Elution of 235U fission products through a calcined hydrotalcite-packed column

Calcined hydrotalcite packed columns were utilized to sorb ²³⁵U fission products and their decay products. The elution behavior of some radionuclides was studied after washing the columns, either with distilled water or 0.5% NaCl solution. Afterwards, fission products and their decay products were eluted using 0.5% NaCl solution. It was found that no matter the washing process, ^99mTc, the b^--decay product of ⁹⁹Mo, was easily separated from ⁹⁹Mo which was strongly retained on the hydrotalcite. ¹³²I, the b^--decay product of ¹³²Te, was eluted slowly and was separated from ¹³²Te which was retained on the column. ¹³¹I and ¹⁴⁰Ba were eluted together with ^99mTc and ¹³²I, although in smaller proportions.     

Adsorption of fission products on a metal surface in nitric acid solutions: Radiochemical study using a multitracer

Adsorption behavior of fission products in nitric acid solution on various alloys and metals was studied by using a multitracer produced by neutron irradiation of UO₂. The adsorption behavior of the fission products ⁹⁹Mo, ¹³¹I, ¹³²Te, ¹⁴⁰La, and ¹⁴³Ce, and ²³⁹Np was simultaneously studied. Some chemical decontamination tests were also examined. Clear adsorption of ⁹⁹Mo, ¹³¹I, and ¹³²Te was observed, whereas adsorption of ¹⁴⁰La, ¹⁴³Ce, and ²³⁹Np was not. The adsorption characteristics were discussed by considering anion-exchange reaction and surface complexation.     

Rapid determination of 89Sr and 90Sr in radioactive waste using Sr extraction disk and beta-ray spectrometer

A rapid determination method in which beta-ray spectrometry was combined with solid phase extraction using Sr Rad Disk was developed for the determination of ⁸⁹Sr and ⁹⁰Sr in low-level radioactive waste. Various amounts of ⁸⁹Sr, ⁹⁰Sr, and ⁹⁰Y retained by the Sr Rad Disk was measured by a beta-ray spectrometer, and it was found that both ⁸⁹Sr and ⁹⁰Sr were simultaneously determined with <30% error (2σ) at ⁸⁹Sr/⁹⁰Sr radioactivity ratio of 0.3 to 45. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear facilities in Japan Atomic Energy Agency. Strontium was simply separated from interfering nuclides such as ¹³⁷Cs and ¹⁵⁴Eu, and matrix components by the Sr Rad Disk, and the results obtained by beta-ray spectrometry was in good agreement with that of the conventional analysis.     

A Highly Selective and Sensitive Fluorescent Chemosensor for Detection of Al3+ in Totally Aqueous Media

A fluorescent chemosensor ( 1 ) based on 2‐hydroxy‐1‐naphthaldehyde Schiff‐base was developed for the detection of Al³⁺ in 100% aqueous solution. Upon addition of Al³⁺, a significant fluorescence enhancement was observed, which was not affected by other metal ions including Na⁺, K⁺, Ca²⁺, Mg²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cr³⁺, Ag⁺, Pb²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Fe²⁺ and Fe³⁺ under weak acid conditions. Moreover, the specific response to Al³⁺ was visible under natural light. The binding mode between 1 and Al³⁺ was clarified by ESI‐MS and ¹H NMR.     

Preparation of manganese-53

The nuclide⁵³Mn was produced by the following three nuclear reactions,⁵²Cr(d, n)⁵³Mn,⁵¹V(³He n)⁵³Mn and⁵⁰Cr(α, n), (α, p)⁵³Mn. Enriched⁵²Cr and⁵⁰Cr metal targets were prepared on copper plate holder by electrodeposition. The commercially available natural vanadium foil was used for the⁵¹V(³He, n)⁵³Mn reaction. Each target was bombarded in a cyclotron. Manganese was extracted and purified without using carrier from the bombarded targets by anion and cation exchanges and solvent extraction. The isotopic ratio⁵³Mn/⁵⁵Mn was measured by mass spectrometry and the amount of⁵⁵Mn was determined by neutron activation analysis. The activity of⁵³Mn obtained was 7 dpm by 750 millicoulombs in³He bombardment (E³He=20 MeV). The activity due to by-product⁵⁴Mn was about several thousands times higher than that of⁵³Mn in³He and deuteron bombardments, which were produced through⁵¹V(³He, γ)⁵⁴Mn and⁵³Cr(d, n)⁵⁴Mn. In alpha bombardment (E_α=15 MeV), the activity of⁵³Mn produced was 8 dpm by 95 millicoulombs. The activity ratio, dpm⁵⁴Mn/dpm⁵³Mn, was about 3, and this ratio was the best one among the results so far obtained.     

负载型纳米二氧化钛对重金属离子吸附性能的研究

采用溶胶-凝胶法制备二氧化钛溶胶, 将其浸渍在硅胶上, 合成了负载型纳米二氧化钛材料, 以X射线衍射(XRD)、扫描电镜(SEM)等手段对其进行了表征. 以ICP-AES为检测手段, 系统地研究了负载型纳米TiO₂材料对重金属离子Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的吸附性能. 结果表明, 在pH 8～9范围内, 所研究的重金属离子均可被定量富集, 吸附的金属离子可用0.5 mol/L的HNO₃完全解脱. 负载型纳米二氧化钛对Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的静态吸附容量分别为8.3, 13.1, 12.6和5.1 mg/g, 与未负载的纳米二氧化钛相近. 将其应用于环境标准样品中Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的分离富集与测定, 结果满意.     

Fluorescence Enhancement of Rare Earths by Yttrium and its Application

Abstract

A study of the enhancement effect on the fluorescence intensity of the Eu³⁺–-thenoyltrifluoroacetone (TTA)–-cetyltri–-methylammonium bromide (CTMAB) and the Dy³⁺ pyrocatechol–-3,5-disulphonic acid (Tiron) systems by Y³⁺has been carried out. In the presence of yttrium the fluorescence intensity of the systems was enhanced by a factor of about 100 and 15, respectively. The fluorescence intensity was a linear function of the concentration of europium or dysprosium in the range 1.0 × 10^?10–-1.0 × 10^?8mol dm^?3 and 8.0 × 10^?8–-9.0 × 10^?6mol dm^?3, respectively. The detection limit was 1.0 × 10^?11mol dm^?3 and 1.0 × 10^?10mol dm^?3, respectively. The standard addition method was used for the determination of europium or dysprosium in rare earth oxides and gave satisfactory results. The mechanism of enhanced fluorescence was proposed.     

188Rhenium-glucoheptonate: A radiopharmaceutical for intravascular radiation therapy

The preparation of ¹⁸⁸Re-glucoheptonate (GH) is described using ¹⁸⁸Re, which was obtained from an alumina based ¹⁸⁸W/¹⁸⁸Re generator. The dependence of the radiolabeling yields of ¹⁸⁸Re-GH on reducing agent concentration, GH concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of ¹⁸⁸Re-GH was ~99%. The ITLC technique was employed to monitor the different species formed. A biodistribution study of ¹⁸⁸Re-GH was carried out in rats and compared to the biological behavior of ^99mTc-GH.     

Ionophores in Rubidium Ion‐Selective Membrane Electrodes

Binaphthyl‐based crown ethers incorporating anthraquinone, benzoquinone, and 1,4‐dimethoxybezene have been synthesized and tested for Rb⁺ selective ionophores in the poly(vinyl chloride) (PVC) membrane. The membrane containing NPOE gave a better Rb⁺ selectivity than those containing either DOA or BPPA as a plasticizer. The response was linear within the concentration range of 1.0×10^?5–1.0×10^?1 M and the slope was 54.7±0.5 mV/dec. The detection limit was determined to be 9.0×10^?6 M and the optimum pH range of the membrane was 6.0–9.0. The ISE membrane exhibits good selectivity for Rb⁺ over ammonium, alkali metal, and alkaline earth metal ions. Selectivity coefficients for the other metal ions, log K^Pot were ?2.5 for Li⁺, ?2.4 for Na⁺, ?2.0 for H⁺, ?1.0 for K⁺, ?1.2 for Cs⁺, ?1.6 for NH₄⁺, ?4.5 for Mg²⁺, ?5.0 for Ca²⁺,?4.9 for Ba²⁺. The lifetime of the membrane was about one month.     

Simultaneous determination of210Bi and210Po on pine needles by solvent extraction and liquid scintillation counting

A determination procedure has been developed for²¹⁰Bi and²¹⁰Po in environmental samples and was applied for pine needles. Bismuth-210 and²¹⁰Po separated from the parent nuclide²¹⁰Pb as BiOCl precipitate were extracted simultaneously by TOPO/toluene containing PPO and POPOP. The separation of²¹⁰Bi and²¹⁰Po from²¹⁰Pb was almost satisfactory. The activity of²¹⁰Bi+²¹⁰Po in the TOPO/toluene was measured periodically by liquid scintillation counting for about 20 days after separation. The time course of the decreasing pattern of the activity was determined by the initial activity ratio²¹⁰Po/²¹⁰Bi. The decreasing pattern of the activity was compared with theoretical patterns, and best estimates for²¹⁰Po and²¹⁰Bi were obtained by non-linear least-squares fitting. The activities of²¹⁰Bi and²¹⁰Po were determined for one-year and two-year old pine needles fro the same pine tree, and weathering half-time and deposition rate of these nuclides was discussed.     

Anthropogenic radiotracers assessment as tool to environmental compliance rules and management

A framework, within models and studies can be applied, to develop coherent and logical environmental impact management methodologies for ionizing radiation, is essential. A number of components, which form the basis for such a system, included the dilution factor for radioactive liquid effluent releases. In this study we established a strategic, fast and cheap methodology to estimate the dilution factor for the release of liquid radioactive effluents at IPEN. The radioisotopes ³H, ⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn, and ¹³⁷Cs, generated in the routine operation of the Research Reactor IEA-R1, were used as radiotracers. The generated liquid radioactive effluent was stored in a 300 m³ capacity tank. The initial concentration of its present radioisotopes were determined. A planned release of effluent from the storage tank was carried-out. Simultaneously, the sampling was made upstream of the storage tank discharge point and the concentration ³H, ⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn and ¹³⁷Cs in the mix sewerage system discharge point E1 at IPEN were monitored. The estimated dilution factor of discharge point of the aqueous effluent for ³H was 4.3 and 7.4, ⁵⁴Mn was12 and 16.1, ⁶⁰Co was 12.6 and 14.2, ⁶⁵Zn was 12 and 27.9 and ¹³⁷Cs was 6.2 and 13.9, respectively.     

Specific Uphill Transport of Zinc as Zn(SCN)42− Ion using Na+-Dicyclohexyl-18-Crown-6 as Carrier

Sodium-dicyclohexyl- 18-crown-6 complex cation was used as carrier for the uphill transport of zinc as Zn(SCN)₄^2? complex anion. By using L-cysteine as a metal ion acceptor in the receiving phase at the optimized pH of 7.6, the amount of zinc transport through the liquid membrane after 90 min was 97.2 ± 1.0%. The selectivity and efficiency of zinc transport from aqueous solutions containing equimolar mixtures of Ag⁺, Cd²⁺ Co²⁺, Cu²⁺, Fe²⁺, Ni²⁺, Pb²⁺, Pd²⁺, Sr²⁺, Bi³⁺, Cr³⁺ and Fe³⁺ ions was investigated. In the presence of NH₂OH.HCl as a suitable masking agent in the source phase, the interfering effect of Cu²⁺ and Pb²⁺ ions was diminished drastically.     

Determination of hydrogen ion by ion chromatography (IC) with sulfonated cation-exchange resin as the stationary phase and aqueous EDTA (ethylenediamine-N,N,N′,N′-tetraacetic acid) solution as the mobile phase

An ion chromatographic (IC) method has been developed for determination of hydrogen ion (H⁺). It is based on the use of sulfonated cation-exchange resin as stationary phase, aqueous ethylenediamine-N,N,N′,N′-tetraacetic acid (dipotassium salt, EDTA-2K, written as K₂H₂Y) solution as mobile phase, and conductivity for detection. H⁺ was separated mainly by cation-exchange, but its elution was accelerated by the presence of EDTA. The order of elution for the model cations was H⁺ > Li⁺ > Na⁺ > NH₄ ⁺ > Ca²⁺ > > Mg²⁺. A sharp and highly symmetrical peak was obtained for H⁺ and this was attributed to the capacity of H₂Y₂ ^2– to receive and bind H⁺. H⁺ was detected conductiometrically and detector response (reduction in conductivity as a result of H⁺+H₂Y^2–→H₃Y^–) was linearly proportional to the concentration of H⁺ in the sample. The detection limit for H⁺ with this IC system was better than 4.7 μmol L^–1. A significant advantage of this method was the ability to separate and determine, in one step, H⁺ and other cations. The successful determination of H⁺ and other cation species in real acid-rain samples demonstrated the usefulness of this method.     

Mechanistic Features of the TiO2 Heterogeneous Photocatalysis of Arsenic and Uranyl Nitrate in Aqueous Suspensions Studied by the Stopped‐Flow Technique

The dynamics of the transfer of electrons stored in TiO₂ nanoparticles to As^III, As^V, and uranyl nitrate in water was investigated by using the stopped‐flow technique. Suspensions of TiO₂ nanoparticles with stored trapped electrons (e_trap^?) were mixed with solutions of acceptor species to evaluate the reactivity by following the temporal evolution of e_trap^? by the decrease in the absorbance at λ=600 nm. The results indicate that As^V and As^III cannot be reduced by e_trap^? under the reaction conditions. In addition, it was observed that the presence of As^V and As^III strongly modified the reaction rate between O₂ and e_trap^?: an increase in the rate was observed if As^V was present and a decrease in the rate was observed in the presence of As^III. In contrast with the As system, U^VI was observed to react easily with e_trap^? and U^IV formation was observed spectroscopically at λ=650 nm. The possible competence of U^VI and NO₃^? for their reduction by e_trap^? was analyzed. The inhibition of the U^VI photocatalytic reduction by O₂ could be attributed to the fast oxidation of U^V and/or U^IV.     

Selective Recovery of Nonferrous Metal Cations from Wastewater with Weakly Basic Anion Exchangers

Selective recovery of transition metals (Ni^{2 +}, Cu^{2 +}, and Cr^{2 +}) with weakly basic anion exchangers from aqueous solutions simulating naturally mineralized water was studied. The exchange capacity of anion exchangers for these cations was determined. The technique for efficient resin regeneration was developed.     

Radiochemical separation of99Mo from natural uranium irradiated with thermal neutrons

⁹⁹Mo was separated from uranium and insoluble fission product hydroxides. More than 98% of⁹⁹Mo radioactivity was extracted with bis (2-ethylhexyl)phosphoric acid. The organic phase was washed and⁹⁹Mo was back-extracted from the organic phase with NH₄OH solution. The percent recovery from the organic phase was 91% and the purity of⁹⁹Mo was more than 99%. Pure^99mTc was also extracted from the organic phase with a saline solution. Reversed-phase partition chromatography was used for the purification of⁹⁹Mo from¹³¹I and other fission products (10% HDEHP on kieselguhr bed).¹³¹I and other isotopes were quantitatively eluted with 0.1M H₂SO₄,⁹⁹Mo was eluted using a mixture of 0.5 M HCl and 30% H₂O₂.     

Effect of environmental conditions on the sorption of radiocobalt from aqueous solution to treated eggshell as biosorbent

Carbonate hydroxylapatite (CHAP), prepared from eggshell waste, was used to remove ⁶⁰Co(II) from aqueous solutions. The sorption of ⁶⁰Co(II) on CHAP as a function of contact time, pH, ionic strength and foreign ions in the absence and presence of humic acid and fulvic acid under ambient conditions was studied. The sorption of ⁶⁰Co(II) on CHAP was strongly dependent on pH and ionic strength. The thermodynamic parameters (ΔH ⁰, ΔS ⁰, ΔG ⁰) of ⁶⁰Co(II) sorption on CHAP were calculated from the temperature-dependent sorption isotherms, and the results indicated that the sorption process of ⁶⁰Co(II) on CHAP was endothermic and spontaneous. At low pH, the sorption of ⁶⁰Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na⁺/H⁺ on CHAP surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. Experimental results also indicated that CHAP was a suitable low-cost adsorbent for pre-concentration and solidification of ⁶⁰Co(II) from large volumes of aqueous solutions.     

Chromo-chemodosimetric detection for Fe2+ by Fenton reagent-induced chromophore-decolorizing of halogenated phenolsulfonphthalein derivatives

A commercially-available sulfonphthalein derivative was demonstrated to be a chemodosimeter for Fe²⁺ and its sensing behavior was further investigated by UV-vis spectroscopy in aqueous media under the optimum conditions. In the presence of chlorophenol red (CPR) and H₂O₂, the absorption maximum at 435 nm decreased upon addition of Fe²⁺, resulting in a significant color change of the CPR solution from yellow to colorless. The chemosensor system did not show significant responses to a series of other metal ions including Al³⁺, Zn²⁺, Cd²⁺, Hg²⁺, Mn²⁺, Co²⁺, Fe³⁺, Ni²⁺, Cu²⁺, La³⁺, Ce⁴⁺, Th⁴⁺, Pd²⁺, Pb²⁺, Sb³⁺, Cr³⁺, Au³⁺, Ag⁺, Nd³⁺, Sm³⁺, alkali and alkaline earth metal cations, allowing for highly selective naked-eye detection of Fe²⁺. Quantitative analysis was carried out kinetically for practicable the Fe²⁺ assay when either fixed time method or the initial rate method was applied. When the detecting time was set, the decrease of absorbance signal was linear with Fe²⁺ concentration in the range of 0 to 7.50 × 10^?5 mol L^?1 and the regression equation was ΔA = 0.00759 + 0.00593C _Fe with a correlation coefficient r = 0.9953. The chemodosimetric system has employed an irreversible Fenton reagent-promoted oxidation of the CPR free chromophore and the hydroxyl radicals were generated in the presence of both Fe²⁺ and hydrogen peroxide. The mechanistic interpretation of the signaling process was partially confirmed by the radical scavenging experiment and the FT-IR analysis of the intermediates formed at different reaction periods.     

Uranium analysis in urine by inductively coupled plasma dynamic reaction cell mass spectrometry

Urine uranium concentrations are the best biological indicator for identifying exposure to depleted uranium (DU). Internal exposure to DU causes an increased amount of urine uranium and a decreased ratio of ²³⁵U/²³⁸U in urine samples, resulting in measurements that vary between 0.00725 and 0.002 (i.e., natural and depleted uraniums ²³⁵U/²³⁸U ratios, respectively). A method based on inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) was utilized to identify DU in urine by measuring the quantity of total U and the ²³⁵U/²³⁸U ratio. The quantitative analysis was achieved using ²³³U as an internal standard. The analysis was performed both with and without the reaction gas oxygen. The reaction gas converted ionized ²³⁵U⁺ and ²³⁸U⁺ into ²³⁵UO₂⁺ (m/z=267) and ²³⁸UO₂⁺ (m/z=270). This conversion was determined to be over 90% efficient. A polyatomic interference at m/z 234.8 was successfully removed from the ²³⁵U signal under either DRC operating conditions (with or without oxygen as a reaction gas). The method was validated with 15 urine samples of known uranium compositions. The method detection limit for quantification was determined to be 0.1 pg U mL^–1 urine and an average coefficient of variation (CV) of 1–2% within the sample measurements. The method detection limit for determining ²³⁵U/²³⁸U ratio was 3.0 pg U mL^–1 urine. An additional 21 patient samples were analyzed with no information about medical history. The measured ²³⁵U/²³⁸U ratio within the urine samples correctly identified the presence or absence of internal DU exposure in all 21 patients.The opinions and assertions expressed herein are those of the authors and are not to be construed as official or as representing the views of the Armed Forces Institute of Pathology, the Department of the Army, or the Department of Defense