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Journal Articles

Mutual separation of Am and Cm using ADAAM (alkyl DiAmide AMine) and reduction of volumes for liquid waste generated via batch-wise multistage extractions

Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Suzuki, Hideya*

Journal of Nuclear Science and Technology, 61(7), p.883 - 893, 2024/07

 Times Cited Count:2 Percentile:59.55(Nuclear Science & Technology)

The mutual separation of Am and Cm is conducted using an alkyl-diamide amine (ADAAM) extractant. ADAAM exhibits extremely high separation factor with respect to Am and Cm separation (5.9) in a nitric acid-$$n$$-dodecane system. The batch-wise multistage extractions are performed using a system containing 0.2 M ADAAM and 1.5 M nitric acid. In this multistage extraction, an organic solvent give 96.5% and 1.06% yields of Am and Cm. After the mutual separation of Am and Cm, an additional extraction step is included to reduce the volumes of these aqueous and organic phases. Taking these steps, Am and Cm can be recovered in just two or three stages in the aqueous phases.

Journal Articles

Organization of malonamides from the interface to the organic bulk phase

Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Akutsu, Kazuhiro*; Yamada, Norifumi*; Yamada, Masako*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.

Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05

 Times Cited Count:1 Percentile:65.37(Chemistry, Physical)

Journal Articles

Overview of development program for engineering scale extraction chromatography MA(III) recovery system

Watanabe, So; Takahatake, Yoko; Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Mechanical Engineering Journal (Internet), 11(2), p.23-00461_1 - 23-00461_10, 2024/04

Journal Articles

Ion-pairing extraction and their reaction modeling of anionic M-Cl species with cationic NTAamide(C6) extractant and comparison with density functional theory calculations

Kinoshita, Ryoma; Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*

Hydrometallurgy, 222, p.106159_1 - 106159_12, 2023/10

 Times Cited Count:1 Percentile:18.99(Metallurgy & Metallurgical Engineering)

Solvent extraction is conducted using a total of 20 metals revealing high stability constants with Cl and hexahexyl-nitrilotriacetamide (NTAamide(C6)) extractant. The metals used here may behave as anions at high Cl concentrations, and NTAamide(C6), which contains a tertiary N atom, is protonated under acidic conditions. Most of the metal ions in this study display higher distribution ratios (D(M)) from HCl than those from HNO$$_{3}$$, and exhibit 1:1 stoichiometries with NTAamide. Following the experimental results, the association constants and distribution coefficients of the group 12 elements are calculated via ion-pair extraction modeling using density functional theory calculations, and the simulations of D yield calculated values with the same trend as that of the measured values.

Journal Articles

Extraction of Rh(III) from hydrochloric acid by protonated NTAamide(C6) and analogous compounds and understanding of extraction equilibria by using UV spectroscopy and DFT calculations

Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Kinoshita, Ryoma; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*

Analytical Sciences, 39(9), p.1575 - 1583, 2023/09

 Times Cited Count:1 Percentile:18.58(Chemistry, Analytical)

Extraction of Rh from HCl can be performed by NTAamide(C6) (hexahexyl-nitrilotriacetamide) and other related compounds into n-dodecane. We use ion-pair extraction of anionic species of Rh-chloride and protonated extractant. Rh behave as anion in hydrochloric acid and the tertiary nitrogen atom in extractant may be protonated to produce the quaternary amine in acidic condition. From the present work, the maximum distribution ratio of Rh(III) is 16. The D(Rh) values are changeable during preparation of the aqueous solutions because different Rh-Cl-H$$_{2}$$O complexes are formed in HCl media and show the slow exchange rate between Cl and H$$_{2}$$O. Using the UV spectrum, Rh-chloride solution having the peak of spectrum at 504 nm can be extracted effectively, where RhCl$$_{4}$$(H$$_{2}$$O)$$^-$$ and RhCl$$_5$$(H$$_2$$O)$$^2$$$$^-$$ exist mainly from DFT calculation. Stoichiometry of one-one complex of Rh and NTAamide is obtained from slope analysis, and 85 mM of concentrated Rh ion can be extracted.

Journal Articles

Evaluation of the remaining spent extraction solvent in vermiculite after leaching tests via PIXE analysis

Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*

Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09

 Times Cited Count:1 Percentile:35.91(Instruments & Instrumentation)

Journal Articles

Extraction of Se(iv) and Se(vi) from aqueous HCl solution by using a diamide-containing tertiary amine

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

RSC Advances (Internet), 13(25), p.17001 - 17007, 2023/06

 Times Cited Count:3 Percentile:46.20(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Treatment of U contaminated waste generated from nuclear fuel fabrication process, 1; Ce(IV) recovery by temperature swing extraction with monoamides

Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05

Applicability of temperature swing extraction technology employing monoamides was examined for uranium contaminated waste treatment procedure. Separation experiments on simulated target solution with three kinds of monoamides with different structure showed that Ce(IV) in the solution was selectively recovered by the temperature swing extraction operation. Based on the experiments, an appropriate monoamide for the procedure was selected.

Journal Articles

Combining a lipophilic phenanthroline carboxamide and a hydrophilic diglycolamide to increase the separation factors of adjacent light lanthanides

Simonnet, M.; Sasaki, Yuji; Yaita, Tsuyoshi

Solvent Extraction and Ion Exchange, 41(7), p.857 - 867, 2023/00

 Times Cited Count:2 Percentile:33.15(Chemistry, Multidisciplinary)

Journal Articles

Cs extraction from chloride media by calixarene crown-ethers

Simonnet, M.; Sittel, T.*; We${ss}$ling, P.*; Geist, A.*

Energies (Internet), 15(20), p.7724_1 - 7724_10, 2022/10

 Times Cited Count:3 Percentile:18.11(Energy & Fuels)

Journal Articles

Investigation of total separations using solvent extraction of actinides and fission products

Sasaki, Yuji

Bunri Gijutsu, 52(2), p.103 - 107, 2022/03

We develop all-inclusive partitioning method for actinides and fission products in high-level radioactive waste. This process is based on the sequential solvent extraction. In order to recover Cs and Sr for the management by interim storage, crown ether compounds are employed. For the removal of Pd and Mo due to production of a stable vitrified object, methylimino-dioctylacetamide (MIDOA) is taken as an extractant. DGA can extract both actinides and trivalent lanthanides. In order to separate each other, dietylenetriamine-triacetic-diamide (DTBA) for the stripping reagent of MA. For the mutual separation of Am/Cm, DGA and DOODA extraction system is taken into consideration.

Journal Articles

Separation of light and middle lanthanides using multistage extraction with diglycolamide extractant

Matsutani, Takafumi; Sasaki, Yuji; Katsuta, Shoichi*

Analytical Sciences, 37(11), p.1603 - 1609, 2021/11

 Times Cited Count:7 Percentile:43.03(Chemistry, Analytical)

We investigated the chemical behavior of lanthanides (Ln) using diglycolamide extractant with multistage extraction. We obtained the breakthrough curves for light and middle Ln. Our study reveals that the metal extraction limit depends on their $$D$$ values and metal concentrations used in the experiments. From the multistage extractions of 15 aqueous phases and 15 organic phases, three curves (extraction curves, back-extraction curves, and separation curves) were obtained by changing the nitric acid concentration. As an example, under a condition of the separation curve experiment (aqueous phase: 0.5 M HNO$$_{3}$$, organic phase: 0.1 M TDDGA ($$N,N,N',N'$$-tetradecyl-diglycolamide) in $$n$$-dodecane), a recovery of more than 99% of Sm in the organic phase with less than 1% Nd can be obtained.

Journal Articles

Additive-free hydrothermal leaching method with low environmental burden for screening of strontium in soil

Kato, Takuma*; Nagaoka, Mika; Guo, H.*; Fujita, Hiroki; Aida, Taku*; Smith, R. L. Jr.*

Environmental Science and Pollution Research, 28(39), p.55725 - 55735, 2021/10

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

In this work, hydrothermal leaching was applied to simulated soils (clay minerals vermiculite, montmorillonite, kaolinite) and actual soils (Terunuma, Japan) to generate organic acids with the objective to develop an additive-free screening method for determination of Sr in soil. Stable strontium (SrCl$$_{2}$$) was adsorbed onto soils for study and ten organic acids were evaluated for leaching Sr from simulated soils under hydrothermal conditions (120 to 200$$^{circ}$$C) at concentrations up to 0.3 M. For strontium-adsorbed vermiculite (Sr-V), 0.1 M citric acid was found to be effective for leaching Sr at 150$$^{circ}$$C and 1 h treatment time. Based on these results, the formation of organic acids from organic matter in Terunuma soil was studied. Hydrothermal treatment of Terunuma soil produced a maximum amount of organic acids at 200$$^{circ}$$C and 0.5 h reaction time. To confirm the possibility for leaching of Sr from Terunuma soil, strontium-adsorbed Terunuma soil (Sr-S) was studied. For Sr-S, hydrothermal treatment at 200$$^{circ}$$C for 0.5 h reaction time allowed 40% of the Sr to be leached at room temperature, thus demonstrating an additive-free method for screening of Sr in soil. The additive-free hydrothermal leaching method avoids calcination of solids in the first step of chemical analysis and has application to both routine monitoring of metals in soils and to emergency situations.

Journal Articles

Study on phenanthroline carboxamide for lanthanide separation; Influence of amide substituents

Simonnet, M.; Kobayashi, Toru; Shimojo, Kojiro; Yokoyama, Keiichi; Yaita, Tsuyoshi

Inorganic Chemistry, 60(17), p.13409 - 13418, 2021/09

 Times Cited Count:22 Percentile:90.36(Chemistry, Inorganic & Nuclear)

Journal Articles

Fundamental study on multistage extraction using TDdDGA for separation of lanthanides present in Nd magnets

Sasaki, Yuji; Morita, Keisuke; Matsumiya, Masahiko*; Ono, Ryoma*; Shiroishi, Hidenobu*

JOM, 73(4), p.1037 - 1043, 2021/04

 Times Cited Count:4 Percentile:33.94(Materials Science, Multidisciplinary)

The separation of Dy from Nd is studied from the viewpoint of recycling Dy from Nd magnets. Both metals are lanthanide elements, which means their mutual separation is difficult because of their similar chemical behaviors. All lanthanide elements can be extracted easily by using tetradodecyl-diglycolamide (TDdDGA) extractants, and it has a relatively high separation factor (SF) between Dy and Nd (SF over 10). In the present study, by performing eight extraction steps with the organic phase (0.1M TDdDGA in dodecane), ten steps with an aqueous phase (0.7 M HNO$$_{3}$$ with metals), and six steps with another aqueous phase (0.7 M HNO$$_{3}$$ without metals), approximately 99% Dy was recovered into the organic phase with 1% co-extraction of Nd.

Journal Articles

Development of HCl-free solid phase extraction combined with ICP-MS/MS for rapid assessment of difficult-to-measure radionuclides, 1; Selective measurement of $$^{93}$$Zr and $$^{93}$$Mo in concrete rubble

Do, V. K.; Furuse, Takahiro; Murakami, Erina; Aita, Rena; Ota, Yuki; Sato, Soichi

Journal of Radioanalytical and Nuclear Chemistry, 327(1), p.543 - 553, 2021/01

 Times Cited Count:5 Percentile:54.24(Chemistry, Analytical)

A new HCl-free chromatographic separation procedure has been developed for sequential separation of Zr and Mo from concrete matrices. Accordingly, $$^{93}$$Zr and $$^{93}$$Mo could be sensitively and selectively measured by ICP-MS/MS using ammonia reaction gas. The recoveries of greater than 90% for Zr and Mo from concretes could be achieved. The measurement condition was optimized for complete suppression of interferences from $$^{93}$$Nb and peak tailing from abundant isotopes of Zr and Mo in concrete matrices. The removal of interferences was verified by measurement of radio-contamination-free concretes used as a sample matrix blank. Method detection limits of 1.7 mBq g$$^{-1}$$ and 0.2 Bq g$$^{-1}$$ were achieved for $$^{93}$$Zr and $$^{93}$$Mo, respectively, in the concrete matrices. The interference removal factor for Nb (equivalent to the decontamination factor in radiochemical separation) was of the order of 10$$^{5}$$, and the abundance sensitivity was of the order of 10$$^{-8}$$, indicating that the developed method is reliable for verifying the presence of ultralow concentrations of $$^{93}$$Zr and $$^{93}$$Mo. The present method is suitable for the rapid assessment of $$^{93}$$Zr and $$^{93}$$Mo for radioactivity inventory of concrete rubble.

Journal Articles

Solvent extraction of cesium using DtBuDB18C6 into various organic solvents

Sasaki, Yuji; Morita, Keisuke; Kitatsuji, Yoshihiro; Ito, Keisuke*; Yoshizuka, Kazuharu*

Solvent Extraction Research and Development, Japan, 28(2), p.121 - 131, 2021/00

 Times Cited Count:2 Percentile:10.43(Chemistry, Multidisciplinary)

High concentration of Cs is present in high-level radioactive waste. It is well-known that Cs is an alkali element and difficult to extract completely into an organic phase. Crown ether compounds are widely available for Cs extractants; DtBuDB18C6 (di-$$t$$-butyl-dibenzo-18crown6), was used in this study. Organic solvents used for the industrial applications, such as $$n$$-dodecane and 1-octanol, have low solubility concerning the compound; other solvents were employed and tested. In this study, ketone-, ether-, and ester-type solvents showed high solubility for DtBuDB18C6 and DtBuDB18C6, when dissolved in ketones and alcohols, exhibited relatively high Cs distribution ratios ($$D$$(Cs)), closely to 10.

Journal Articles

Study on the mechanism of radiolytic degradation of an extractant for minor actinides separation

Toigawa, Tomohiro; Murayama, Rin*; Kumagai, Yuta; Yamashita, Shinichi*; Suzuki, Hideya; Ban, Yasutoshi; Matsumura, Tatsuro

UTNL-R-0501, p.24 - 25, 2020/12

This report summarizes the results obtained in FY2019 at Electron Linac Facility of University of Tokyo. The radiolysis process of a diglycolamide extractant, which is expected to be used in the separation process of minor actinides (MA), in dodecane and octanol solutions was investigated by pulse radiolysis. As a result, it was suggested that by adding alcohol, the decomposition process of the diglycolamide extractant was different from the decomposition processes in the single solvent of dodecane considered that the decomposition occurred via a radical cation species of the extractant.

Journal Articles

Solvent extraction of platinum group metals from urban mine by diglycolamide with soft donor atoms

Sasaki, Yuji; Nakase, Masahiko*

Petorotekku, 43(11), p.782 - 787, 2020/11

As analog compounds of DGA (diglycolamide), MIDOA(methylimino-diacetamide) and TDGA(thia-diglycolammide) are used for the extractants of platinum group metals. These extractants can be extracted noble metals and oxyanions, which followed by HSAB theory. The high concentration of these metals can be also extracted by these compounds. The research of metal-complex structures gives the information on the ability and role for complex-formation, which will be useful for the development of novel extractants.

Journal Articles

Simultaneous separation of Am and Cm from Nd and Sm by multi-step extraction using the TODGA-DTPA-BA-HNO$$_{3}$$ system

Sasaki, Yuji; Morita, Keisuke; Matsumiya, Masahiko*; Nakase, Masahiko*

Radiochimica Acta, 108(9), p.689 - 699, 2020/09

 Times Cited Count:9 Percentile:68.58(Chemistry, Inorganic & Nuclear)

The simultaneous separation of Am and Cm from lanthanides is important for atomic energy fields. All lanthanides, Am, and Cm can be extracted by diglycolamide (DGA). In addition, relatively high separation factors between An and Ln were obtained by the extraction system of TODGA, DTPA (diethylenetriamine-pentaacetic acid) and HNO$$_{3}$$. In this work, DTPA-BA (diethylenetriamine-triacetic-bisamide), which is an improved version of DTPA, was employed for the separation of Ln and An. A relatively high separation factor (approximately 8) for actinides/lanthanides was obtained. Then, the multi-step extraction was performed. Thus, the recoveries of 94.7% for Nd and 4.7% for Am and Cm in organic phase, and 5.3% Nd and 95.3% for Am and Cm in aqueous phase were obtained.

201 (Records 1-20 displayed on this page)