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Journal Articles

Effective extraction of Pt(IV) as [PtCl$$_{6}$$]$$^{2-}$$ from hydrochloric acid using a simple urea extractant

Ueda, Yuki; Morisada, Shintaro*; Kawakita, Hidetaka*; Wenzel, M.*; Weigand, J. J.*; Oto, Keisuke*

Separation and Purification Technology, 277, p.119456_1 - 119456_8, 2021/12

no abstracts in English

Journal Articles

Selective extraction of platinum(IV) from the simulated secondary resources using simple secondary amide and urea extractants

Ueda, Yuki; Morisada, Shintaro*; Kawakita, Hidetaka*; Oto, Keisuke*

Separations (Internet), 8(9), p.139_1 - 139_15, 2021/09

no abstracts in English

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n, $$gamma$$) method, 3

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Daigo, Fumihisa; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.

KURNS Progress Report 2020, P. 136, 2021/08

no abstracts in English

Journal Articles

Stoichiometry of lanthanide-phosphate complexes at the water surface studied using vibrational sum frequency generation spectroscopy and DFT calculations

Kusaka, Ryoji; Watanabe, Masayuki

Journal of Physical Chemistry B, 125(24), p.6727 - 6731, 2021/06

 Times Cited Count:0 Percentile:0(Chemistry, Physical)

Journal Articles

A Fluorous phosphate for the effective extraction of Ln$$^{III}$$ from nitrate media; Comparison with a conventional organic phosphate

Ueda, Yuki; Kikuchi, Kei*; Tokunaga, Kohei; Sugita, Tsuyoshi; Aoyagi, Noboru; Tanaka, Kazuya; Okamura, Hiroyuki

Solvent Extraction and Ion Exchange, 39(5-6), p.491 - 511, 2021/00

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

no abstracts in English

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

Journal Articles

Development of lanthanide and actinide studies toward interface chemistry using vibrational sum frequency generation spectroscopy

Kusaka, Ryoji

Hosha Kagaku, (41), p.31 - 33, 2020/03

This commentary article introduced researches involved in encouragement award 2019 of the Japan Society of Nuclear and Radiochemical Sciences. Vibrational sum frequency generation (VSFG) spectroscopy and interfacial studies of solvent extraction of lanthanides and actinides using VSFG spectroscopy were described.

Journal Articles

Effects of diluents on the separation of minor actinides from lanthanides with tetradodecyl-1,10-phenanthroline-2,9-diamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Suzuki, Hideya*; Nakase, Masahiko*; Ito, Sayumi*; Inaba, Yusuke*; Matsumura, Tatsuro; Takeshita, Kenji*

Analytical Sciences, 36(2), p.241 - 246, 2020/02

 Times Cited Count:3 Percentile:45.02(Chemistry, Analytical)

To investigate the effective separation of actinides (Ans) from lanthanides (Lns), single-stage batch extraction experiments were performed with a novel extractant, tetradodecyl-1,10-phenanthroline-2,9-diamide (TDdPTDA) with various diluents such as 3-nitrobenzotrifluoride (F-3), nitrobenzene, and ${it n}$-dodecane for Am, Cm, and Lns. The extraction kinetics with TDdPTDA was rapid enough to perform the actual extraction flow sheet. The slopes of the distribution ratio versus TDdPTDA concentration and the distribution ratio versus nitric acid concentration were similar for F-3 and nitrobenzene systems but different from ${it n}$-dodecane system. These differences were attributed to the characteristics of the diluents. This study reveals high distribution ratios of Am (${it D}$ $$_{Am}$$) and Cm (${it D}$ $$_{Cm}$$) for TDdPTDA, with the high separation factors (${it SF}$s) of Am from Lns enough for their separation.

Journal Articles

Development of select process for minor actinides partitioning from high level waste

Matsumura, Tatsuro

Kino Zairyo, 40(1), p.60 - 71, 2020/01

no abstracts in English

Journal Articles

Minor actinides separation by ${it N,N,N',N',N'',N''}$-hexaoctyl nitrilotriacetamide (HONTA) using mixer-settler extractors in a hot cell

Ban, Yasutoshi; Suzuki, Hideya*; Hotoku, Shinobu; Tsutsui, Nao; Tsubata, Yasuhiro; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 37(7), p.489 - 499, 2019/11

 Times Cited Count:5 Percentile:45(Chemistry, Multidisciplinary)

A continuous counter-current experiment to separate minor actinides (MAs: Am and Cm) was performed with ${it N,N,N',N',N'',N''}$-hexaochyl nitrilotriacetamide (HONTA) as an extractant. Nitric acid of 0.08 M (mol/dm$$^{3}$$) containing MAs and rare earths (REs) recovered from high-level waste was used as the Feed, and the experiment was conducted for 14 h. The ratios of Am and Cm recovered into the MA fraction measured 94.9% and 78.9%, respectively. HONTA hardly extracted Y, La, and Eu in the Feed (99.9% for Y, 99.9% for La, and 96.7% for Eu), most of which were distributed to the RE fraction. A portion of Nd was extracted by HONTA, and consequently the ratio of Nd in the RE fraction was 83.5%. The concentrations of MAs and some REs in each stage were calculated using a simulation code, and the results are consistent with the experimental values. This code indicates that the ratios of MAs in the MA fraction and REs in the RE fraction could be $$geq$$99% by optimizing separation conditions.

Journal Articles

Zr separation from high-level liquid waste with a novel hydroxyacetoamide type extractant

Morita, Keisuke; Suzuki, Hideya; Matsumura, Tatsuro; Takahashi, Yuya*; Omori, Takashi*; Kaneko, Masaaki*; Asano, Kazuhito*

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.464 - 468, 2019/09

High level liquid waste (HLLW) contains several radionuclides with half-lives longer than 10$$^{6}$$ year. For reduce environmental burden of waste disposal, minor actinoids and long-lived fission products will to be partitioned and transmuted. JAEA and Toshiba developed process for recovering Se, Zr, Pd and Cs from HLLW. Solvent extraction for Zr with novel extractant, ${it N,N}$-didodecyl-2-hydroxyacetoamide (HAA) was detailed. The HAA system showed high selectivity for Zr, as indicated by the extraction order of Zr $$>$$ Mo $$>$$ Pd $$>$$ Ag $$approx$$ Sb $$>$$ Sn $$>$$ Lns $$>$$ Fe. The extracted species was determined as Zr(HAA)$$_{3}$$(NO$$_{3}$$)$$_{4}$$(HNO$$_{3}$$)$$_{x}$$. A continuous countercurrent extraction with HAA was applied to a simulated, concentrated HLLW after Pd, Se, and Cs removal, where the quantitative extraction of Zr and Mo was effectively demonstrated.

Journal Articles

Extractions and spectroscopic studies of various metals with Diglycolamide-Type Tridentate Ligands

Sasaki, Yuji; Saeki, Morihisa*; Yoshizuka, Kazuharu*

Solvent Extraction Research and Development, Japan, 26(1), p.21 - 34, 2019/06

 Times Cited Count:5 Percentile:38.21(Chemistry, Multidisciplinary)

Three tridentate extractants and three masking reagents including O, N, and S donors have been developed and their properties are compared and discussed. The extractants are termed as tetraoctyl-diglycolamide (TODGA), methylimino-dioctylacetamide (MIDOA) and tetraoctyl-thiodiglycolamide (TDGA(C8)) and masking agents have the same central frame but with short alkyl chain. The results of the present study indicate that TODGA can extract mainly hard acid metals belonging groups 2-4,13-15 in periodic table, MIDOA can extract soft acid metals and oxyanions (groups 5-10, 16), and TDGA can extract soft acid metals (groups 10-11). Some spectrophotometric studies (UV, IR, and NMR) indicate the stoichiometry and effect of donor atoms for metal-complexation. The Hf values, the heat generation during complex formation, obtained by chemical calculation by DFT theory show the reverse-correlation with their extraction ability.

Journal Articles

Extraction of trivalent rare earths and minor actinides from nitric acid with ${it N,N,N',N'}$-tetradodecyldiglycolamide (TDdDGA) by using mixer-settler extractors in a hot cell

Ban, Yasutoshi; Suzuki, Hideya; Hotoku, Shinobu; Kawasaki, Tomohiro*; Sagawa, Hiroshi*; Tsutsui, Nao; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 37(1), p.27 - 37, 2019/00

 Times Cited Count:12 Percentile:68.99(Chemistry, Multidisciplinary)

A continuous counter-current experiment using TDdDGA was performed using mixer-settler extractors installed in a hot cell. Nitric acid containing minor actinides (MAs: Am and Cm), rare earths (REs: Y, La, Nd, and Eu), and other fission products (Sr, Cs, Zr, Mo, Ru, Rh, and Pd) was fed to the extractor. TDdDGA effectively extracted MAs and REs from the feed, while other fission products were barely extracted. The extracted MAs and REs were back-extracted by bringing them in contact with 0.02 mol/dm$$^{3}$$ nitric acid, and they were collected as the MA-RE fraction. The proportions of MA and RE in the MA-RE fraction were $$>$$ 98% and $$>$$ 86%, respectively. These results demonstrated the applicability of TDdDGA as an extractant for MAs and REs.

Journal Articles

Solvent extraction in analytical separation techniques

Shimojo, Kojiro

Analytical Sciences, 34(12), p.1345 - 1346, 2018/12

Solvent extraction is one of the most effective analytical methods for separation, purification, and removal of target metal ions (e.g. valuable metal ions, toxic metal ions and radioactive fission products) from aqueous solutions containing various metal ions. In this paper, we introduce the papers related to (1) novel extractant, (2) ionic liquids and deep eutectic solvents, (3) new extractors, among papers on solvent extraction published between 2016 and 2018.

Journal Articles

Mechanism of phase transfer of uranyl ions; A Vibrational sum frequency generation spectroscopy study on solvent extraction in nuclear reprocessing

Kusaka, Ryoji; Watanabe, Masayuki

Physical Chemistry Chemical Physics, 20(47), p.29588 - 29590, 2018/12

 Times Cited Count:10 Percentile:67.09(Chemistry, Physical)

Mechanistic understanding of solvent extraction of uranyl ions (UO$$_{2}$$$$^{2+}$$) by tributyl phosphate (TBP) will help improve the technology for the treatment and disposal of spent nuclear fuels. So far, it has been believed that uranyl ions in the aqueous phase are adsorbed to a TBP-enriched organic/aqueous interface, form complexes with TBP at the interface, and are extracted into the organic phase. Here we show that uranyl-TBP complex formation does not take place at the interface using vibrational sum frequency generation (VSFG) spectroscopy and propose an alternative extraction mechanism that uranyl nitrate, UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$, passes through the interface and forms the uranyl-TBP complex, UO$$_{2}$$(NO$$_{3}$$)$$_{2}$$(TBP)$$_{2}$$, in the organic phase.

Journal Articles

CFD analysis for U extraction in a centrifugal contactor

Sano, Yuichi; Sakamoto, Atsushi; Kofuji, Hirohide; Takeuchi, Masayuki

Proceedings of 21st Pacific Basin Nuclear Conference (PBNC 2018) (USB Flash Drive), p.314 - 318, 2018/09

The effect of operational condition of the annular centrifugal contactor (ACC) on U extraction behavior was investigated by computational fluid dynamics (CFD) analysis considering mass transfer between aqueous and organic phases, and the calculation results were validated experimentally. The CFD analysis with ANSYS FLUENT was carried out using the Eulerian multi-fluid approach with a standard k-$$varepsilon$$ turbulence model. In order to calculate the droplet size of the dispersed phase and mass transfer between aqueous and organic phases, user-defined functions (UDF) were created. The changes of U extraction performance, i.e. U stage efficiency, with the rotor speed and the O/A ratio (= organic flowrate / aqueous flowrate) were calculated, and these showed a good agreement with experimental results.

Journal Articles

The Structure of a lanthanide complex at an extractant/water interface studied using heterodyne-detected vibrational sum frequency generation

Kusaka, Ryoji; Watanabe, Masayuki

Physical Chemistry Chemical Physics, 20(4), p.2809 - 2813, 2018/01

 Times Cited Count:8 Percentile:58.11(Chemistry, Physical)

Solvent extraction plays an integral part in the separation and purification of metals. Because extractants generally used as complexing agents for metal extractions, such as di-(2-ethylhexyl)phosphoric acid (HDEHP) for lanthanide extractions, are amphiphilic, they come to the organic/water interface, and the interface plays a crucial role as the site of the formation of metal complexes and subsequent transfer reaction to an organic phase. Despite the importance of the interface for solvent extractions, however, molecular-level structure of the interface is unclear because of experimental difficulty. Here we studied structure of a trivalent europium (Eu$$^{3+}$$) complex with HDEHP formed at HDEHP monolayer/water interface by heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. The study on the HDEHP/water interface enables us to investigate the structure of the interfacial Eu$$^{3+}$$ complex by excluding the migration of Eu$$^{3+}$$ into an organic phase after the complex formation at the interface. The interface-selective vibrational Im$$chi$$$$^{(2)}$$ spectra observed by HD-VSFG of HDEHP/Eu(NO$$_{3}$$)$$_{3}$$ aqueous solution interface in the 2800-3500 cm$$^{-1}$$ region indicate that Eu$$^{3+}$$ at the HDEHP/water interface is bonded by HDEHP from the air side and by water molecules from the water side. To the best of our knowledge, such metal complex structures have not been identified in the organic or water solutions.

Journal Articles

Actinides recovery from irradiated fuel for SmART cycle

Sano, Yuichi; Watanabe, So; Nakahara, Masaumi; Aihara, Haruka; Takeuchi, Masayuki

Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 4 Pages, 2017/09

JAEA has been promoting MA recycle project using a FR fuel cycle named as SmART cycle concept. The SmART cycle contains the recovery of all actinides, in which total amount of MA is estimated to around 1-2g, at CPF from the FR Joyo spent fuel, the fabrication of MA bearing MOX fuel pellets and pins at AGF with recovered actinides, and the irradiation test of the fabricated fuels at the Joyo. In this paper, recent activities on actinides recovery in CPF, which will make a significant contribution to the SmART cycle, were summarized.

Journal Articles

Solvent extraction of uranium with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Sagawa, Hiroshi; Ishii, Sho; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 35(6), p.439 - 449, 2017/08

 Times Cited Count:3 Percentile:18.22(Chemistry, Multidisciplinary)

Solvent extraction of uranium from a nitric acid medium was performed with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide (DEHOA) by a single-stage batch method, and the distribution ratio equation of U(VI) was derived as $${it D}_{rm U}$$ = 1.1$$[rm NO^{-}_{3}]^{1.6}_{rm aq}[{rm DEHOA}]^{2}_{rm org}$$. Furthermore, the nitric acid distribution was also evaluated, and the distribution ratio equation $${it D}_{rm H}$$ = 0.12$$[rm H^{+}]^{0.76}_{rm aq}[{rm DEHOA_{rm Free}}]_{rm H}$$ was obtained. Batch experiments to evaluate the time dependence of U(VI) extraction and the U(VI) loading capacity of DEHOA were also performed. It was revealed that U(VI) extraction by DEHOA reached an equilibrium state within a few minutes, and the loading capacity was 0.71 mol/dm$$^{3}$$ (M) when the concentrations of DEHOA and nitric acid were 1.5 and 3.0 M, respectively.

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