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Journal Articles

Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

 Times Cited Count:2 Percentile:33.17(Chemistry, Inorganic & Nuclear)

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$$_{2}$$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$$_{2}$$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$$_{2}$$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

Journal Articles

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

 Times Cited Count:1 Percentile:17.98(Nuclear Science & Technology)

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive $$^{137}$$Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of $$^{137}$$Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of $$^{137}$$Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of $$^{137}$$Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of $$^{137}$$Cs can be confirmed in the normally existing gamma-scanning room or not.

Journal Articles

Radiation-induced degradation of aqueous 2-chlorophenol assisted by zeolites

Kumagai, Yuta; Kimura, Atsushi*; Taguchi, Mitsumasa*; Watanabe, Masayuki

Journal of Radioanalytical and Nuclear Chemistry, 316(1), p.341 - 348, 2018/04

 Times Cited Count:1 Percentile:17.98(Chemistry, Analytical)

We studied effect of adsorption and condensation by zeolites on radiation-induced degradation of aqueous 2-chlorophenol (2-ClPh). This study aims to demonstrate that the solid-phase extraction using zeolites has potential advantage in treatments of aqueous organic pollutants. Among three zeolites examined in this study, a mordenite type zeolite (HMOR) that has a high Si to Al ratio (127 $$pm$$ 3) exhibited preferable performance as the matrix for the 2-ClPh degradation. HMOR adsorbed far more 2-ClPh than the other zeolites, which have lower Si/Al ratios. The irradiation of HMOR induced degradation of adsorbed 2-ClPh into Cl$$^{-}$$ and organic by-products. We found a significant increase in Cl$$^{-}$$ production by HMOR. The yield of Cl$$^{-}$$ production in the presence of HMOR was as high as the yield in aqueous solution of 2-ClPh at a concentration 10 times higher. The increased Cl$$^{-}$$ production indicates that the high concentration of adsorbed 2-ClPh led to effective use of the adsorbed energy of HMOR.

Journal Articles

Chemical states of trace-level strontium adsorbed on layered oxide by XPS and XANES under total reflection condition

Baba, Yuji; Shimoyama, Iwao

Photon Factory Activity Report 2016, 2 Pages, 2017/00

In order to elucidate the adsorption states of radioactive Sr-90 in soil, chemical bonding states of non-radioactive strontium adsorbed on layered oxide (mica) have been investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy. Since the number of atoms in radioactive Sr-90 is extremely small, the XPS and XANES were measured under total reflection condition of the incident X-rays. The detection limit in total reflection XPS was about 150 pg/cm$$^{2}$$, which corresponds to 300 Bq of Sr-90. The Sr 2p$$_{3/2}$$ core-level energy in XPS shifted to lower energy with the decrease in the thickness of Sr layer. Also, the Sr 2p$$_{3/2}$$ $$rightarrow$$ Sr 4d$$^{*}$$ resonance energy in XANES shifts to lower energy with the decrease in the thickness. On the basis of a simple point charge model, it was elucidated that the chemical bond between Sr and mica surface becomes ionic with the decrease in the adsorbed amount of strontium.

Journal Articles

Diffusion and adsorption of uranyl ion in clays; Molecular dynamics study

Arima, Tatsumi*; Idemitsu, Kazuya*; Inagaki, Yaohiro*; Kawamura, Katsuyuki*; Tachi, Yukio; Yotsuji, Kenji

Progress in Nuclear Energy, 92, p.286 - 297, 2016/09

 Times Cited Count:6 Percentile:61.4(Nuclear Science & Technology)

Diffusion and adsorption behavior of uranyl (UO$$_2^{2+}$$) species is important for the performance assessment of radioactive waste disposal. The diffusion behaviors of UO$$_2^{2+}$$, K$$^{+}$$, CO$$_3^{2-}$$ and Cl$$^{-}$$ and H$$_{2}$$O in the aqueous solutions were evaluated by molecular dynamics (MD) calculations. The diffusion coefficient (De) of UO$$_2^{2+}$$ is the smallest and is 26% less than the self-diffusion coefficient of H$$_{2}$$O. For the aqueous solution with high concentration of carbonate ions, uranyl carbonate complexes: UO$$_{2}$$CO$$_{3}$$ and UO$$_{2}$$(CO$$_{3}$$)$$^{2-}$$ can be observed. For the clay (montmorillonite or illite)-aqueous solution systems, the adsorption and diffusion behaviors of UO$$_2^{2+}$$ and K$$^{+}$$ were evaluated by MD calculations. The distribution coefficients (Kd) increase with the layer charge of clay, and Kd of UO$$_2^{2+}$$ might be smaller than that of K$$^{+}$$. Further, their two-dimensional diffusion coefficients were relatively small in the adsorption layer and were extremely small for illite with higher layer charge.

Journal Articles

Effects of gamma-ray irradiation on spontaneous potential of stainless steel in zeolite-containing diluted artificial seawater

Kato, Chiaki; Sato, Tomonori; Ueno, Fumiyoshi; Yamagishi, Isao

Proceedings of 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, Vol.2, p.1357 - 1374, 2016/05

With respect to the long-term storage of the zeolite-containing spent Cs adsorption vessels used at the Fukushima Daiichi Nuclear Power Station, the corrosion of the vessel material is one of the most important issues. In this study, we performed electrochemical tests on stainless steel specimens in zeolite-containing artificial seawater under gamma-ray irradiation. The spontaneous potential ESP and critical pitting potential VC of the type 316L steel in systems in contact with various zeolites were measured in order to evaluate the corrosion resistance of the steel. In addition, the water sample was analyzed after being irradiated, in order to determine the concentrations of various dissolved oxidants such as oxygen and hydrogen peroxide, which can accelerate the corrosion process. The steady-state rest potential increased with an increase in the dose rate; however, the increase was suppressed in contact with the zeolites. The VC value of the steel when in contact with the zeolites was slightly smaller than the VC value in bulk water; however, the choice of the zeolite used as herschelite, IE96 and IE911 hardly affect the VC value. The concentration of H$$_{2}$$O$$_{2}$$ in the bulk water under irradiation also increased with the increase in the dose rate. This increase was suppressed in the systems in contact with the zeolites, owing to the decomposition of the H$$_{2}$$O$$_{2}$$ by the zeolites. A clear relationship was observed between ESP and the H$$_{2}$$O$$_{2}$$ concentration. As contact with the zeolites caused the increase in ESP under irradiation to be suppressed, it can be concluded that the presence of zeolites in the spent Cs adsorption vessels can reduce the probability of the localized corrosion of the stainless steel in the vessels.

Journal Articles

Vacuum chromatography of Tl on SiO$$_{2}$$ at the single-atom level

Steinegger, P.*; Asai, Masato; Dressler, R.*; Eichler, R.*; Kaneya, Yusuke*; Mitsukai, Akina*; Nagame, Yuichiro; Piguet, D.*; Sato, Tetsuya; Sch$"a$del, M.; et al.

Journal of Physical Chemistry C, 120(13), p.7122 - 7132, 2016/04

 Times Cited Count:18 Percentile:63.22(Chemistry, Physical)

A new experimental method "vacuum chromatography" has been developed to measure adsorption enthalpy of superheavy elements, and its feasibility has been examined using short-lived thallium isotopes. The short-lived thallium isotopes were produced at the JAEA tandem accelerator. The thallium ion beam prepared with an on-line isotope separator which ionized and mass-separated the thallium isotopes was injected into an isothermal vacuum chromatography apparatus. A temperature-dependent adsorption property of thallium atom on SiO$$_{2}$$ surface were measured. The adsorption enthalpy of thallium was determined to be 158 kJ/mol. The thallium is a homolog of element 113. Thus, the vacuum chromatography developed in this study enables us to perform chemical experiments for short-lived superheavy elements with half-lives of a order of one second.

Journal Articles

Adsorption kinetics, isotherms, and thermodynamic studies for the adsorption of Pb$$^{2+}$$ and Hg$$^{2+}$$ metal ions from aqueous medium using Ti(IV) iodovanadate cation exchanger

Naushad, M.*; Alothman, Z. A.*; Awual, M. R.; Alam, M. M.*; Eldesoky, G. E.*

Ionics, 21(8), p.2237 - 2245, 2015/08

 Times Cited Count:208 Percentile:99.62(Chemistry, Physical)

Journal Articles

Degradation of 2-chlorophenol by $$gamma$$-ray irradiation in zeolite/water mixtures

Kumagai, Yuta

Hoshasen Kagaku (Internet), (99), p.53 - 56, 2015/04

Radiation-induced degradation of 2-chlorophenol (2-ClPh) in zeolite/water mixtures was studied in order to consider a possibility of adsorption on zeolites to improve efficiencies of irradiation treatments of water contaminated by organic compounds. The degradation of 2-ClPh by $$gamma$$-ray irradiation was investigated as a model compound. The degradation was evaluated by chloride ion (Cl$$^{-}$$) production. A high concentration of Cl$$^{-}$$ was observed after the irradiation of a mixture with a mordenite-type zeolite (NaMOR), whereas A-type and X-type zeolites showed no significant effect. Therefore, for the mixture with NaMOR, effects of pH of the solution and of the 2-ClPh concentration were examined. At pH 5.7, the excess production of Cl$$^{-}$$ was induced by the addition of NaMOR. Concurrently, adsorption of 2-ClPh on NaMOR was observed. When the mixture contained a higher concentration of 2-ClPh at pH 5.7, the Cl$$^{-}$$ production increased. The adsorption of 2-ClPh also increased with increasing concentration. The results suggest that organics adsorbed on zeolites are decomposed by irradiation effectively at high adsorption concentrations.

Journal Articles

Adsorption properties of styrenesulfonate-grafted fibrous metal adsorbent

Ueki, Yuji; Saiki, Seiichi; Seko, Noriaki

Nihon Ion Kokan Gakkai-Shi, 25(4), p.99 - 104, 2014/11

Journal Articles

Cesium-adsorption behavior of weathered biotite from Fukushima Prefecture depends on the degree of vermiculitization

Yamada, Hirohisa*; Yokoyama, Shingo*; Watanabe, Yujiro*; Suzuki, Masaya*; Suzuki, Shinichi; Hatta, Tamao*

Nihon Ion Kokan Gakkai-Shi, 25(4), p.207 - 211, 2014/11

JAEA Reports

Separation of $$^{14}$$C from irradiated graphite materials, 1; Oxidation behaviors and the changes in pore structure of Q1 and IG-110 graphite due to the air reaction (Joint research)

Fujii, Kimio

JAERI-Tech 2005-048, 108 Pages, 2005/09

JAERI-Tech-2005-048.pdf:25.05MB

The graphite-moderated power reactor was shut down in 1998 and its decommissioning program is being planned. Various graphites are used in the core of magnox-type reactors and HTTR as core-support structural materials and moderating materials of fast neutrons. For the nuclear graphite disposal, it is necessary to determine especially the treatment of long-lived nuclides, such as $$^{14}$$C which are generated in the graphite components during reactor operation. As a research, which solves the problem of the $$^{14}$$C concentration, the cooperative research is concluded between JAERI and Japan Nuclear Power Corp. in 1999, and the research for the basic data acquisition has been advanced up to the present. To find the optimum conditions for $$^{14}$$C reduction, basic data on oxidation reaction and the structure of graphite materials are indispensable. In the present experiment, we measure the air oxidation characteristics in the temperature range 450$$sim$$800$$^{circ}$$C in Quality1 graphite and IG-110 graphite. Changes in pore diameter and pore size distribution due to air oxidation are discussed.

JAEA Reports

Research and development on partitioning in JAERI; Review of the research activities until the development of 4-group partitioning process

Morita, Yasuji; Kubota, Masumitsu*

JAERI-Review 2005-041, 35 Pages, 2005/09

JAERI-Review-2005-041.pdf:2.24MB

Research and development on Partitioning in JAERI are reviewed in the present report from the beginning to the development of the 4-Group Partitioning Process and its test with real high-level liquid waste (HLLW). In the 3-Group Partitioning Process established in around 1980, elements in HLLW are separated into 3 groups of transuranium element group, Sr-Cs group and the other element group. The 4-Group Partitioning Process subsequently developed contains the separation of Tc-platinum group metals additionally. The process was tested to demonstrate its performance with real concentrated HLLW. Until then, various separation methods for various elements were studied and selection and optimization of the separation methods were carried out to establish the process. Review of the experience, findings and results is very important and valuable for future study on partitioning. The present report is prepared from this point of view.

Journal Articles

Oxidation reaction kinetics on Ti(0001) surface studied by real-time photoelectron spectroscopy

Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden

Shokubai, 47(5), p.352 - 357, 2005/08

Oxidation reactions of Ti(0001) surfaces were monitored by real-time photoelectron spectroscopy with high brilliant synchrotron radiation and He-I resonance line. An oxygen adsorption model and ultra-thin oxide layers formation processes were reviewed on the basis of time evolutions of the adsorbed oxygen amount, oxidation states, electronic states and the work function, which were obtained from photoelectron spectra for Ti 2p and O 1s core levels as well as the valence band.

Journal Articles

Adsorption efficiency of a new adsorbent towards uranium and vanadium ions at low concentrations

Kavakli, P. A.*; Seko, Noriaki; Tamada, Masao; G$"u$ven, O.*

Separation Science and Technology, 39(7), p.1631 - 1643, 2005/00

 Times Cited Count:52 Percentile:84.2(Chemistry, Multidisciplinary)

A new type of fibrous adsorbent with excess amidoxime groups was synthesized by radiation-induced graft polymerization. Glycidyl methacrylate (GMA) was first radiation-grafted on polyethylene-coated polypropylene nonwoven fabrics and chemically modified with 3,30-iminodipropionitrile [NH (-CH$$_{2}$$-CH$$_{2}$$-CN)$$_{2}$$] (IDPN), which was further reacted with hydroxylamine to obtain graft chains containing two amidoxime groups per graft repeating units. The adsorption properties of this new adsorbent for uranium (U), vanadium (V), lead (Pb), copper (Cu), and cobalt (Co) ions at low concentrations (3.3-1000 ppb).

Journal Articles

Interactions between anionic complex species of actinides and negatively charged mineral surfaces

Yamaguchi, Tetsuji; Nakayama, Shinichi; Yoshida, Takahiro

Radiochimica Acta, 92(9-11), p.677 - 682, 2004/12

 Times Cited Count:5 Percentile:36.97(Chemistry, Inorganic & Nuclear)

Adsorption of actinides onto negatively charged mineral surfaces was investigated under conditions that actinides were predominantly present as anionic complex species: Th(CO$$_{3}$$)$$_{5}$$$$^{6-}$$, Am(CO$$_{3}$$)$$_{3}$$$$^{3-}$$, Np(CO$$_{3}$$)$$_{2}$$(OH)$$_{2}$$$$^{2-}$$, UO$$_{2}$$(OH)$$_{4}$$$$^{2-}$$, NpO$$_{2}$$(OH)$$_{2}$$$$^{-}$$, Sn(OH)$$_{5}$$$$^{-}$$ and Pb(OH)$$_{3}$$$$^{-}$$. These solutions were left to stand for 2 days to confirm these elements stable in dissolved state, and then contacted with minerals, $$gamma$$-Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$ (AEROSIL, specific surface area: 10$$^{5}$$ m$$^{2}$$ kg$$^{-1}$$). After desired contact time for 2 days or more, the solutions were ultra-filtered through 10$$^{4}$$-molecular-weight cutoff Millipore filters and the concentrations of the elements in the filtrates were determined. The sorption experiments were performed at room temperature (25$$^{circ}$$C) under Ar. Distribution coefficients decreased with the increasing pH and with increasing carbonate concentrations. The monotonous decrease in the distribution coefficients in the investigated pH range suggests that the electrostatic repulsion was a dominant interaction between anionic complex species of actinides and negatively charged mineral surfaces.

Journal Articles

Rapid removal of arsenic(V) by zirconium(IV) loaded phosphoric chelate adsorbent synthesized by radiation induced graft polymerization

Seko, Noriaki; Basuki, F.*; Tamada, Masao; Yoshii, Fumio

Reactive and Functional Polymers, 59(3), p.235 - 241, 2004/07

 Times Cited Count:52 Percentile:83.84(Chemistry, Applied)

Fibrous arsenic(As) adsorbent was synthesized by loading zirconium(Zr) on fibrous phosphoric adsorbent which was directly synthesized by radiation-induced grafting of 2-hydroxyethyl methacrylate phosphoric acid on polyethylene-coated polypropylene nonwoven fabric. Zirconium reacted with phosphoric acid grafted in the polyethylene layer. Zirconium density of the resulting adsorbent was 4.1 mmol/g. The breakthrough curve of As(V) adsorption was independent of the flow rate up to 1300 h$$^{-1}$$ in space velocity. The total capacity of As(V) was 2.0 mmol/ g-adsorbent at pH of 2. The adsorbed Zr(IV) could be evaluated by 0.4 M sodium hydroxide solution because no Zr(IV) could be found in the eluted solution. Anions of chloride and nitrate interfered the breakthrough capacity.

Journal Articles

Tuning of dissociative-adsorption processes on Cu{1 0 0} by controlling the kinetic energy of the impinging O$$_{2}$$ molecule

Okada, Michio*; Moritani, Kosuke; Yoshigoe, Akitaka; Teraoka, Yuden; Nakanishi, Hiroshi*; Di$~n$o, W. A.*; Kasai, Hideaki*; Kasai, Toshio*

Chemical Physics, 301(2-3), p.315 - 320, 2004/06

 Times Cited Count:14 Percentile:43.58(Chemistry, Physical)

O$$_{2}$$ molecules adsorb dissociatively on Cu{1 0 0} surfaces to form the oxygen-saturated surface with the coverage of 0.5 ML. It has been found that the oxidation has proceeded more than 0.5 ML by using 2.3-eV-O$$_{2}$$ molecular beams. The kinetics of the adsorption reaction was the first order. This reveals that the collision-induced adsorption results in the adsorption of only one oxygen atom. On the other hand, the reaction kinetics showed the second order in the case of 0.6-eV-O$$_{2}$$ incidence. This implies that tentative molecular adsorption takes place in such low collision energy case.

Journal Articles

Aquaculture of uranium in seawater by a fabric-adsorbent submerged system

Seko, Noriaki; Katakai, Akio; Hasegawa, Shin; Tamada, Masao; Kasai, Noboru; Takeda, Hayato*; Sugo, Takanobu; Saito, Kyoichi*

Nuclear Technology, 144(2), p.274 - 278, 2003/11

 Times Cited Count:103 Percentile:98.43(Nuclear Science & Technology)

The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg-U/m$$^{3}$$ in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific non-woven fabric was used as the adsorbent packed in an adsorption cage. We submerged adsorption cages, 16 m$$^{2}$$ in cross-sectional area and 16 cm in height, in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The cage consisted of stacks of 52,000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the non-woven fabric was more than one kg in terms of yellow cake during a total submersion time of 240 days in the ocean.

Journal Articles

Actively controlled oxidation of Cu{001} with hyperthermal O$$_{2}$$ molecular beam

Okada, Michio*; Moritani, Kosuke; Goto, Seishiro*; Kasai, Toshio*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Chemical Physics, 119(14), p.6994 - 6997, 2003/10

 Times Cited Count:41 Percentile:79.17(Chemistry, Physical)

The oxidation of Cu(001) with hyperthermal O$$_{2}$$ molecular beams was investigated using X-ray photoemission spectroscopy in conjunction with a synchrotron light source. The efficiency of oxidation is higher than that with ambient thermal O$$_{2}$$. Further oxidation under oxygen coverage larger than 0.5 ML occurs rather inefficiently even for the 2.3 eV beam irradiation. We found such slow oxidation of Cu corresponding to the initial stage of the Cu$$_{2}$$O formation can be interpreted in terms of a collision-induced-adsorption mechanism. The kinetics of the dissociative adsorption is well described using the first order kinetics in a simple Langmuir-type adsorption model.

65 (Records 1-20 displayed on this page)