検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 14 件中 1件目~14件目を表示
  • 1

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

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

 被引用回数:0 パーセンタイル:13.21(Energy & Fuels)

Asse II salt mine, Germany, contains low and intermediate level radioactive waste that must be retrieved in the upcoming years. Potentially contaminated salts and brines will require treatment. $$^{137}$$Cs would be the main contaminant. Cs$$^{+}$$ is problematic to selectively recover due to its chemical similarity with Na$$^{+}$$ and K$$^{+}$$ which are present in high quantity in a salt mine. This paper is offering a solution for Cs$$^{+}$$ separation from concentrated chloride salt media by solvent extraction with calixarene-crown-ether extractants in alcoholic diluent.

論文

Marking actinides for separation; Resonance-enhanced multiphoton charge transfer in actinide complexes

松田 晶平; 横山 啓一; 矢板 毅; 小林 徹; 金田 結依; Simonnet, M.; 関口 哲弘; 本田 充紀; 下条 晃司郎; 土井 玲祐; et al.

Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05

 被引用回数:3 パーセンタイル:39.68(Multidisciplinary Sciences)

fブロック元素は化学的性質が類似している。一方、それらの電子スペクトルではf電子準位間の光学遷移が明瞭に異なる。このf-f遷移波長での共鳴励起によって元素の酸化状態を制御することができれば、化学的な分離が難しいfブロック元素の精密分離技術が生まれる可能性がある。これまでに3つのランタノイド元素で共鳴多光子還元が観測されているが、アクチノイドでの共鳴多光子反応は報告例はなかった。本研究では硝酸水溶液においてアクチノイドの一つである三価アメリシウムの共鳴多光子電荷移動による光酸化を観測した。また、硝酸錯体が一次過程に寄与することが示唆された。

論文

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

Simonnet, M.; 小林 徹; 下条 晃司郎; 横山 啓一; 矢板 毅

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

 被引用回数:8 パーセンタイル:87.47(Chemistry, Inorganic & Nuclear)

Phenanthroline carboxamide compounds are promising for lanthanide intra-series separation. This paper presents a study on the effect of structure modification of phenanthroline carboxamides onto the extraction of the whole lanthanide series. The study consists in theoretical calculations, extraction experiments of the 14 stable lanthanides and EXAFS analyses of Nd and Dy complexes. The comparison of the tridentate monocarboxamides and the tetradentate dicarboxamides shows different trend in the series extraction, although both preferentially extract the light lanthanides. The amide substituents, although not directly coordinating the metal ions, were also found to impact the distribution ratio, most probably due to a modification in the internal polarity of the molecules. This latter effect, if extrapolated to other nitrogen-based ligands such as pyridines or triazines, can be used to further fine-tune extractants for a process improvement.

論文

Lanthanide intra-series separation by a 1,10-phenanthroline derivative; Counterion effect

Simonnet, M.; 鈴木 伸一; 宮崎 有史*; 小林 徹; 横山 啓一; 矢板 毅

Solvent Extraction and Ion Exchange, 38(4), p.430 - 440, 2020/00

 被引用回数:15 パーセンタイル:71.68(Chemistry, Multidisciplinary)

Separation of lanthanides is especially challenging because of their chemical similarities. Therefore, improving the separation process is essential. In this work, we present the effect of the counterion nature on the lanthanide extraction by a 1,10-phenanthroline derivative, the $$N$$-octyl-$$N$$-tolyl-1,10-phenanthroline-2-carboxamide. Modification of the counterion yields a drastic change in selectivity, with a shift in the maximum of extraction from the light lanthanides (Pr, Nd, Sm) in nitrate system to the heavy lanthanides (Dy, Ho) in perchlorate system. Other salts (NaCl, NaNO$$_{2}$$) showed a gradual increase in extraction along the whole lanthanide series, or no effect (Na$$_{2}$$SO$$_{4}$$). The difference was explained by different coordination in the organic phase. The reversed behaviour depending on the anion is especially interesting because a cycling extraction/back-extraction of light lanthanides in nitrate/chloride media or a cycling extraction/back-extraction of heavy lanthanides in perchlorate/nitrate media can enhance the separation factors of respectively Nd and Dy/Ho.

論文

Thorium oxide dissolution in HNO$$_{3}$$-HF mixture; Kinetics and mechanism

Simonnet, M.; Barr$'e$, N.*; Drot, R.*; Le Naour, C.*; Sladkov, V.*; Delpech, S.*

Radiochimica Acta, 107(4), p.289 - 297, 2019/04

 被引用回数:2 パーセンタイル:22.31(Chemistry, Inorganic & Nuclear)

This paper is an attempt to find out thorium oxide dissolution mechanism in HNO$$_{3}$$-HF mixture. In a previous paper, several parameters effects on thorium oxide dissolution have been described, with specific focus on hydrofluoric acid effect, which can lead to an increase of the dissolution rate if present in small amount, but precipitates as ThF$$_{4}$$ at higher content. Based on this previous study, experimental data were fitted using several dissolution models in order to find out the best one. Finally, a revisited model based on literature and considering the ThF$$_{4}$$ formation was proposed. It describes the main steps of dissolution and is able to fit the experimental data for a wide range of solution compositions. This point is crucial since it allows considering an extrapolation of the established model to not-yet-studied conditions.

論文

Quantitative analysis of Cs extraction by some dialkoxycalix[4]arene-crown-6 extractants

Simonnet, M.; 宮崎 有史*; 鈴木 伸一; 矢板 毅

Solvent Extraction and Ion Exchange, 37(1), p.81 - 95, 2019/00

 被引用回数:4 パーセンタイル:18.42(Chemistry, Multidisciplinary)

Cesium extraction from acidic media by seven dialkoxy-calix[4]arene-crown-6 compounds in several diluents was studied. 2-Nonanone was found to be a suitable diluent for cesium extraction. Nitric acid concentration variation reveals a maximum distribution ratio, whose position depends on extractant and diluent. This maximum was explained quantitatively by a competitive extraction of H$$^{+}$$. An analytical mass-action extraction model accounting for activity effects is proposed that fits correctly the different datasets. The analysis showed a nitrate hyper-stoichiometry in alkyl ketone diluents. This effect yields efficient back-extraction at low acidity. Benzo substitution on the crown ether lowers nitric acid extraction, improves sodium separation, but also degrades potassium and rubidium separation.

論文

Cesium liquid-liquid extraction by calix-crown ethers; Solvent effect

Simonnet, M.; 宮崎 有史; 鈴木 伸一; 矢板 毅

Progress in Nuclear Science and Technology (Internet), 5, p.66 - 69, 2018/11

$$^{137}$$Cs is a dangerous fission product because of its half-life of 30 years and its high production yield. After several years, it becomes one of the main heat generator in nuclear waste; it would thus be beneficial to remove it before deep repository storage. Cesium also shows high mobility in the environment, thus being one of the most dangerous material released in accidental situation. Because the chemistry of cesium is close to these of sodium and potassium, found in great amount in water, cesium recovery requires very high separation factor towards these elements. Calix-crown-ether compounds show high extraction of Cs, and Na separation factor up to million (up to ten thousands for K), depending on experimental conditions and extractant structure. This study attempts to qualitatively and, when possible, quantitatively describe these dependencies. Focus has been made on HNO$$_{3}$$ concentration (0.01M to 6M), solvent nature, and extractant structure, based on the already well-documented di-octyloxy-calix[4]mono-crown-6.

口頭

Cesium extraction by calix-mono-crown-ethers; Extractant and solvent effects

Simonnet, M.; 宮崎 有史; 鈴木 伸一; 矢板 毅

no journal, , 

Study of cesium separation from acidic and alkaline waste has been conducted since the 90's. Calix[4]-crown-6-ethers can selectively extract cesium with higher distribution ratios than crown-ethers or dicarbollides. Several authors focused on dioctyloxycalix[4]crown-6 (DOC[4]C6), also tested on real waste in dodecane/TBP mixture. 99.9% of cesium was extracted but TBP, mandatory to solvate the calix-crown in dodecane, lowered the selectivity. The distribution ratio DCs remained also rather low. This study focuses on extractant and solvent effects. Because DOC[4]C6 showed good results and is well-documented, extractants were synthesized by modifying its structure: change of the alkoxy chain length led to didodecyloxycalix[4]crown-6 (DDC[4]C6) and diethylhexyloxycalix[4]crown-6 (DEHC[4]C6); change on the crown-ether led to dioctyloxycalix[4]benzo-crown-6 (DOC[4]BC6) and dioctyloxycalix[4]di-benzo-crown-6 (DOC[4]DBC6). Studies on DOC[4]BC6 and DOC[4]DBC6 can be found in literature. Based on literature study, pure solvents: n-octanol (n=1,2,3), methylcyclohexanone (MCHK), 2-nonanone; and mixtures of 1-octanol + 10% modifiers (nitrophenyloctylether (NPOE), TBP) have been tested.

口頭

Cesium separation from aqueous streams by calix-monocrown-arene

Simonnet, M.; 宮崎 有史*; 鈴木 伸一; 小林 徹; 土井 玲祐; 塩飽 秀啓; 矢板 毅

no journal, , 

$$^{137}$$Cs is one of the highest heat generators in nuclear waste. Removing it prior to deep geological disposal can thus help reducing the necessary volumes and costs of the final repository. This isotope is also one of the main contaminants that was released during the Fukushima Nuclear Power Plant accident. Liquid-liquid extraction can be a suitable method for decontamination. In this study, seven different extractants from the calix-mono-crown-arene family have been compared as respect to distribution ratio, separation factors and closer atoms distances to cesium. Distribution ratios also strongly depend on diluent nature. EXAFS study was thus conducted on two extractants in chloroform and 2-nonanone to investigate whether diluent nature can impact the cesium-ligand complex itself. Spectra showed that whilst no difference was observed on the first coordination shell, diluent nature impacted the second shell. However, oxygen positions remained similar in both diluents, leading to a probable change in benzene $$pi$$-electron interaction with cesium.

口頭

Extraction of cesium by calix-crown-ether

Simonnet, M.; 宮崎 有史*; 鈴木 伸一; 小林 徹; 矢板 毅

no journal, , 

Results on cesium extraction by calixarene crown-ether in several diluents are presented. An extraction mechanism was proposed, which correctly fits the different datasets. Found empirical equilibrium constants were correlated with diluent parameters for a better comparison. Afterwards, chloroform and 2-nonanone were compared on the obtained distribution ratios, separation factors and atomic scale differences. EXAFS studies proved that the modification of diluent yields a change in the local cesium environment.

口頭

1,10-phenanthroline carboxamide ligands for lanthanide separation; Diluent effect

Simonnet, M.; 小林 徹; 鈴木 伸一; 矢板 毅

no journal, , 

Efficient separation of rare-earth elements has recently been under a renewed interest. One of the most common elemental separation method is liquid-liquid extraction, for which the state of the art is wide due to the similarities with the studies on actinides separation from lanthanides. Therefore, many different extractants can be found in literature, among which 1,10-phenanthroline-based ligands have shown a strong ability for the extraction of trivalent elements. In this study, we focused on 1,10-phenanthroline carboxamide compounds, because they can selectively extract one lanthanide from the series, with the nature of this lanthanide dependent on the extractant structure. Some compounds were tested in different media, and it was found that the nature of the diluent and the composition of the aqueous feed also yield to a maximum shift among the lanthanide series. This study thus aims at emphasizing diluent effect on lanthanide extraction by 1,10-phenanthroline carboxamide ligands.

口頭

Cesium extraction by calixarenes crown-ether; Diluent effect

Simonnet, M.; 宮崎 有史*; 鈴木 伸一; 矢板 毅

no journal, , 

$$^{137}$$Cs is a troublesome fission product for both nuclear waste reprocessing and the cleaning of contaminated areas (Fukushima). Because Cs belongs to the alkali elements, it is hard to separate from Na and K, whose natural abundances are high. Calixarenes crown-ether were found to be efficient alkali extractants, with the alkali selectivity determined by the number of ether functions. It was found that ligands with 6 ether functions are optimum for cesium whilst 4 is optimum for Na, yielding great Na separation factors. However, the resulting high oxygen contents yields a low solubility in aliphatic diluents. Different diluents were thus used in literature, such as alcohols, ketones, chloroform, nitrophenylalkylether or dodecane with a modifier. Whilst the distribution ratios greatly varied along with the diluent, few studies focused on understanding this phenomenon. The aim of the present work is thus to study the diluent effect at both macroscopic (distribution ratio and separation factor comparison) and microscopic (EXAFS analysis) scales. For the latter study, two diluents, chloroform and 2-nonanone, were chosen. Their properties (density, viscosity, dielectric constant, water solubility) are all different, except from the calixarene crown-ether solubility which is high in both cases. Additional interactions between the diluent and the counterion were also investigated. The study focuses on acidic aqueous solutions only.

口頭

Feasibility study of a CHON-UNEX process

Simonnet, M.; Muller, L.*; Sittel, T.*; Wessling, P.*; Mullich, U.*; Geist, A.*

no journal, , 

Reaching a sustainable nuclear waste management is one of the major challenges to gain public acceptance. The most commonly accepted solution is to process the spent fuel to recover useful isotopes, along with removing the highest heat emitters. Several processes were designed to achieve the separation of the actinides to be potentially re-used as nuclear fuel, and of Sr and Cs to decrease the heat load of the final nuclear waste to be disposed of. Most of these processes consist in a step-by-step methodology, requiring the use of many stages, except for the UNEX process that aimed at co-extracting An(III), Ln(III), Cs(I) and Sr(II) from the PUREX raffinate. Unfortunately, none of the extractants are CHON-compatible, nor the diluent that is also toxic. The present study shows the feasibility of a CHON-UNEX process, where An(III), Ln(III), Cs(I) and Sr(II) are co-extracted and then selectively stripped, allowing to merge several processes into one.

口頭

Effect of the counterion on the selectivity of lanthanides by 1,10-phenanthroline carboxamide derivatives

Simonnet, M.; 小林 徹; 横山 啓一; 矢板 毅

no journal, , 

Lanthanides are especially difficult to separate from each other due to their similar chemical behavior. However, ensuring high elemental purity is necessary for most industrial applications. 1,10-phenanthroline carboxamide compounds showed good results towards selective lanthanide separation in nitric acid medium. Here, we report the change in selectivity that occurs when modifying the counterion.

14 件中 1件目~14件目を表示
  • 1