Taguchi, Shigeo; Miyauchi, Hironari*; Horigome, Kazushi; Yamamoto, Masahiko; Kuno, Takehiko
Bunseki Kagaku, 67(11), p.681 - 686, 2018/11
In thermal ionization mass spectrometry, de-gassing is one of the important treatments to release impurities of filaments and to minimize the influence of background. In this work, the effect of the surface change in the tungsten filament induced by the conductively heating treatment on uranium isotopic (U/U) measurement has been investigated. It was found that the conductively heating treatment of the filament has the effect of smoothing the surface of the filament and also has the effect of improving the deposition of the sample on the filament surface. As a result of either these effects, the precision of uranium isotopic (U/U) measurement was improved.
Saito, Kyoichi*; Asai, Shiho
Bunseki Kagaku, 66(11), p.771 - 782, 2017/11
Recovery and purification of rare metals, which are essential ingredients for highly functional materials, generally comes with operational difficulty. In this study, we have developed polymer adsorbents specially designed for highly-efficient adsorption of rare metal ions and exhibited their practical adsorption performances. Radiation-induced graft polymerization, one of the effective modification techniques for polymers, was employed for preparing the proposed adsorbents. Among such adsorbents, a 6-nylon fiber with nucleic-acid base, adenine, on the surface of the fiber demonstrated specific adsorption of ruthenium and palladium ions. In addition, a 6-nylon fiber with an extractant HDEHP (bis (2-ethylhexyl) phophoric acid) that has high affinity for lanthanides, achieved higher separation speed than a commercially available HDEHP-impregnated resin.
Bunseki Kagaku, 66(11), p.797 - 808, 2017/11
A new liquid-liquid extraction method, called the emulsion-flow method, has recently been developed at Japan Atomic Energy Agency (JAEA). The emulsion-flow method, where low cost, simplicity, high efficiency, compactness, safety, and eco-friendly go together, has attracted attention, and has been expected to bring innovation to liquid-liquid extraction technologies. Compared with conventional industrial apparatuses, an emulsion-flow apparatus successfully combines the lowest cost superior to a spray column and the highest performance (the highest efficiency and the highest processing speed) comparable to a centrifugal extractor. Furthermore, the emulsion-flow method can also be used for collecting particulate components by utilizing their aggregation onto a liquid-liquid interface and for purifying water polluted by oil with its remarkable phase-separating ability.
Yomogida, Takumi; Asai, Shiho; Saeki, Morihisa*; Hanzawa, Yukiko; Horita, Takuma; Esaka, Fumitaka; Oba, Hironori*; Kitatsuji, Yoshihiro
Bunseki Kagaku, 66(9), p.647 - 652, 2017/09
Palladium-107 is a long-lived fission product, which can be found in high-level radioactive liquid wastes (HLLW). Determination of the Pd contents in HLLW is essential to evaluate the long-term safety of HLLW repositories. However, the Pd content in HLLW has not been reported because of difficulties in pretreatment for the measurement. In this study, we investigated applicability of laser-induced photoreduction to HLLW solution: it enables a simple and non-contact separation of Pd. The results showed the recovery of 60% was achieved at the conditions: 40% ethanol, 20 min irradiation, 100 mJ of pulse energy. Additionally, major radionuclides and potentially interfering components in ICP-MS were removed from the simulated HLLW over a wide concentration range of Pd from 0.24 to 24 mg L, showing the applicability of the proposed separation technique to HLLW samples.
Bunseki Kagaku, 66(7), p.531 - 532, 2017/07
This paper summarizes the author's doctoral thesis on analytical chemistry. In this study, the ionic liquid (IL) extraction of various metal(II, III) complexes with macrocyclic and anionic chelating ligands has been investigated to clarify the solvent effect of ILs and to demonstrate the specificity and superiority of the IL extraction systems over conventional ones. The evaluation of the extraction equilibrium of Eu(III) with 2-thenoyltrifluoroacetone (Htta) in 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TfN]) and time-resolved laser-induced fluorescence spectroscopy revealed the specific solute-solvent interactions between Eu(tta) and [Cmim][TfN]. The IL synergistic extraction with Htta and -dicyclohexano-18-crown-6 was developed. The extractability of lighter lanthanides(III) was remarkably enhanced by a synergistic effect of crown ethers. A macrocyclic ligand (HDA18C6) composed of diaza-18-crown-6 and two 4-acyl-5-pyrazolones was synthesized for the extraction of Sr(II). The extraction performance of HDA18C6 was significantly enhanced only in [Cmim][TfN] by the intramolecular cooperative effect.
Saito, Kyoichi*; Kojima, Takashi*; Asai, Shiho
Bunseki Kagaku, 66(4), p.233 - 242, 2017/04
Insoluble cobalt ferrocyanide and sodium titanate specifically capture cesium and strontium ions, respectively, in water contaminated with radionuclides which is found in Fukushima Daiichi NPP. The inorganic compounds used in this study were formed as precipitates in the polymer chain grafted onto a commercially available 6-nylon fiber using radiation-induced graft polymerization. An impregnation structure with the precipitates entangled by the grafted polymer chain through an electrostatic interaction via multipoints was indicated. The resultant insoluble cobalt ferrocyanide- or sodium titanate-impregnated fiber exhibited a higher adsorption rate and adsorption capacity per gram of the inorganic compound for cesium or strontium ions in seawater than conventional granular adsorbents.
Takagai, Yoshitaka*; Furukawa, Makoto*; Kameo, Yutaka; Matsueda, Makoto; Suzuki, Katsuhiko*
Bunseki Kagaku, 66(4), p.223 - 231, 2017/04
no abstracts in English
Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*
Bunseki Kagaku, 66(4), p.251 - 261, 2017/04
no abstracts in English
Sanada, Yukihisa; Ishizaki, Azusa; Nishizawa, Yukiyasu; Urabe, Yoshimi*
Bunseki Kagaku, 66(3), p.149 - 162, 2017/03
The Great East Japan Earthquake that occurred on 11 March 2011 generated a series of large tsunami waves that caused serious damage to the Fukushima Dai-ichi Nuclear Power Station, following which a large amount of radioactive material was discharged from the nuclear power plant into the environment. The airborne radiation measurement using a manned helicopter was applied to measure the radiation distribution immediately after accident of the Fukushima Dai-ichi Nuclear Power Station as technique to quickly measure the radiation distribution in the wide area. In Japan, this technique was researched and developed in the 1980s. However, this technique and system were not applied immediately after the accident because standardization of analysis was not established and the Japanese system became deteriorated. This technique is important for post-accident of nuclear facility. We summarized the methods of the airborne radiation measurement using a manned helicopter. In addition, measurement results of dose rate distribution at the Fukushima Dai-ichi Nuclear Power Station was shown in this paper.
Horita, Takuma; Asai, Shiho; Konda, Miki; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Kitatsuji, Yoshihiro
Bunseki Kagaku, 66(3), p.189 - 193, 2017/03
A Sr-selective adsorption fiber was prepared for rapid analysis of Sr content by using radiation-induced emulsion graft polymerization and subsequent chemical modification. A polyethylene fiber with a diameter of 13 m was first immersed in a methanol solution of an epoxy-group-containing vinyl monomer, glycidyl methacrylate (GMA), and polyoxyethylene sorbitol ester (Tween20) as a surfactant for graft-polymerization of GMA. Octadecylamine was then bound to a polymer chain extending from the fiber surface providing hydrophobicity to the polymer chain. Dicyclohexano-18-crown-6 (DCH18C6) was finally impregnated onto the polymer chain via a hydrophobic interaction between the octadecyl moiety of the polymer chain and the cyclohexyl moiety of DCH18C6. The fiber surface structure, characterized by DCH18C6 molecules loosely entangled with polymer chains, afforded realizes the rapid and selective adsorption of Sr ions with an adsorption rate approximately 100 times higher than that of a commercially available Sr-selective resin (Sr Resin).
Bunseki Kagaku, 66(2), p.123 - 124, 2017/02
no abstracts in English
Yonezawa, Chushiro*; Shirono, Katsuhiro*; Haraga, Tomoko
Bunseki Kagaku, 66(1), p.27 - 37, 2017/01
no abstracts in English
Hirao, Norie; Shimoyama, Iwao; Baba, Yuji; Izumi, Toshinori; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi
Bunseki Kagaku, 65(5), p.259 - 266, 2016/05
After the Fukushima nuclear plant accident, radiocesium was strongly fixed to clay minerals in the soil. Some dry methods with heating are being developed to remove radiocesium from the soil. In this work, we propose a new dry method that combines heat treatment in vacuum and molten salts to reduce the processing temperature in dry methods. Vermiculite saturated with non-radioactive Cs was heated in vacuum, and Cs contents in the vermiculite were compared before and after heating using X-ray photoelectron spectroscopy. Approximately 40% of cesium were removed by heating at 800C for three minutes when only vermiculite was heated. Approximately 70% of cesium were removed by heating at 450C for three minutes when vermiculite was heated with NaCl/CaCl mixed salts. Based on these results, this method is expected to reduce temperature and increase efficiency on dry methods for cesium removal from clay minerals.
Ekisupato Oyo Kagaku Sirizu; Kiki Bunseki, p.119 - 135, 2015/09
Bulk analysis has been conventionally used for measuring solid materials. In contrast, surface analysis is extensively used for analyzing chemical compositions and chemical states of solid surface. The surface compositions often differ from those of bulk materials. Recently, doping of impurity elements and deposition of thin films on the surface of the materials are key techniques to fabricate functional materials. Therefore, surface analysis becomes important to characterize such materials. In this paper, the principle and feature of some surface analytical techniques are described.
Kushita, Kohei; Atarashi-Andoh, Mariko; Amano, Hikaru*
Bunseki Kagaku, 63(11), p.867 - 871, 2014/11
We report here the study of activated gold for the estimation of neutron dose in the environment in the case of JCO criticality accident happened in Tokai, Japan, in 1999. We collected and analyzed 16 gold samples, such as ring, coin or necklace stored at residents houses in the range from 168 to 568 m from the accident place of JCO. They gave activities from 91.9 to 0.322 Bq/g-Au as standardized values at 06:15, Oct. 1, 1999, when the criticality reaction had ceased after 20 hours of continuation. The induced radioactivity of gold samples showed a good correlation as a power function of distance. The induced radioactivity of gold is discussed with reference data to estimate dose equivalent in the environment around JCO. This paper gives an example showing the usefulness of gold in the field of nuclear and radiation studies and applications.
Ozu, Akira; Esaka, Fumitaka; Yasuda, Kenichiro
Bunseki Kagaku, 63(7), p.609 - 617, 2014/07
Decay ratios of the laser-induced fluorescence emitted from five types of asbestos and six types of building materials in the broad wavelength region from 350 to 700 nm were investigated by using an ultraviolet laser pulse of 266 nm. Dependence of the decay ratios on the wavelength were compared, and evaluated in an attempt to numerically discriminate asbestos from the other building materials. It was observed that the decay ratios of each material were not constant over the wavelength region and varied in the wavelength over time. The fluorescence of asbestos and the building materials except for rock fiber at above 500 nm decayed faster than that at below 500 nm. The wavelength region from 405 to 420 nm was found optimum to identify types of asbestos and to discriminate asbestos from the building materials by comparing the decay ratio at the delay time of 10 ns after the incidence of laser pulse.
Yasuda, Mari; Nebashi, Koji*; Yonekawa, Naoki; Yasumatsu, Takuyo*; Kameo, Yutaka
Bunseki Kagaku, 63(4), p.345 - 350, 2014/04
A simple analytical method was developed for the determination of Cd in the treated wastewater arising from Advanced Liquid Processing System (ALPS) at the Fukushima-1 nuclear power plant. Cadmium in the wastewater containing sea salt was effectively purified by an anion-exchange procedure. It was found that more than 97% of Cd were recovered by the present procedure from a sample solution of 2M HCl. Since a radioactivity standard solution of Cd was difficult to purchase from venders, beta-ray counting efficiency for Cd was estimated using 99Tc and 36Cl standard solutions. Minimum detectable activity was calculated to be 0.003 Bq mL. The present analytical method would be well suited for a rapid and simple determination of Cd in wastewater treated by ALPS.
Hirao, Norie; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao
Bunseki Kagaku, 63(1), p.53 - 58, 2014/01
A method for quick and real-time observations of a solid surface at nanometer scale is described. The principle of the method is as follows. Soft X-rays from a synchrotron light source are irradiated on a solid surface and the total photoelectrons are expanded and focused on a screen using electrostatic lenses. When the energy of X-rays is scanned and the brightness is plotted, we can obtain micro X-ray absorption (micro-XAFS) spectra in all regions of the image. The spacial resolution of the method was 40 nm. In order to more quickly observe a microscopic image and measure micro-XAFS spectra, the soft X-rays from the bending magnet were focused using a newly developed poly-capillary. As a result, the photon flux of 3 keV X-rays was increased about 60 time higher than that before the focusing. Using focused X-rays, we succeeded in observing one image at 10 ms for a bulk sample. We have also tried to shorten the measuring time of the micro-XAFS spectrum. For a Si-SiO sample, it has been demonstrated that micro-XAFS spectra in all regions of an image can be obtained within 1 min. It is concluded that real-time observations of chemical-states at nanometer scale are possible by the present method.
Korekara No Kankyu Bunseki Kagaku Nyumon, p.107 - 114, 2013/11
The purpose, principle and methods of environmental radioactivity measurement are explained in this paper.
Kameo, Yutaka; Ishimori, Kenichiro; Shimada, Asako; Takahashi, Kuniaki
Bunseki Kagaku, 61(10), p.845 - 849, 2012/10
A simple determination method was developed to measure I in low level radioactive liquid waste solidified with bitumen. A simulated bituminized product sample was cut to 0.02 g pieces, subsequently these pieces and sodium carbonate were heated in an electric furnace. This procedure could well decompose the bituminized sample without volatilizing I. Sixty to seventy percent of I was recovered by a solid phase extraction disk from a solution containing the decomposed sample. A dynamic reaction cell inductively coupled plasma mass spectrometer was applied to measure I, and as a result, detection limit of I was reduced to by a factor of about 6 comparing with conventional ICP-MS measurement. Determined radioactivity concentration for the simulated bituminized sample containing I was good agreement with expected value within 6% error.