Neutron imaging of generated water inside polymer electrolyte fuel cell using newly-developed gas diffusion layer with gas flow channels during power generation

Nasu, Mitsunori*; Yanai, Hiroshi*; Hirayama, Naoki*; Adachi, Hironori*; Kakizawa, Yu*; Shirase, Yuto*; Nishiyama, Hiromichi*; Kawamoto, Teppei*; Inukai, Junji*; Shinohara, Takenao; et al.

Journal of Power Sources, 530, p.231251_1 - 231251_11, 2022/05

https://doi.org/10.1016/j.jpowsour.2022.231251

Synergistic enhancement of the extraction and separation efficiencies of lanthanoid(III) ions by the formation of charged adducts in an ionic liquid

Okamura, Hiroyuki; Mizuno, Masayoshi*; Hirayama, Naoki*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*

Industrial & Engineering Chemistry Research, 59(1), p.329 - 340, 2020/01

https://doi.org/10.1021/acs.iecr.9b04998

The synergistic ionic-liquid extraction and extraction equilibrium of lanthanoid(III) (Ln(III)) ions have been investigated using 2-thenoyltrifluoroacetone (Htta) and trioctylphosphine oxide (TOPO) in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TfN]). The selective synergistic effect for heavier Ln(III) ions was found using a combination of Htta and TOPO in [Cmim][TfN], leading to enhanced separability among Ln(III) ions. The extracted Ln(III) species and the extraction constants in the Htta-TOPO system were determined by three-dimensional extraction equilibrium analysis. The selective synergism for heavier Ln(III) ions in the Htta-TOPO system was ascribed to the formation of hydrophobic, charged adducts, such as Ln(tta)(TOPO) and Ln(tta)(TOPO), in [Cmim][TfN].

Overview of JENDL-4.0/HE and benchmark calculations

Kunieda, Satoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Minato, Futoshi; Okamoto, Tsutomu; Sato, Tatsuhiko; Nakashima, Hiroshi; Iwamoto, Yosuke; Iwamoto, Hiroki; Kitatani, Fumito; et al.

JAEA-Conf 2016-004, p.41 - 46, 2016/09

https://doi.org/10.11484/jaea-conf-2016-004

Neutron- and proton-induced cross-section data are required in a wide energy range beyond 20 MeV, for the design of accelerator applications. New evaluations are performed with recent knowledge in the optical and pre-equilibrium model calculations. We also evaluated cross-sections for p+Li and p+Be which have been highly requested from a medical field. The present high-energy nuclear data library, JENDL-4.0/HE, includes evaluated cross-sections for incident neutrons and protons up to 200 MeV (for about 130 nuclei). We overview substantial features of the library, i.e., (1) systematic evaluation with CCONE code, (2) challenges for evaluations of light nuclei and (3) inheritance of JENDL-4.0 and JENDL/HE-2007. In this talk, we also focus on the results of benchmark calculation for neutronics to show performance of the present library.

Laser-induced fluorescence and infrared spectroscopic studies on the specific solvation of tris(1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato)europium(III) in an ionic liquid

Okamura, Hiroyuki; Sakae, Hiroki*; Kidani, Keiji*; Hirayama, Naoki*; Aoyagi, Noboru; Saito, Takumi*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*

Polyhedron, 31(1), p.748 - 753, 2012/01

https://doi.org/10.1016/j.poly.2011.10.031

Cooperative intramolecular interaction of diazacrown ether bearing -diketone fragments on an ionic liquid extraction system

Shimojo, Kojiro; Okamura, Hiroyuki; Hirayama, Naoki*; Umetani, Shigeo*; Imura, Hisanori*; Naganawa, Hirochika

Dalton Transactions, 2009(25), p.4850 - 4852, 2009/07

A novel extractant -diketone-substituted diaza-18-crown-6 demonstrated very efficient extraction of Sr due to an intramolecular synergistic effect on the ionic liquid extraction system and recovery of Sr from the ionic liquid was successfully achieved under acidic conditions.

Spectroscopic studies on cadmium complexes in an ionic liquid

Okamura, Hiroyuki; Shimojo, Kojiro; Hirayama, Naoki*; Imura, Hisanori*; Naganawa, Hirochika

no journal, , 

no abstracts in English

Intramolecular synergistic effect on ionic liquid extraction system with crownn ether bearing -diketone fragments

Shimojo, Kojiro; Okamura, Hiroyuki; Ikeda, Atsushi; Saito, Takumi*; Hirayama, Naoki*; Umetani, Shigeo*; Imura, Hisanori*; Naganawa, Hirochika

no journal, , 

no abstracts in English

Structure analysis of complex extracted into an ionic liquid with X-ray absorption spectroscopy

Okamura, Hiroyuki; Shimojo, Kojiro; Ikeda, Atsushi; Hirayama, Naoki*; Umetani, Shigeo*; Imura, Hisanori*; Naganawa, Hirochika

no journal, , 

no abstracts in English

Effect of chelating agent on ionic liquid chelate extraction of trivalent metals using bidentate ligands

Eguchi, Ayano; Morita, Kotaro*; Okamura, Hiroyuki; Hirayama, Naoki*

no journal, , 

In chelate extraction of metal ions into organic solvents, formation of their uncharged complexes with ligands is required. Moreover, coordinatively saturated (unhydrated) complexes are more preferable as extracted species. On the other hand, in ionic liquid chelate extraction, ionic liquid can extract charged species and coordinatively unsaturated (hydrated) species. In this study, the effects of bidentate ligands on ionic liquid chelate extraction of trivalent metal ions, Fe(III), Al(III), Ga(III) and In(III), into 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imides ([Cmim][TfN], n=2,4,8) was studied using 8-quinolinol (HQ) and 2-mercaptopyridine -oxide (HSPyO) as extractants. The extraction selectivity order for trivalent metal ions was Fe Ga In Al for HQ and Fe In Ga Al for HSPyO. Namely, HSPyO was favorable for extraction of In(III). The extractability of Ga(III) was in the order of [Cmim][TfN] [Cmim][TfN] [Cmim][TfN] chloroform for HSPyO, whereas reversed order was obtained for HQ. These results were seemed to be based on difference in concentration of deprotonated bidentate ligands in water.

Synergistic ionic-liquid extraction for the selective separation of lanthanoids(III)

Okamura, Hiroyuki; Mizuno, Masayoshi*; Hirayama, Naoki*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*

no journal, , 

Ionic liquids have been widely investigated as novel functional extraction media in solvent extraction. We have investigated the synergistic ionic-liquid extraction of lanthanoids(III) (Ln(III)), and revealed that the synergistic effect is effective for the selective separation of Ln(III). In this study, the synergistic ionic-liquid extraction of Ln(III) with 2-thenoyltrifluoroacetone and trioctylphosphine oxide in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was investigated to evaluate the synergistic effect. In the ionic liquid system, the synergistic effect on selective extraction for heavier Ln(III) was observed in contrast to the conventional organic solvent systems. The slope analysis indicated that the neutral adduct and the cationic ternary complexes are extracted. The adduct formation constant of the cationic ternary complex increased with an increase in the atomic number. These results indicate that the formation of hydrophobic charged ternary complexes is a main factor for the selective synergistic effect toward heavier Ln(III).