports the suggestion of Robinson that the interaction H?Cs is insensitive to temperature changes.  相似文献   

10.
A very rapid method for the separation of molybdenum(VI) from neutron irradiated uranium and its fission products is described. The procedure is based on the selective extraction of molybdenum(VI) by a 0.1M solution of 2-hexylpyridine in benzene from 4M HCl+0.04M KSCN. Decontamination factors were estimated to be >104 for the radionuclides of niobium, zirconium, ruthenium, lanthanum, cerium, promethium, yttrium, strontium and barium.  相似文献   

11.
The thermochemistry of the reaction of the microsolvated Na+ such as [Na(H2O) n ; n?=?1?6]+, [Na(NH3) n ; n?=?1?6]+ and [Na(H2O) n (NH3) m ; n?+?m?=?2?6]+ with thymine (Thy), as an example of a reaction in the microcosmic environment, have been studied in this work, theoretically. It was found that the increase of the number of solvent molecules in the structure of microsolvated Na+ is accompanied by the decrease of the standard enthalpy (\(\Delta H_{r}^{^\circ }\)) and Gibbs free (\(\Delta G_{r}^{^\circ }\)) energies of the reaction (Thy?+?[Na(X) n ]+→Thy-Na(X) n + ; X?=?solvent molecule). Also, the calculations showed that the electronic intermolecular interaction (?Eint) between the Thy and microslovated Na+ decreased with the increase of solvent molecules. For the interaction of the [Na(H2O) n ; n?=?4, 5 and 6]+ ions with the Thy, there was the probability of forming of the hydrogen bond between water molecules in the structure of solvated Na+ and the Thy. The gas phase infrared (IR) spectra of the complexes of the microsolvated Na+ with the Thy for different values of n were calculated and compared with each other to follow the change in the frequency of the stretching vibration of the interaction path between the C=O group of the Thy and Na (O…Na) with n. Using the calculated values of \(\Delta G_{r}^{^\circ }\) of the reactions, the mole fractions of the complexes of microsolvated Na+ ions with the Thy were calculated at different humidity.  相似文献   

12.
A radiochemical separation method has been developed for the separation of platinum, gold and palladium from various matrices by thermal neutron activation analysis and employing substoichiometric extractions of Pt and Au with 2-mercaptobenzothiazole and Pd with isonitrosobenzoylacetone. Decontamination factors for the individual elements after separation was also studied and was found to be greater than 105 for most of the elements.  相似文献   

13.
We have investigated K+ collisions (200 to 1000 eV) under grazing incidence with partially alkalated (K, Cs) W(110) surfaces by energy analysis of the ejected electrons. Three different mechanisms for electron emission could be identified (1) Kinetic emission mainly confined to projectile energies greater than 300 eV, (2) Auger deexcitation of excited projectile valence states yielding electrons with energies up to about 2.9 eV and (3) Creation of inner shell vacancies (Cs(5p ?1) and K(3p ?1)) which gives rise to Auger type processes (OVV and MVV) and to the formation of autoionizing states of the type A (np 5 n′s n″l) (A=Alkali atom). The relative importance of the three mechanisms is studied as a function of the alkali coverage of the surface and of the projectile's energy.  相似文献   

14.
15.
Electromotive-force measurements of the cell $$Pt;H_2 \left( {g,1{\text{ }}atm} \right)|HCl\left( {{\text{m}}_A } \right),NaCl\left( {{\text{m}}_B } \right)|AgCl;Ag$$ have been made at temperatures between 5 and 45°C at values ofm A+m B of 0.1, 0.3809, 0.6729, and 0.8720 mole-kg?1. The activity coefficients of HCl in HCl/NaCl mixtures and the Harned coefficients α12 have been obtained. The change of α12 with total molality is consistent with the existence of binary interactions between H+ and Na+ ions. The linear variation of the relative partial molal heat content with the fraction of NaCl in the mixture suggests that an analog of the Harned rule exists for this thermodynamic quantity.  相似文献   

16.
Much attention has been devoted to Sn (IV) strongly retained on the TBP-Daiflon column from 2M HCl in extraction chromatography. The separations of Sn?Cu, Zn, As, Cd, Sb, Pb,113Sn-125Sb,113Sn-113mIn (113mIn milking) and Sn?Hg?Fe were successfully achieved without any contamination. In the separations, except for the last, only tin was retained separately on the column upon passing the mixed solution. The daughter indium was eluted with 0.5M HCl. In the last separation, iron was eluted with 0.5 M HCl, tin with 0.1M HCl and mercury with 2M HNO3, for these metals retained on the column. Radioactive tracers for tin, iron, mercury and antimony were used.  相似文献   

17.
New synthetic standard samples (SSB-1 and SSB-2), produced on the basis of phenol-formaldehyde resin in the shape of tablets are suggested. The samples are intended for INAA of biological materials. SSB-1 and SSB-2 samples contain Se, Cr, Au, Sb, Ag, Rb, Fe, Zn, Co and Ca, Ba, Hg, Sn, Br, Cs, Ni, Sc and Na. The concentrations of these elements are chosen so that the maximum statistical error of -quantum registration by the semiconductor detector should not exceed 3% when irradiating samples in a neutron flux of 1013 n·cm–2·s–1.  相似文献   

18.
Recycling of NADP+ using immobilized wholeEscherichia coli cells as source of respiratory chain, glucose-6-phosphate, and soluble yeast glucose-6-phosphate dehydrogenase (1.1.1.49) is described. NADP+ was recycled more than 10-fold. We demonstrated NADPH respiration at pH 5.8 inE. coli membrane vesicles. The respiratory chain was involved most probably in NADPH oxidation.
  1. The respiratory activity is localized at the level of the inner bacterial membrane. The active site for NADPH facing the cytoplasm.
  2. NADPH respiration is inhibited by 10 mM cyanide, similar to the conditions of inhibition of NADH respiration.
  3. NADPH dehydrogenase activity seems to be the limiting step of the respiratory chain:K M for NADPH respiration and NADPH dehydrogenase activity are similar. The pH optima for these two activities are also comparable (around pH 5.8). Furthermore, the following properties are rather in favor of a common NADH dehydrogenase and NADPH dehydrogenase activity (1.6.99.2).
o| li](1)|At saturating concentrations of NADH and NADPH, neither respiration nor dehydrogenase activities were additive. li](2)|Similar heat inactivation kinetics were observed for NADH and NADPH dehydrogenase-activity. Protection against heat inactivation was obtained for the two activities with NAD+, NADP+, NADH, and NADPH. All these results suggested the possibility of recycling of NADP+ under similar conditions to those previously described for NAD+ (Burstein et al., 1981). It becomes thus possible to use various NAD+ and NADP+-dependent dehydrogenases in enzyme technology.  相似文献   

19.
Instrumental neutron activation analysis was applied for the determination of trace elements in Canoparmelia texana species collected mnonpolluted areas of Atlantic Forest and in six sites of Santo André Municipality, SP, Brazil. Concentrations of As, Ba, Br, Ca, Cd, Cl, Cr, Cs, Co, Fe, K, La, Mn, Na, Rb, Sb, Sc, Se, U, and Zn were determined and comparisons were made between the results obtained in lichens from different sites.  相似文献   

20.
The rapid industrial development in regions of Mexico during recent years has had the side effect of introducing toxic metals, fertilizers, and pesticides into the ecosystem. Sediment cores were collected from eight locations around the Julian Adame-Alatorre dam located in the Municipality of Villanueva in the State of Zacatecas, México. The cores were analyzed for 32 major, trace, and rare earth elements (As, La, Lu, Nd, Sm, U, Yb, Ce, Co, Cr, Cs, Eu, Fe, Hf, Rb, Sb, Sc, Sr, Ta, Tb, Th, Zn, Zr, Al, Ba, Ca, Dy, K, Mn, Na, Ti, and V) in order to estimate the health risk. The samples were analyzed by instrument neutron activation analysis (INAA) using thermal neutron fluxes of 8 × 1013 and 5 × 1013 n cm−2 s−1 for short and long irradiations, respectively. The results of the contamination levels for elements such as As, Ba, Cr, Fe, Mn, Ta, V, and Zn were compared with the Mexican regulations and the guidelines of USEPA. Enrichment factors for quantified elements identified high As, Sb, Hf, and Cs contents using Fe as a crustal reference.  相似文献   

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