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Journal Articles

Development of MA separation process with TEHDGA/SiO$$_{2}$$-P for an advanced reprocessing

Horiuchi, Yusuke; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Kida, Fukuka*; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 330(1), p.237 - 244, 2021/10

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

Applicability of tetra2-ehylhexyl diglycolamide (TEHDGA) impregnated adsorbent for minor actinide (MA) recovery from high level liquid waste (HLLW) in extraction chromatography technology was investigated through batch-wise adsorption and column separation experiments. Distribution ratio of representative fission product elements were obtained by the batch-wise experiments, and TEHDGA adsorbent was shown to be preferable to TODGA adsorbent for decontamination of several species. All Ln(III) supplied into the TEHDGA adsorbent packed column was properly eluted from the column, and the applicability of the adsorbent was successfully showed by this study.

JAEA Reports

Evaluation of the mass transfer coefficients for the minor actinide separation; Evaluation by the single drop method

Sakamoto, Atsushi; Kibe, Satoshi*; Kawanobe, Kazunori*; Fujisaku, Kazuhiko*; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya*; Tsubata, Yasuhiro; Ban, Yasutoshi; Matsumura, Tatsuro

JAEA-Research 2021-003, 30 Pages, 2021/06

JAEA-Research-2021-003.pdf:1.81MB

Japan Atomic Energy Agency has been developing a solvent extraction process called SELECT to recover minor actinides (MA) from spent nuclear fuel. In the SELECT process, TDdDGA, HONTA, and ADAAM are used as the extractants for MA + Ln corecovery, MA/Ln separation and Am/Cm separation, respectively. These extractants do not contain phosphorus (P), and consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). In this study, in order to give beneficial information for designing flowsheet, the mass transfer coefficients of Ln between HNO$$_{3}$$ solution and TDdDGA or HONTA / n-dodecane solvent were evaluated by the single drop technique. Prior to the evaluation of mass transfer coefficient, we had optimized the structure of the single drop apparatus to improve accuracy of the measurement. Based on the mass transfer coefficients obtained in HNO$$_{3}$$ / TDdDGA-n-dodecane system, Ln behaviors in the counter-current extraction and back-extraction using mixer-settlers and centrifugal contactors were estimated by simple calculation, and they had a good agreement with our previous experimental results. We also confirmed the mass transfer coefficients of Ln in HNO$$_{3}$$ / HONTA - n-dodecane system are under 10$$^{-6}$$ m/s.

Journal Articles

Re-evaluation of radiation-energy transfer to an extraction solvent in a minor-actinide-separation process based on consideration of radiation permeability

Toigawa, Tomohiro; Tsubata, Yasuhiro; Kai, Takeshi; Furuta, Takuya; Kumagai, Yuta; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 39(1), p.74 - 89, 2021/00

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

Absorbed-dose estimation is essential for evaluation of the radiation feasibility of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha ray depends upon the emulsion structure, and that from beta and gamma ray depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.

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

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:43.69(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

Theoretical elucidation of Am(III)/Cm(III) separation mechanism with diamide-type ligands using relativistic density functional theory calculation

Kaneko, Masashi; Suzuki, Hideya; Matsumura, Tatsuro

Inorganic Chemistry, 57(23), p.14513 - 14523, 2018/12

 Times Cited Count:10 Percentile:70.56(Chemistry, Inorganic & Nuclear)

We elucidated the separation mechanism between Am(III) and Cm(III) ions by using two different types of diamide ligands, diglycolamide (DGA) and alkylated diamide amine (ADAAM), by means of the density functional theory technique and electron density analysis. The molecular geometries and formation reactions of the metal-ligand complexes were modeled by using [M(DGA)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)]. We successfully reproduced Cm(III) selectivity over Am(III) with DGA and Am(III) selectivity over Cm(III) with ADAAM. Furthermore, we analyzed the bonding properties between the metal ion and the diamide-type ligands by using model complexes, [M(DGA)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)], and revealed the differences in terms of the bond dissociation energy and the metal 5f-orbital participation in the covalency between the Am(III) and the Cm(III) complexes. It was suggested that the differences were key factors to understand the Am(III)/Cm(III) selectivity.

Journal Articles

Mutual separation of trivalent lanthanide and actinides by hydrophilic and lipophilic multidentate diamides

Sasaki, Yuji; Morita, Keisuke

Progress in Nuclear Science and Technology (Internet), 5, p.27 - 32, 2018/12

no abstracts in English

Journal Articles

Metal extractions by diglycolamide-type tridentate ligands

Sasaki, Yuji; Morita, Keisuke; Saeki, Morihisa*; Hisamatsu, Shugo*; Yoshizuka, Kazuharu*

Proceedings of 21st International Solvent Extraction Conference (ISEC 2017) (Internet), p.131 - 134, 2017/11

Three tridentate extractants including soft and hard donor has been developed and examined. The extractants are termed as $$N, N, N', N'$$-tetraoctyl-diglycolamide (TODGA), methylimino-$$N, N'$$-dioctylacetamide (MIDOA) and $$N, N, N', N'$$-tetraoctyl-thiodiglycolamide (TDGA). The results of the present study show that TODGA can extract completely lanthanides and actinides, MIDOA can extract palladium, technetium, and rhenium, and TDGA can extract palladium, silver, and gold. We can compare the distribution ratios of these metals by TODGA, MIDOA, and TDGA. These results can be supported by some spectrometric studies, i.e., IR, NMR and UV, and calculations of metal complexes.

Journal Articles

Reduction and resource recycling of high-level radioactive wastes through nuclear transmutation; Isolation techniques of Pd, Zr, Se and Cs in simulated high level radioactive waste using solvent extraction

Sasaki, Yuji; Morita, Keisuke; Ito, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Takahashi, Yuya*; Kaneko, Masaaki*; Omori, Takashi*; Asano, Kazuhito*

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

no abstracts in English

Journal Articles

Precious metal extraction by N,N,N',N'-tetraoctyl-thiodiglycolamide and its comparison with N,N,N',N'-tetraoctyl-diglycolamide and methylimino-N,N'-dioctylacetamide

Sasaki, Yuji; Morita, Keisuke; Saeki, Morihisa*; Hisamatsu, Shugo; Yoshizuka, Kazuharu*

Hydrometallurgy, 169, p.576 - 584, 2017/05

 Times Cited Count:10 Percentile:59.14(Metallurgy & Metallurgical Engineering)

The novel tridentate extractant including soft donor has developed and examined. The extractant, tetraoctyl-thiodiglycolamide (TDGA), is analogous structure to tetraoctyl-diglycolamide (TODGA) and methylimino-dioctylacetamide (MIDOA), but with sulfur donor instead of ether oxygen or nitrogen atoms of TODGA or MIDOA. From the present work, TDGA can extract silver, palladium, gold, and mercury from acidic solutions to n-dodecane. In addition to these results, the distribution ratios of hard and soft acid metals by using TDGA, TODGA, and MIDOA are compared, where the metal-complexations with each donor atom are investigated. 1H-NMR and IR studies for the metal-TDGA complexes indicate the role on donor atoms, S and N, of TDGA.

Journal Articles

Solvent extraction of metal ions using a new extractant, biuret(C8)

Sasaki, Yuji; Yoshimitsu, Ryo*; Nishihama, Shohei*; Shimbori, Yuma*; Shiroishi, Hidenobu*

Separation Science and Technology, 52(7), p.1186 - 1192, 2017/03

 Times Cited Count:2 Percentile:12.88(Chemistry, Multidisciplinary)

The new extractant, biuret(C8), is synthesized and tested for the solvent extraction of hard acid metals like actinides and soft acid metals. This compound has the similar central frame to malonamide but with 2-NH introduced into the central frame, then both amidic oxygen and nitrogen atoms may bond with metals. From the present work, not only hard acid metals, but also soft acid metals can be extracted by biuret(C8) from nitric or perchloric acids to n-dodecane. The extractability for biuret(C8) is compared with other representative extractants, malonamide, TODGA and MIDOA. It is clear that the distribution ratio(D) of U and Pu by biuret(C8) is similar to those for malonamide, but with lower values than those for TODGA and MIDOA, and D for soft acid metals and oxonium anions show higher values than those for TODGA and malonamide and lower than those for MIDOA.

JAEA Reports

Countercurrent extraction/stripping experiments using TDdDGA solvent extractant in a centrifugal contactor system,2; Evaluation on the improved flowsheet for MA recovery

Kibe, Satoshi; Fujisaku, Kazuhiko*; Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro

JAEA-Research 2016-024, 40 Pages, 2017/02

JAEA-Research-2016-024.pdf:6.73MB

The Japan Atomic Energy Agency has been developing some flowsheets with TDdDGA (N,N,N,Ntetradodecyldiglycolamide) extractant to recover MA (minor actinide) from raffinate. In this study, countercurrent experiments with the improved flowsheet, e.g. the addition of alcohol into the solvent for preventing the precipitation, were performed using miniature centrifugal contactors in order to compare the extraction/stripping behavior of each element with the mixer-settler type. As a result, no entrainments were observed and sufficient phase separation was achieved by centrifugal contactors without any abnormal fluid behavior, such as overflow. The extraction and stripping of Ln(III) which show the similar tendencies as MA could be achieved successfully, especially their stripping proceeded more efficiently in centrifugal contactors. This might be due to the increase in stripping rates by improving the flowsheet and to superior phase separation performance of centrifugal contactors.

Journal Articles

Effect of surface treatment on adsorption and desorption behavior of impregnated adsorbent for extraction chromatography

Nagoshi, Kohei*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Sato, Mutsumi*; Oikawa, Hiroshi*

Nihon Ion Kokan Gakkai-Shi, 28(1), p.11 - 18, 2017/01

no abstracts in English

Journal Articles

The Separation mechanism of Am(III) from Eu(III) by diglycolamide and nitrilotriacetamide extraction reagents using DFT calculations

Kaneko, Masashi; Watanabe, Masayuki; Matsumura, Tatsuro

Dalton Transactions, 45(43), p.17530 - 17537, 2016/11

AA2016-0311.pdf:1.49MB

 Times Cited Count:26 Percentile:88.4(Chemistry, Inorganic & Nuclear)

Relativistic density functional calculations were applied to study the separation behaviors of Am(III) ion from Eu(III) ion by diglycolamide (DGA) and nitrilotriacetamide (NTA) ligands in order to understand the difference in the separation mechanism of their reagents. The complexation reaction was modeled on the basis of previous experimental studies. The calculated energies based on stabilization by complex formation at the ZORA-B2PLYP/SARC level predicted that the DGA reagent preferably coordinated to Eu(III) ion when compared with Am(III) ion. In contrast, the NTA reagent selectively coordinated to Am(III) ion when compared with Eu(III) ion. These results reproduced the experimental selectivity of DGA and NTA ligands toward Eu(III) and Am(III) ions. Mulliken's population analyses implied that the difference in the contribution of the bonding property between the f-orbital of Am and donor atoms determined the comparative stability of Eu and Am complexes.

JAEA Reports

Countercurrent extraction/stripping experiments using TDdDGA solvent extractant in a centrifugal contactors system

Kibe, Satoshi; Fujisaku, Kazuhiko*; Ambai, Hiromu; Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro

JAEA-Research 2015-021, 40 Pages, 2016/02

JAEA-Research-2015-021.pdf:2.3MB

The flowsheet with TDdDGA extractant has been being developed for recovering MA from PUREX raffinate. In the previous study, the yields of MA and other elements in countercurrent extraction/stripping experiments using mixer-settlers were not enough for the target and it would be due to the insufficient phase (aqueous/organic) separation. In this study, we carried out countercurrent experiments with surrogate PUREX raffinate using centrifugal contactors which had superior phase separation ability, and evaluated the extraction/stripping behavior of each element. During the operation, abnormal fluid behavior, such as overflow and entrainment, was not observed, and sufficient phase separation was achieved by centrifugal contactors. Extraction behavior of lanthanides was similar to that in mixer-settlers, but their stripping efficiencies decreased. This would be due to shorter residence time in mixing zone.

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

New water-soluble organic ligands for Actinide cations complexation

Sasaki, Yuji; Suzuki, Hideya*; Sugo, Yumi; Kimura, Takaumi; Choppin, G. R.*

Chemistry Letters, 35(3), p.256 - 257, 2006/03

 Times Cited Count:31 Percentile:66.24(Chemistry, Multidisciplinary)

Novel water-soluble organic ligands, N,N,N',N'-tetramethyl-diglycolamide (TMDGA), N,N,N',N'-tetraethyl-diglycolamide (TEDGA), N,N,N',N'-tetrapropyl-diglycolamide (TPDGA) and N,N-dipropyl-diglycolamic acid (DPDGAc), were synthesized and examined for complexation with An(III) and An(IV). These reagents are readily soluble in water and form more stable complexes with Pu(IV) and Am(III) than does EDTA of hexadentate ligand. TEDGA and TPDGA can back-extract effectively An into the aqueous phase. In addition, the An-complex in the aqueous phase can be dissociated and the TEDGA can be separated from the An and recovered by extraction using a polar organic solvent.

Journal Articles

Extraction capacity of diglycolamide derivatives for Ca(II), Nd(III) and Zr(IV) from nitric acid to $$n$$-dodecane containing a solvent modifier

Sasaki, Yuji; Zhu, Z.-X.; Sugo, Yumi; Suzuki, Hideya*; Kimura, Takaumi

Analytical Sciences, 21(10), p.1171 - 1175, 2005/10

 Times Cited Count:26 Percentile:60.4(Chemistry, Analytical)

In order to evaluate the extraction property of the new extractants, diglycolamide(DGA) compounds, we investigated the maximum extraction of di-, tri-, and tetravalent metal ions using the system of nitric acid and n-dodecane. Limits of metal concentration (LOC) for Ca(II), Nd(III) and Zr(IV) influence strongly on HNO$$_{3}$$ and the extractant concentration. On the purpose to raise the LOC value, we employed the modifier of solvent, N,N-dihexyl-octanamide(DHOA) and DGA with the long alkyl chain, and examined. It is evident that LOC increases with DHOA concentration in n-dodecane and the length of alkyl chain attached with N atom of DGA. The stoichiometric values of LOC(Zr) estimated from the extraction reaction is obtained by using the extraction condition: tetraoctyl-DGA/ 1M DHOA+n-dodecane and 3M HNO$$_{3}$$.

Journal Articles

Novel compounds, Diglycolamides (DGA), for extraction of various metal ions from nitric acid to n-dodecane

Sasaki, Yuji; Zhu, Z.-X.; Sugo, Yumi; Kimura, Takaumi

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10

The extraction of metals by N,N,N',N'-tetraoctyl-diglycolamide (TODGA) from nitric acid to n-dodecane was investigated. From the measurement of distribution ratios, it was obvious that Ca (ionic radius: 100pm), trivalent and tetravalent ions with ionic radii of 87-113 and 83-94 pm are highly extractable by TODGA. In order to evaluate the extraction capacity in extraction solvent using DGA compounds, we measured the limits of metal concentration (LOC) for Ca(II), Nd(III) and Zr(IV). For the purpose to enhance the LOC value, we examined the modifier of solvent, N,N-dihexyl-octanamide(DHOA) and DGA with longer alkyl chain. It is evident that LOC is increased with DHOA concentration and the length of alkyl chain attached to N atom of DGA.

Journal Articles

Radiolysis of TODGA and its effect on extraction of actinide ions

Sugo, Yumi; Sasaki, Yuji; Kimura, Takaumi; Sekine, Tsutomu*; Kudo, Hiroshi*

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10

no abstracts in English

69 (Records 1-20 displayed on this page)