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Journal Articles

Effect on $$^{99}$$Mo-adsorption/$$^{99m}$$Tc-elution properties of alumina with different surface structures

Fujita, Yoshitaka; Seki, Misaki; Sano, Tadafumi*; Fujihara, Yasuyuki*; Kitagawa, Tomoya*; Matsukura, Minoru*; Hori, Junichi*; Suzuki, Tatsuya*; Tsuchiya, Kunihiko

Journal of Radioanalytical and Nuclear Chemistry, 327(3), p.1355 - 1363, 2021/03

 Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)

We prepared three types of Al$$_{2}$$O$$_{3}$$ with different surface structures and investigated $$^{99}$$Mo-adsorption/$$^{99m}$$Tc-elution properties using [$$^{99}$$Mo]MoO$$_{3}$$ that was irradiated in the Kyoto University Research Reactor. Al$$_{2}$$O$$_{3}$$ adsorbed [$$^{99}$$Mo]molybdate ions in solutions at different pH; the lower was the pH, the higher was the Mo-adsorption capacity of Al$$_{2}$$O$$_{3}$$. The $$^{99m}$$Tc-elution properties of molybdate ion adsorbed Al$$_{2}$$O$$_{3}$$ were elucidated by flowing saline. Consequently, it was suggested that $$^{99}$$Mo-adsorption/desorption properties are affected by the specific surface of Al$$_{2}$$O$$_{3}$$ and $$^{99m}$$Tc-elution properties are affected by the crystal structure of Al$$_{2}$$O$$_{3}$$.

Journal Articles

Precious metal separations

Narita, Hirokazu*; Kasuya, Ryo*; Suzuki, Tomoya*; Motokawa, Ryuhei; Tanaka, Mikiya*

Encyclopedia of Inorganic and Bioinorganic Chemistry (Internet), 28 Pages, 2020/12

Journal Articles

Atomistic simulations for the effects of stacking fault energy on defect formations by displacement cascades in FCC metals under Poisson's deformation

Hayakawa, Sho*; Okita, Taira*; Itakura, Mitsuhiro; Kawabata, Tomoya*; Suzuki, Katsuyuki*

Journal of Materials Science, 54(16), p.11096 - 11110, 2019/08

 Times Cited Count:3 Percentile:28.74(Materials Science, Multidisciplinary)

Journal Articles

Effects of stacking fault energies on formation of irradiation-induced defects at various temperatures in face-centred cubic metals

Nakanishi, Daiki*; Kawabata, Tomoya*; Doihara, Kohei*; Okita, Taira*; Itakura, Mitsuhiro; Suzuki, Katsuyuki*

Philosophical Magazine, 98(33), p.3034 - 3047, 2018/09

 Times Cited Count:4 Percentile:36.14(Materials Science, Multidisciplinary)

By using the six sets of interatomic potentials for face-centredcubic metals that differ in the stacking fault energy (SFE) while most of the other material parameters are kept almost identical, we conducted molecular dynamics simulations to evaluate the effects of SFE on the defect formation process through collision cascades. The ratio of glissile SIA clusters tends to decrease with increasing SFE. This is because perfect loops, the edges of which split into two partial dislocations with stacking fault structures between them in most cases, prefer to form at lower SFEs. The enhanced formation of glissile SIA clusters at lower SFEs can also be observed even at increased temperature.

Journal Articles

Speciation of ruthenium(III) chloro complexes in hydrochloric acid solutions and their extraction characteristics with an amide-containing amine compound

Suzuki, Tomoya*; Ogata, Takeshi*; Tanaka, Mikiya*; Kobayashi, Toru; Shiwaku, Hideaki; Yaita, Tsuyoshi; Narita, Hirokazu*

Metals, 8(7), p.558_1 - 558_10, 2018/07

AA2018-0670.pdf:2.11MB

 Times Cited Count:9 Percentile:63.65(Materials Science, Multidisciplinary)

The refining of platinum group metals is based mainly on solvent extraction methods, whereas Ru is selectively recovered by distillation as RuO$$_4$$. Replacement of distillation byextraction is expected to simplify the purification process. To develop an effective extraction system for Ru, we analyzed the Ru species in HCl with UV-Vis and EXAFS spectroscopies, and we examined the properties of Ru extracted with N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide) amine (EHBAA). EXAFS and UV-Vis spectra of Ru in HCl solutions revealed that the predominant Ru species in 0.5-10 M HCl solutions changed from [RuCl$$_4$$(H$$_2$$O)$$_2$$]$$^-$$ to [RuCl$$_6$$]$$^3$$$$^-$$ with the HCl concentration. The extraction percentages of Ru in the EHBAA system increased with increasing HCl concentration, reached 80% at [HCl] = 5 M, and decreased athigher HCl concentrations. EXAFS analysis of the extracted complex indicated that the Ru$$^3$$$$^+$$ had 5 Cl$$^-$$ and 1 H$$_2$$O in its inner coordination sphere. The similarity of the dependence on HCl concentrations of the extraction in the EHBAA system and the distribution profile of [RuCl$$_5$$(H$$_2$$O)]$$^2$$$$^-$$ on [RuCl$$_n$$(H$$_2$$O)$$_6$$$$_-$$$$_n$$]$$^3$$$$^-$$$$^n$$ suggested that the EHBAA extracted the pentachlorido species.

Journal Articles

Molybdenum adsorption and desorption properties of alumina with different surface structures for $$^{99}$$Mo/$$^{99m}$$Tc generators

Suzuki, Yoshitaka; Kitagawa, Tomoya*; Namekawa, Yoji*; Matsukura, Minoru*; Nishikata, Kaori; Mimura, Hitoshi*; Tsuchiya, Kunihiko

Transactions of the Materials Research Society of Japan, 43(2), p.75 - 80, 2018/04

no abstracts in English

Journal Articles

Comparison of the extractabilities of tetrachloro- and tetrabromopalladate(II) ions with a thiodiglycolamide compound

Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi

Analytical Sciences, 33(11), p.1305 - 1309, 2017/11

 Times Cited Count:6 Percentile:33.73(Chemistry, Analytical)

Journal Articles

Recent research in solvent extraction of platinum group metals

Narita, Hirokazu*; Suzuki, Tomoya*; Motokawa, Ryuhei

Nihon Kinzoku Gakkai-Shi, 81(4), p.157 - 167, 2017/04

 Times Cited Count:9 Percentile:55.7(Metallurgy & Metallurgical Engineering)

Journal Articles

Separation of Ru(III), Rh(III) and Pd(II) from nitric acid solutions using ion-exchange resins bearing carboxylic betaine

Suzuki, Tomoya; Morita, Keisuke; Sasaki, Yuji; Matsumura, Tatsuro

Separation Science and Technology, 51(17), p.2815 - 2822, 2016/09

 Times Cited Count:5 Percentile:26.43(Chemistry, Multidisciplinary)

To understand the adsorption properties of styrene-divinylbenzene copolymer functionalized with ${it N,N,N}$-trimethylglycine, AMP03, the adsorption behaviors for platinoid ions (Ru(III), Rh(III), and Pd(II)) were examined. Furthermore, we performed adsorption experiments using sample solutions with adding triethylamine, thiourea, and ${it N,N,N}$-trimethylglycine. Based on the adsorption data obtained in this study, we performed chromatographic experiments. The results indicated that all platinoid ions in the feed solution completely adsorbed on AMP03, and almost 80% of the adsorbed platinoid ions were recovered. These results show that AMP03 has the potential to recover Ru(III), Rh(III), and Pd(II) from high-level liquid waste.

Journal Articles

Recovery of Rhodium(III) from nitric acid solutions using adsorbent functionalized with ${it N,N,N}$-trimethylglycine

Suzuki, Tomoya; Morita, Keisuke; Sasaki, Yuji; Matsumura, Tatsuro

Bulletin of the Chemical Society of Japan, 89(5), p.608 - 616, 2016/05

 Times Cited Count:3 Percentile:16.13(Chemistry, Multidisciplinary)

In a previous study, we found that AMP03 adsorbs Rh(III) from the HNO$$_{3}$$ solution with pH = 1.7 - 2.2. In this study, to understand the Rh(III) adsorption properties of AMP03 and clarify conditions for efficient recovery, we investigated the adsorption behaviors of Rh(III) from the HNO$$_{3}$$ solution. As a result, it was found that Rh(III) is effectively adsorbed from aqueous solution containing low H$$^{+}$$ and high NO$$_{3}$$$$^{-}$$ concentration. Considering the adsorption mechanism of Rh(III), we found that Rh$$^{3+}$$ in aqueous solution is adsorbed with two betaine groups in AMP03 and three NO$$_{3}$$$$^{-}$$.

Journal Articles

Silver extraction by $$N,N,N',N'$$-tetraoctyl-thiodiglycolamide

Sasaki, Yuji; Suzuki, Tomoya; Morita, Keisuke; Yoshizuka, Kazuharu*

Hydrometallurgy, 159, p.107 - 109, 2016/01

 Times Cited Count:5 Percentile:35.63(Metallurgy & Metallurgical Engineering)

The novel tridentate extractant including soft donor has developed and examined. The extractant, tetraoctyl-thiodiglycolamide (S-DGA), is analogous structure to tetraoctyl-diglycolamide (TODGA), but with sulfur donor instead of ether oxygen of TODGA. S-DGA has unique property to extract silver from acidic solutions to n-dodecane with relatively high D values. We investigated the extraction behavior of Ag in various acids, HNO$$_{3}$$, H$$_{2}$$SO$$_{4}$$, and HClO$$_{4}$$.

Journal Articles

Investigation of single-cycle separation process based on forward and backward extractions of actinides and fission products

Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Morita, Keisuke; Suzuki, Tomoya

Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(3), p.202 - 212, 2015/09

We have been developing the new partitioning method of high-level radioactive waste by single-cycle extraction process. This process is composed of extraction of actinides (An) and fission products (FP, e.g., Pd, Ru, Mo and Tc), and mutual separation by back-extraction. The extractant employed in this process is required to extract soft, hard acid metals and oxonium anions simultaneously. The NTAamide (hexaoctyl-nitrilotriacetamide) is one of the candidate extractants. After extraction of An and FP, the mutual separation by back-extraction should be set up. Pd and Ru extracted by NTAamide can be back-extracted by complexing agents such as thiourea, systeine, diethylenetriamine, and trisaminoethylamine, and the back-extraction of Mo can be performed by methylimino-diethylacetamide (MIDEA), NTAamide(C2) and iminodimethylphosphoric acid, and Re can be done by aqueous phase with high pH.

Journal Articles

Concept for the single cycle process based on mutual separation by reverse extraction of actinides and fission products

Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Morita, Keisuke; Suzuki, Tomoya

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1653 - 1656, 2015/09

The concept for the new partitioning method of high-level radioactive waste (HLW) by single-cycle extraction process has been investigated. This process is based on extraction of actinides (An) and fission products (FP), and mutual separation by reverse extraction. Solo extractant and several stripping reagents will be utilized in this process. The extractant employed in this process is required to extract soft (platinum metals), hard acid metals(An), and oxonium anions (Mo, Tc) simultaneously. NTAamide is one of the candidate extractants. After extraction of An and FP by NTAamide(C8), the mutual separation among these metals by reverse extraction will be followed using the suitable water-miscible reagents. The extraction of An and FP, and the masking effect by some water-miscible reagents has been studied.

Journal Articles

A Study on adsorption properties of ion-exchange resins bearing ${it N,N,N}$-trimethylglycine to Ru(III), Rh(III) and Pd(II) for developing separation techniques from high-level liquid waste

Suzuki, Tomoya; Shimazaki, Shoma*; Morita, Keisuke; Sasaki, Yuji; Ozawa, Masaki*; Matsumura, Tatsuro

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1539 - 1543, 2015/09

To understand the adsorption behaviors of ion-exchange resin bearing ${it N,N,N}$-trimethylglycine groups (AMP03), adsorption experiments using HNO$$_{3}$$ solutions containing Ru(III), Rh(III), and Pd(II) have been performed. AMP03 strongly adsorbed Pd(II), and Ru(III) and Rh(III) were moderately adsorbed. To control the adsorption abilities of AMP03 for the Ru(III), Rh(III) and Pd(II), adsorption experiments using sample solutions with added thiourea (TU), triethylamine (TEA), and betaine anhydrous were performed. The adsorption abilities for Ru(III) and Rh(III) greatly increased with the addition of TEA, whereas the ability to adsorb Pd(II) was not significantly affected. The addition of TU or betaine anhydrous remarkably decreased the adsorption ability for Pd(II), and contrastingly slight changes in the abilities to adsorb Ru and Rh were also observed. These results show that AMP03 has a significant potential for separation of platinoid elements from HNO$$_{3}$$ solution.

Journal Articles

Correlation between intermolecular hydrogen bonds and melting points of uranyl nitrate complexes with cyclic urea derivatives

Suzuki, Tomoya; Takao, Koichiro*; Kawasaki, Takeshi*; Harada, Masayuki*; Nogami, Masanobu*; Ikeda, Yasuhisa*

Polyhedron, 96, p.102 - 106, 2015/08

 Times Cited Count:5 Percentile:47(Chemistry, Inorganic & Nuclear)

We have determined crystal structures of UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(${bf 0a}$)$$_{2}$$ (${bf 0a}$: 2-imidazolidone), UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(${bf 0b}$)$$_{2}$$ (${bf 0b}$: tetrahydro-2-pyrimidone) and UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(${bf 1a}$)$$_{2}$$ (${bf 1a}$: 1-methyl-2-imidazolidone) by using single crystal X-ray analysis, and examined correlations between melting points (mps) and intermolecular hydrogen bonds (HBs) of UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(CU)$$_{2}$$ (CU: cyclic urea derivatives) and UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(NRP)$$_{2}$$ (NRP: pyrrolidone derivative).

Journal Articles

Development of a widely usable amino acid tracer; $$^{76}$$Br-$$alpha$$-methyl-phenylalanine for tumor PET imaging

Hanaoka, Hirofumi*; Ohshima, Yasuhiro; Suzuki, Yurika*; Yamaguchi, Aiko*; Watanabe, Shigeki; Uehara, Tomoya*; Nagamori, Shushi*; Kanai, Yoshikatsu*; Ishioka, Noriko; Tsushima, Yoshito*; et al.

Journal of Nuclear Medicine, 56(5), p.791 - 797, 2015/05

 Times Cited Count:15 Percentile:65.72(Radiology, Nuclear Medicine & Medical Imaging)

Journal Articles

Studies on the extraction of soft acid metal species using MIDOA and analogous compounds

Sasaki, Yuji; Saeki, Morihisa; Sugo, Yumi; Ikeda, Yasuhisa*; Kawasaki, Takeshi*; Suzuki, Tomoya*; Ohashi, Akira*

Solvent Extraction Research and Development, Japan, 22(1), p.37 - 45, 2015/05

 Times Cited Count:9 Percentile:37.92(Chemistry, Multidisciplinary)

An extractant, methylimino-bis-${it N,N'}$-dioctylacetamide (MIDOA), was used for the extraction of soft acid metals. It was found that MIDOA can extract not only Cr(VI), Mo(VI), W(VI), Tc(VII) and Re(VII), whose metals can form the oxonium anions due to their high oxidation states, but also other metal cations, like Nb(V), Ta(V) and Pd(II). Analogous compounds, imino-bis-${it N,N'}$-dioctylacetamide (IDOA) and methylimino-bis-${it N,N'}$-di-2-ethylhexylacetamide (MIDEHA), are synthesized and compared for their extractability. It is clear that these extractants have almost same or lower $$D$$ values than those for MIDOA. In order to examine the effect on extractability with different donor atoms, TODGA (${it N,N,N',N'}$-tetraoctyl-diglycolamide) and TDGA (${it N,N,N',N'}$-tetraoctyl-tyiodiglycolamide) having oxygen and sulfur donor are employed. The comparison of their extractabilities suggests that the trend of Pd and Re extraction is N $$>$$ S $$>$$ O and N $$>$$ O $$>$$ S, respectively.

Journal Articles

Efficient adsorption of Rh(III) from HNO$$_{3}$$ solution on ion-exchange resin bearing ${it N,N,N}$-trimethylglycine by adding N donor ligands and desorption using thiourea

Suzuki, Tomoya; Morita, Keisuke; Sasaki, Yuji

Chemistry Letters, 44(2), p.152 - 153, 2015/02

 Times Cited Count:2 Percentile:10.24(Chemistry, Multidisciplinary)

To recover Rh(III) from HNO$$_{3}$$ solution, adsorption experiments have been performed using an ion-exchange resin bearing an ${it N,N,N}$-trimethylglycine group (AMP03). AMP03 was found to exhibit relatively high adsorption ability for Rh(III) for [HNO$$_{3}$$]$$_{rm surp}$$ $$<$$ 0.02 M ([HNO$$_{3}$$]$$_{rm surp}$$ denotes HNO$$_{3}$$ concentration in the supernatant), and the ${it K$_{d}$}$ values increase significantly with the addition of triethylamine or tris(2-aminoethyl)amine to 0.12 M HNO$$_{3}$$ solutions. In contrast, the addition of thiourea leads to a decrease in the ${it K$_{d}$}$ values; i.e., a masking effect on Rh(III) was observed. These results show that AMP03 has a significant potential for effectively recovering Rh from HNO$$_{3}$$ solution.

Journal Articles

Complexing agents for oxonium anions of Mo and Re and their masking effects on extraction using N-donor extractants

Sasaki, Yuji; Suzuki, Tomoya; Morita, Keisuke; Tsubata, Yasuhiro

Chemistry Letters, 43(10), p.1538 - 1539, 2014/10

 Times Cited Count:4 Percentile:19.55(Chemistry, Multidisciplinary)

Several complexing agents including soft donor in their structures are examined for the masking effects of Mo and Re through solvent extraction. The available extractants are hexaoctyl-nitrilotriacetamide (NTAamide) and methyliminodioctylacetamide (MIDOA), whose extractants have high D(Mo, Re). It is clear that Mo and Re in HNO$$_{3}$$ dissolving N-donor ligands, ethylenediamine, diethylenetriamine, and 1,3-diaminopropane, can be suppressed for extraction into organic phase. The ligands including sulfur donor, e.g., thiourea, are also tested, however, less masking effect can be seen.

Journal Articles

Effect of the central frames and substituents attached to N atoms on extraction ability of podand-type extractants

Sasaki, Yuji; Kitatsuji, Yoshihiro; Sugo, Yumi; Tsubata, Yasuhiro; Suzuki, Tomoya; Kimura, Takaumi; Morita, Yasuji

Proceedings of 20th International Solvent Extraction Conference (ISEC 2014), p.431 - 435, 2014/09

The eight amide extractants including podand-types, which introduce oxygen, nitrogen and sulfur donor atoms in their central frame, are synthesized and their D values for actinide extraction are compared. The central frame affect greatly on their extractability and it is clear that diglycolamide (DGA) has the highest extractability among extractants used here. In addition, DGA having the different length of alkyl chain or phenyl groups attached to amidic N atoms are obtained and the effect of these substituents is studied. Due to the steric hindrance or hydrogen bond, DGA with long and branched alkyl chains, phenyl group, and proton give relatively low D values.

51 (Records 1-20 displayed on this page)