Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-hexaoctyl nitrilotriacetamide (HONTA) using mixer-settler extractors in a hot cellBan, 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：15 Percentile：52.81(Chemistry, Multidisciplinary)A continuous counter-current experiment to separate minor actinides (MAs: Am and Cm) was performed with -hexaochyl nitrilotriacetamide (HONTA) as an extractant. Nitric acid of 0.08 M (mol/dm
) 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 
99% by optimizing separation conditions.
Sasaki, Yuji; Morita, Keisuke; Shimazaki, Shoma*; Tsubata, Yasuhiro; Ozawa, Masaki*
Solvent Extraction Research and Development, Japan, 23(2), p.161 - 174, 2016/05
We examined the masking effects of 16 water-miscible reagents, on the extraction of Mo, Re, Ru, and Pd. The extractants, methylimino-dioctylacetamide (MIDOA) and hexaoctyl-nitrilotriacetamide (NTAamide(C8)), show significantly high distribution ratios for these metals, were employed in this study. Masking effects were observed as a decrease of distribution ratio with an increase of masking agent concentration in these extraction systems. The results showed that Pd and Ru can be masked by similar reagents including N- or S- donor atoms, which suppressed the extraction into the organic phase. In contrast, distribution ratio of Mo was only slightly masked by the above mentioned reagents. The masking of Mo was achieved using complexing agents having a central N(CH
C(P)=O) framework that is important for this purpose. A masking agent for Re was not found in this study.
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.
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.
Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Morita, Keisuke; Suzuki, Tomoya; Shimazaki, Shoma; Ozawa, Masaki*
no journal, ,
no abstracts in English
Shimazaki, Shoma; Sasaki, Yuji; Tsubata, Yasuhiro; Morita, Keisuke; Suzuki, Tomoya; Ozawa, Masaki*
no journal, ,
no abstracts in English
Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Shimazaki, Shoma*
no journal, ,
no abstracts in English
Kaneko, Masashi; Watanabe, Masayuki; Matsumura, Tatsuro
no journal, ,
In Japan Atomic Energy Agency, the extraction reagents for the inter- and intragroup separation of mainor-actinides from lanthanides have been developed in order to construct the partitioning and transmutation process. We aim to reveal the separation mechanism using various extraction materials at a molecular level and to design the novel extraction reagents. In this study, we apply density functional calculations to the separation behavior of Am(III) from Eu(III) by DGA and NTA ligands. All metal compounds were modeled by referring the literatures. As the result, DGA ligand selectively coordinates to Eu(III) than Am(III), on the other hand, NTA ligand preferably coordinates to Am(III) than Eu(III), being consistent with the experimental selectivity.
Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency has been studying partitioning and transmutation systems. In this partitioning process, new extractants with highly practical and high extraction ability for minor actinoids was developed. New extractants, called NTAamide, were tested for mutual separation of trivalent minor actinoids and trivalent rare earth elements. Among the four NTAamides, hexaoctylnitrilotriacetamide (HONTA) provided the largest distribution ratio of trivalent americium, and was chosen. A continuous liquid-liquid extraction test was conducted using a multistage countercurrent mixer-settler extractor with HONTA. In this test, separation of MA(III) and RE(III) was achieved with very high yield.
Sano, Yuichi; Arai, Tsuyoshi*; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Kunii, Shigeru*
no journal, ,
JAEA has developed a hybrid process combining solvent extraction and low pressure loss extraction chromatography to achieve a reasonable MA(III) recovery process having superior safety and economy. In the solvent extraction, MA(III) is recovered with Ln(III) using inexpensive TBP extractants and centrifugal contactors having superior phase separation performance. In the extraction chromatography, MA(III) is separated from Ln(III) using specially designed adsorbents for low pressure loss. In this report, the outline of R&D program will be introduced.
Nagase, Midori*; Arai, Tsuyoshi*; Sano, Yuichi; Watanabe, So; Kunii, Shigeru*
no journal, ,
As a separation technology for recovering MA (III) from high-level radioactive liquid waste, we focused on an adsorbent impregnated with an NTA amide extractant. In this study, we synthesized H2EH NTA extractant, which is one of the NTA amide extractants, and investigated the adsorption / elution behavior for rare earth elements.
Sano, Yuichi; Arai, Tsuyoshi*; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Kunii, Shigeru*
no journal, ,
We have been developing a hybrid process combining solvent extraction and low pressure loss extraction chromatography for recovering trivalent minor actinides (MA(III): Am, Cm), which will decrease the waste and have good safety and economic performances. In this presentation, the outline of R&D program and some recent results will be introduced.
Yoshida, Masaaki*; Nemoto, Shuhei*; Nagase, Midori*; Arai, Tsuyoshi*; Emori, Tatsuya; Morita, Keisuke; Ban, Yasutoshi; Watanabe, So; Sano, Yuichi; Kunii, Shigeru*
no journal, ,
In this study, we investigated the adsorption characteristics of simulated nuclides of adsorbents carrying various NTA amide extracts. From the results of this test, It has become clear that HONTA-impregnated adsorbent showed a high adsorption distribution coefficient with respect to Ln (III) at a nitric acid concentration of 10
- 10
M. It has also revealed that all elements quickly reached adsorption equilibrium. In addition, the elution of the extractant and Sty / DVB was not occurred from the results of the extractant elution test from the impregnated adsorbent. We discuss the applicability of the extraction chromatography method using various NTA adsorbents.
Tsuchiya, Tatsumi*; Okada, Makoto*; Watanabe, So; Sano, Yuichi; Arai, Tsuyoshi*; Matsuura, Haruaki*
no journal, ,
For any adsorbent including an adsorbent using a silica carrier granulated by the freeze dried method, the adsorbed species has almost the same structure as the solvent extraction system, and the coordination structure changes with the nitrate concentration is related with the tendency of adsorption rate with nitrate concentration.
Kuzure, Yoshiaki*; Miyagawa, Akihisa*; Nagatomo, Shigenori*; Nakatani, Kiyoharu*; Yoshida, Masaaki*; Nemoto, Shuhei*; Arai, Tsuyoshi*; Ambai, Hiromu; Hasegawa, Kenta; Sano, Yuichi
no journal, ,
Concentration dependencies of nitric acid, nitrate ion, and so on for the adsorption and elution rates (mass transfer coefficients) of FP (Ln) in silica adsorbent, carrying various NTAamide extractants, were measured in the single silica particle/solution system by fluorescence microspectroscopy. The adsorption and elution rates were improved by changing polymercoating conditions for the silica adsorbent granulated by the freeze-drying method. We will discuss the mass transfer coefficients influenced by the nitric acid and nitrate ionconcentrations.
Tsuchiya, Tatsumi*; Okada, Makoto*; Watanabe, So; Sano, Yuichi; Arai, Tsuyoshi*; Matsuura, Haruaki*
no journal, ,
Structural analysis was performed by EXAFS measurement on samples in which lanthanide (Ln (III)) was adsorbed on an adsorbent impregnated with various NTA amide extracts. The adsorption behavior of NTA amide adsorbents with different side chains suggested that the distance to oxygen around an element changes due to the difference in side chains.
Sasaki, Yuji
no journal, ,
Since initially reported TODGA extractant at 2001, I have developed four analogous extractants, which have O, S, and N donor at ether position. The distribution ratios of over 70 metals using these extractants were obtained in order to know the all-inclusive extractability. Concerning with this, I developed water-soluble reagents with the same central frame but with short alkyl chains and examined their masking effects.
Miyazaki, Yasunori; Sano, Yuichi; Takeuchi, Masayuki; Hoshino, Masamitsu*; Gejo, Tatsuo*; Adachi, Junichi*
no journal, ,
no abstracts in English
Kinoshita, Ryoma; Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*
no journal, ,
Many metal ions are stable in hydrochloric acid solutions as anionic species; diamidic-extractants containing tertiary amino nitrogen atom, such as NTAamide (hexaalkyl-nitrilotriacetamide), are normally protonated in acidic solutions and become cationic extractants. In this study, the ion-pair extraction reactions of metal chloride anions with cationic NTAamide(C6) extractant were investigated. In addition, we attempted to predict the distribution ratio by combining the stability constants of metal chloride complexes and DFT calculations, and compared the results with experimental values.
Miyazaki, Yasunori; Hoshino, Masamitsu*; Gejo, Tatsuo*; Adachi, Junichi*; Takahashi, Osamu*
no journal, ,
-hexaoctylnitrilotriacetamide (HONTA) is one of the extractants that form complexation with minor actinides (Am
, for example). The initial reaction of radiolysis, whether it is direct or indirect, is ionization of HONTA after interaction with electrons. In this study, VUV and soft X-ray were irradiated to HONTA on the gold plate, and the released electrons were energy analyzed and detected by SCIENTA to acquire the photoelectron spectra. The quantum chemical calculations were performed to evaluate the electronic structure and ionization energy of HONTA. For future works, these results will be applied to the molecular dynamics simulation in order to elucidate radiolysis.
Suzuki, Hideya*; Nakamura, Satoshi; Emori, Tatsuya; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Ban, Yasutoshi
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning and transmutation systems (P&T). In P&T, JAEA proposed a novel hydrometallurgical process called "SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process". In the SELECT process, HexaOctyl NitriloTriacetAmide (HONTA) with six 
-octyl side chains is used for the mutual separation of minor actinides (MA) and rare earth elements (RE). In the present study, extraction tests were carried out with HONTA and three nitrilotriacetamides (NTA amides) with different side chains. The results show that the different side chains of NTA amides affect the extraction behaviors of MA and RE.
