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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：18 パーセンタイル：69.88(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 
-octyl--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
) showed a gradual increase in extraction along the whole lanthanide series, or no effect (NaSO
). 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.
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：5 パーセンタイル：17.71(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.
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
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
concentration (0.01M to 6M), solvent nature, and extractant structure, based on the already well-documented di-octyloxy-calix[4]mono-crown-6.
豊森 佑夏*; 辻 悟*; 光田 紫乃布*; 岡山 陽一*; 芦田 汐未*; 森 敦紀*; 小林 徹; 宮崎 有史; 矢板 毅; 荒江 祥永*; et al.
Bulletin of the Chemical Society of Japan, 89(12), p.1480 - 1486, 2016/09
被引用回数：8 パーセンタイル：29.47(Chemistry, Multidisciplinary)Preparation of 2,2'-bithiophene derivatives bearing 
-alkenyl groups at the 3,3'-positions and ring-closing metathesis reactions of the obtained compound were performed. The reaction of bithiophene bearing 3-butenyl substituents with 5mol% Grubbs 1st generation catalyst underwent ring-closing metathesis (RCM) to afford the cyclized product 7 showing winding vine-shaped molecular asymmetry in up to 88% yield. Enantioselective RCM was also achieved by the use of chiral Schrock Hoveyda molybdenum-alkylidene catalyst in up to 87% ee.
Awual, M. R.; 宮崎 有史; 田口 富嗣; 塩飽 秀啓; 矢板 毅
Chemical Engineering Journal, 291, p.128 - 137, 2016/05
被引用回数：228 パーセンタイル：99.33(Engineering, Environmental)A novel macrocyclic ligand of di-o-benzo-p-xylyl-28-crown-8-ether (DOBPX28C8) was prepared and successfully anchored onto the mesoporous silica for the fabrication of mesoporous hybrid adsorbent (MHA) using direct immobilization approach and serving as an efficient adsorbent for Cs removal. The high amount of K (7.69 mM) was slightly affected the Cs adsorption because the hydration radius of K is close to the Cs than that of the other cation of Na. Also the Cs adsorption efficiency was more higher even in the presence of 1,025 fold K and 1,739 fold Na, respectively. The functional group of DOBPX28C8 ligand embedded onto the mesoporous silica exhibited more conformational freedom, and the benzene ring in para position was consolidated for pai-electron orientation with expanding the ring size of DOBPX28C8 for easy capturing with high selectivity and adsorption ability towards the Cs.
Awual, M. R.; 矢板 毅; 宮崎 有史; 松村 大樹; 塩飽 秀啓; 田口 富嗣
Scientific Reports (Internet), 6, p.19937_1 - 19937_10, 2016/01
被引用回数：182 パーセンタイル：97.55(Multidisciplinary Sciences)A novel macrocyclic ligand of 
-benzo-
-xylyl-22-crown-6-ether (OBPX22C6) was developed and successfully immobilized onto mesoporous silica for the preparation of hybrid adsorbent. The benzene ring 
electron is the part of crown ether of OBPX22C6 for easy orientation of the macrocyclic compound for making the electron donation with Cs complexation. The results clarified that the Cs removal process was rapid and reached saturation within a short time. Considering the effect of competitive ions, sodium did not markedly affect the Cs adsorption whereas potassium was slightly affected due to the similar ionic radii. Due to its high selectivity and reusability, significant volume reduction is expected as this promising hybrid adsorbent is used for Cs removal in Fukushima wastewater.
松村 大樹; 小林 徹; 宮崎 有史; 岡島 由佳*; 西畑 保雄; 矢板 毅
Clay Science, 18(4), p.99 - 105, 2014/12
Real-time-resolved observation by using X-ray absorption fine structure spectroscopy was employed in order to study the interaction between dropped water and a mixture of clay minerals and cesium chloride. Change of X-ray absorption spectra were used for the evaluation of amount and chemical state of cesium compounds. For sericite and illite clays, relatively long lifetime of hydrated cesium ions was observed before adsorption on clay minerals. On the other hand, for vermiculite, kaolinite and zeolite clays, hydrated cesium ions were not intensely observed due to short reaction time between hydrated cesium ions and the clay minerals. The electronic configuration of cesium adsorbed on the vermiculite clay is different from that of cesium adsorbed on the other clay minerals. Real-time-resolved X-ray absorption fine structure spectroscopy observation is expected to be widely used for the study of the cesium adsorption on many clay minerals.
Awual, M. R.; 小林 徹; 塩飽 秀啓; 宮崎 有史; 元川 竜平; 鈴木 伸一; 岡本 芳浩; 矢板 毅
Chemical Engineering Journal, 225, p.558 - 566, 2013/06
被引用回数：196 パーセンタイル：98.69(Engineering, Environmental)This study was investigated the trace lanthanide (Nd(III), Eu(III) and Yb(III)) sorption and recovery from wastewater streams by novel hybrid adsorbent. The experiments were investigated to determine the effects pH, ions selectivity and lanthanide ions coordination by XAFS spectra. The EXAFS data revealed that O and N donor atoms of the HA were strongly coordinated to lanthanide ions to form stable complexes. However, the bond distance of O donor atoms was shorter than N donor atoms.
Awual, M. R.; 小林 徹; 宮崎 有史; 元川 竜平; 塩飽 秀啓; 鈴木 伸一; 岡本 芳浩; 矢板 毅
Journal of Hazardous Materials, 252-253, p.313 - 320, 2013/05
被引用回数：183 パーセンタイル：97.66(Engineering, Environmental)The oxygen and nitrogen donor atoms containing Lewis base N-methyl-N-phenyl-1,10-phenanthroline-2-carboxamide (MePhPTA) ligand was synthesized and subsequently an adsorbent was prepared by direct immobilization onto mesoporous silica. The crystallography for the Sm-MePhPTA complex suggested that MePhPTA was strongly coordinated to Sm(III) with oxygen and nitrogen by forming a stable complex with two 5-membered rings. The data clarified that bond lengths between Sm(III) and amide oxygen (2.475 
) were shorter than Sm-N (2.662 ) in phenanthroline moiety indicating strong oxygen driven adsorbent.
矢板 毅; 塩飽 秀啓; 鈴木 伸一; 小林 徹; 宮崎 有史; 元川 竜平; 岡本 芳浩
no journal, ,
福島第一原子力発電所の事故に伴い放出された放射性セシウムは、その周辺地域において深刻な環境汚染をもたらしている。そこでわれわれのグループでは使用済み吸着材の焼却廃棄を考慮した高分子吸着剤として、新規クラウンエーテルDB20C6の設計を実施し、開発に成功した。SPring-8を利用した放射光EXAFSに基づく構造解析によれば、DB20C6は、2.8付近の水など酸素ドナー原子との相互作用に加え、3.5前後の領域に供与に基づく相互作用が確認された。この相互作用は、DFT理論に基づく分子軌道計算によれば、DB20C6のベンゼン環からCsの空のd, f軌道に対する電子供与に基づくものであることがわかり、これがNa, K等の軽アルカリ金属からのCsの高い選択性を生み出している原因であることがわかった。中性子小角散乱実験では、DB20C6は、クラウン環がベンドすることによりCsに対し包接的に相互作用することなども併せて明らかとなった。DB20C6をシリカゲル基材に固定した吸着材を、福島県飯舘村での農業用水に対する除染試験に用いたところ、ほぼ100%のCs除染が可能であることが確認できた。
宮崎 有史; 鈴木 伸一; 小林 徹; Awual, M. R.; 塩飽 秀啓; 岡本 芳浩; 矢板 毅
no journal, ,
クラウンエーテル類は、エーテル鎖が形成する環サイズに対応したアルカリ金属イオンを選択的に認識することができる。本研究ではサイズ認識に加えて電子-セシウム相互作用に注目した新規クラウンエーテルの分子設計を行い、その合成と機能評価を行った。
Awual, M. R.; 小林 徹; 宮崎 有史; 元川 竜平; 塩飽 秀啓; 鈴木 伸一; 岡本 芳浩; 矢板 毅
no journal, ,
Complexation of lanthanide by solid state adsorbent is a very useful tool for separation, and extraction of Tm(III), Yb(III) and Lu(III) ions, if utilized in systems involving solid-liquid phases. In such cases, the selective complexation of lanthanide ions is a valuable characteristic for efficient operations. The O donor ligand preparation, characterization, mesoporous material processing, surface characterization, sequester lanthanides, Tm(III), Yb(III) and Lu(III) sorption experiments and complexation bonding mechanism will be discussed.
塩飽 秀啓; 矢板 毅; 鈴木 伸一; 小林 徹; 宮崎 有史; Awual, M. R.; 元川 竜平; 岡本 芳浩; 松村 大樹; 吉井 賢資; et al.
no journal, ,
東京電力福島第一原子力発電所の事故に伴い、放射性セシウムが環境中に放出され深刻な環境汚染を引き起こしている。そこで、我々は福島の土壌成分の中で特にセシウム吸着性の高いバーミキュライトに着目し、放射光を利用してCs脱離機構解明と脱離法の開発研究を行った。セシウムと直接結合している酸素には2種類存在することが分かった。その一つがやや共有結合性を帯びており、セシウムが脱離しにくい要因となっていると考えられる。また、DXAFS測定からほぐれた粘土端面からセシウムが拡散進入し粘土層間が閉じることによって安定化することが分かった。さらに粘土鉱物をシュウ酸で高温処理してセシウムの脱離過程を調べたところ、一部の粘土骨格が壊れるものの共有結合性の高い結合性分が最後まで残留することも分かった。粘土鉱物へのセシウムの吸着状態が極めて安定であることが明らかとなった。これまでの成果をSTXM結果やDFT計算結果と合わせて紹介する。
松村 大樹; 小林 徹; 宮崎 有史; Awual, M. R.; 鈴木 伸一; 岡島 由佳*; 西畑 保雄; 矢板 毅
no journal, ,
福島第一原子力発電所の事故に伴い、核燃料分裂生成物である放射性物質が環境中に漏洩した。中でも、比較的融点の低いセシウムは多量に放出され、周辺地域に重篤な環境汚染を引き起こしている。現在、除染のための多くの事業が展開され、本研究グループでは土壌中に取り込まれたCsを対象とした研究事業に参画している。Csは、土壌中の、特に粘土鉱物(層状珪酸塩)の層間に入り込むことで、不可逆的に吸着されることが指摘されている。本実験では、代表的な粘土鉱物(層状珪酸塩)に対して、Csの吸着(取り込み)過程を時分割X線吸収分光(XAFS)測定により動的に追跡した。結果、水和Csイオンは何らかの中間状態を経た後にVermiculiteの層間に取り込まれることが示された。また、層間隔は生成直後はやや長い距離を取り、取り込みに伴いわずかに収縮される結果が得られた。これは、Csを取り込む際にVermiculiteの層が短時間で口を閉じることを表している。
塩飽 秀啓; 矢板 毅; 鈴木 伸一; 小林 徹; 宮崎 有史; Awual, M. R.; 元川 竜平; 岡本 芳浩; 松村 大樹
no journal, ,
東京電力福島第一原子力発電所の事故に伴い、放射性セシウムが環境中に放出され深刻な環境汚染を引き起こしている。そこで、我々は福島の土壌成分の中で特にセシウム吸着性の高いバーミキュライトに着目し、放射光QXAFS測定法を利用してCs脱離機構解明と脱離法の開発研究を行った。その結果、少なくとも共有結合性とイオン結合性の性質を持つ2種類の酸素がセシウムと直接結合していることが分かった。セシウムが粘土鉱物から脱離しにくい要因となっていると考えられ、粘土鉱物へのセシウムの吸着状態が極めて安定であることが明らかとなった。また、セシウムを選択的に補足できる有機配位子系吸着剤の開発も行っており、吸着性能と置換基効果や、セシウム周囲の構造についてもQXAFS測定の結果と合わせて紹介する。
松村 大樹; 小林 徹; 宮崎 有史; 鈴木 伸一; Awual, M. R.; 岡島 由佳*; 西畑 保雄; 矢板 毅
no journal, ,
Dispersive XAFS technique is unique approach for the real-time-resolved observation of chemical reaction. X rays with wide-band energy are created by a curved crystal and counted by a space-resolved detector after sample transmission. We can obtain XAFS spectra without any mechanical motion of crystal or detector. We have developed dispersive XAFS observation system at BL14B1 (Japan Atomic Energy Agency beamline) of SPring-8 and applied to some chemical reactions. Complexation reactions of U and other ions are targets of our interest. 1-10 Hz EXAFS observation for the complexation reaction reveals that fast electronic change of center atoms and slow local structural change due to complex formation.
宮崎 有史; 小林 徹; 鈴木 伸一; 塩飽 秀啓; Awual, M. R.; 岡本 芳浩; 元川 竜平; 矢板 毅
no journal, ,
We have developed crown ether derivative compounds for cesium separation, and furthermore studied the relationship between structure and complexation ability for Cs. In this present study, the developed benzo-crown ethers were simple structures, but relatively high Cs selectivity than K was observed. The DFT calculation result suggested that electron donation from aromatic ring would also enhance Cs selectivity and we are re-considering the model for Cs selectivity. The other coordination properties of these crown ether derivatives with Cs were studied by NMR, UV-Vis spectroscopy and so on, and will be presented in this talk.
Awual, M. R.; 小林 徹; 塩飽 秀啓; 宮崎 有史; 元川 竜平; 鈴木 伸一; 岡本 芳浩; 矢板 毅
no journal, ,
A novel separation material for lanthanide was designed using O and N donor ligand immobilized mesoporous silica. The specific lanthanide transportation based on solution pH, sorption capacity, and recovery by stripping agents was performed. The interaction mechanism and lanthanide coordination after adsorption of specific Ln
at the solid interface have been studied by EXAFS. The proposed materials possessed sufficient loading and releasing capacities for specific lanthanide in repeated processes after sorption-recovery operations. The successful development of potential materials can serve as promising applications and time- and cost-effective tool for selective lanthanide sorption and recovery in separation technologies on an industrial scale.
Awual, M. R.; 小林 徹; 宮崎 有史; 塩飽 秀啓; 鈴木 伸一; 岡本 芳浩; 矢板 毅
no journal, ,
The O and N donor containing ligand was synthesized and then successfully immobilized onto mesoporous silica (hybrid materials) by a direct and building-block approach for lanthanide (Ln) separation. The coordination chemistry of Ln with O and N donor ligands has advanced because steric factors can be optimized with ligand set Ln contraction by choosing the best metal size from Ln. Also a new class macrocyclic ligand of AcDB20C6 was developed and DB24C8 and AcDB20C6 were directly immobilized onto mesoporous silica for Cs containing wastewater treatment. The AcDB20C6 has an ability to identify the Cs ion size based on cation and pai interaction. The pai electron of the benzene ring in AcDB20C6 and DB24C8 has high tendency to interact with d and f hybrid orbital electron of Cs. Moreover, the d and f hybrid orbital is absent in Na and K ions.
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.
