Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ueda, Yuki; Kobayashi, Toru; Nakamura, Satoshi; Ban, Yasutoshi; Kaneta, Yui; Nabatame, Nozomi; Micheau, C.; Tokunaga, Kohei; Nakabe, Rintaro; Kaneko, Masashi*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)Understanding the structural factors governing the metal ions selectivity of solvent extraction systems is crucial for developing advanced processes for partitioning and transmutation of high-level radioactive waste. Here, we systematically investigated the effect of alkyl side-chain branching in nitrilotriacetamide (NTAamide) extractants on the extraction of lanthanum (La) and neodymium (Nd), chosen as representative lanthanides. Four extractants having each eight carbon atoms as one of the amide chains with identical molecular weights but different degrees of alkyl branching were examined. Distribution ratios were measured as a function of HNO
concentration, and the local coordination structures of La and Nd were analyzed by extended X-ray absorption fine structure (EXAFS), while supramolecular aggregation in the organic phase was characterized by small-angle neutron scattering (SANS). EXAFS analysis revealed that the inner-sphere coordination environment of La and Nd was essentially unaffected by the degree of alkyl branching. In contrast, SANS results showed that extractants with fewer branched alkyl groups formed larger aggregates at low HNO concentrations, particularly in the case of Nd, where aggregation was found to facilitate extraction and prevent precipitation of poorly soluble complexes. These findings demonstrate that alkyl branching strongly influences supramolecular aggregation, which in turn governs extraction behavior. This work highlights the potential of nanoscale structural control as a new design concept for improving selectivity in lanthanide and actinide solvent extraction systems.
Kaneta, Yui; Kobayashi, Toru; Tsuji, Takuya; Honda, Mitsunori; Yokoyama, Keiichi; Mampuku, Yuzo*; Yaita, Tsuyoshi*
Clays and Clay Minerals, 73, p.e26_1 - e26_8, 2025/04
Times Cited Count：1 Percentile：50.74(Chemistry, Physical)The desorption behavior of stable Cs adsorbed onto weathered biotite (WB), a clay mineral abundant in Fukushima soils, was investigated using a mechanochemical (MC) method that combines physical grinding by ball impact with a wet process promoting chemical reactions. The results, oxalic acid desorbed Cs to some extent without significantly affecting the layered structure of the clay minerals; ammonium chloride, showed an exfoliation of the layer structure, resulting in a stable desorption of Cs independent of samples. Regarding the real soil samples collected in Fukushima, the MC method using ammonium chloride solution desorbed 80% of 
Cs. In contrast, oxalic acid did not always result in radioactive Cs made sufficiently desorbed for all the samples. Based on these findings, the MC method with ammonium chloride effectively promotes radioactive Cs desorption from interlayers due to synergistic effects from the layered structure's exfoliation and chemical interaction.
Honda, Mitsunori; Kaneta, Yui; Muraguchi, Masakazu*; Hayakawa, Kosetsu*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Goto, Takuya*
AIP Advances (Internet), 14(5), p.055034_1 - 055034_6, 2024/05
Times Cited Count：5 Percentile：56.05(Nanoscience & Nanotechnology)This study examines the utilization of Fukushima weathered biotite(WB)as an alternative to conventional thermoelectric materials traditionally derived from rare and toxic substances. WB underwent milling, classification, and subsequent heat treatment via molten-salt treatment to produce crystals exhibiting conductivity akin to semiconductors within from 650
C to 850C range. Evaluation of WB and the derived crystal's electrical conductivity and Seebeck coefficient showcased their viability for high-temperature thermoelectric applications. Consequently, WB attained a dimensionless figure of merit (ZT) of 0.015, signaling its potential as a thermoelectric material that surpasses 650C.
Honda, Mitsunori; Kaneta, Yui; Yaita, Tsuyoshi
AIP Advances (Internet), 13(1), p.015314_1 - 015314_6, 2023/01
Times Cited Count：5 Percentile：39.75(Nanoscience & Nanotechnology)The efficiency of the sorption of Sr
on weathered biotite, a type of clay minerals was investigated. Removal of Sr and Cs
is important in the treatment of contaminated water from the 1F accident, which is one of the radionuclide waste treatment problems. We focused on developing an adsorption method for Sr ions using weathered biotite, which are abundant in Fukushima. Applying a molten salt treatment, the amount of sorbed Sr simply increased as the added mass ratio of strontium chloride (SrCl
) increased from 1:1, 1:5, and 1:10 for the one-fold, five-fold, and ten-fold additions of SrCl, respectively. Then, the crystal structure of weathered biotite as an adsorbent was evaluated by X-ray diffraction (XRD) analysis. Thus, it was observed that the WB retained its original crystal structure even after the sorption of Sr. Extended X-ray absorption fine structure (EXAFS) analysis was performed to investigate the local sorption structure of Sr in the WB. The results revealed that Sr was preferentially sorbed into the SiO
and AlO layers when Sr was in the low mass ratio, while, it was mainly sorbed into the SiO layer when the ratio was high.
molecular dynamics simulations reveal the hydration structure of the radium(II) ionYamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08
Times Cited Count：19 Percentile：63.32(Multidisciplinary Sciences)no abstracts in English
Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.
Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05
Times Cited Count：12 Percentile：46.25(Multidisciplinary Sciences)no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
Hosha Kagaku, (45), p.28 - 30, 2022/03
no abstracts in English
Haraga, Tomoko; Hishinuma, Yukio*; Kaneta, Yui*; Ishimori, Kenichiro; Takahashi, Kuniaki
no journal, ,
no abstracts in English
Kaneta, Yui; Yokoyama, Keiichi; Yaita, Tsuyoshi
no journal, ,
no abstracts in English
Honda, Mitsunori; Goto, Takuya*; Kaneta, Yui; Yaita, Tsuyoshi
no journal, ,
We have been investigating the restoration of the environment in Fukushima. One of the issues to be solved is the removal of cesium from the soil of Fukushima. As we studied the technology to remove cesium from the soil of Fukushima, we thought that the reclamation could be accelerated by adding new functions (e.g., thermoelectric properties) to the clay minerals after removal. Soil clay minerals are composed of Si, Al, Fe, etc., and are low environmental load materials. Soil clay minerals were reduced by molten salt electrochemistry and their properties were investigated. Thermal diffusivity measurements showed no temperature dependence in the untreated sample, while the temperature dependence was significantly different in the case of -1.4 V molten salt electrolysis treatment.
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Okumura, Masahiko; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; et al.
no journal, ,
no abstracts in English
Honda, Mitsunori; Kaneta, Yui; Muraguchi, Masakazu*; Hayakawa, Kosetsu*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Goto, Takuya*; Yaita, Tsuyoshi
no journal, ,
Ten years have passed since the earthquake and nuclear power plant accident at 1F that occurred in 2011, and the contaminated soil generated in Fukushima Prefecture is now being managed as removed soil at intermediate storage facilities. In the course of developing technology to remove cesium from the removed soil, we have focused on the functionality of crystalline minerals after removal of cesium, and have been investigating their potential as thermoelectric materials. In this study, we report on the evaluation of thermoelectric properties (electrical conductivity, thermal diffusivity, and Seebeck coefficient) and structural analysis of crystalline minerals.
Honda, Mitsunori; Kaneta, Yui; Muraguchi, Masakazu*; Hayakawa, Kosetsu*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Goto, Takuya*; Yaita, Tsuyoshi
no journal, ,
Twelve years have passed since the 1F accident that occurred in 2011, and contaminated soil generated in Fukushima Prefecture is being managed as removed soil. We have focused on the functionality of several crystalline minerals obtained in the process of developing a technology to remove Cs from the removed soil, and are examining their potential as thermoelectric conversion materials. In this study, we report on the evaluation of thermoelectric properties (electrical conductivity, thermal diffusivity, and Seebeck coefficient) of the crystalline minerals.
Honda, Mitsunori; Kaneta, Yui; Hayakawa, Kosetsu*; Muraguchi, Masakazu*; Iino, Chiaki*; Oda, Masato*; Ishii, Hiroyuki*; Goto, Takuya*; Yaita, Tsuyoshi
no journal, ,
In this study, thermoelectric properties (electrical conductivity, Seebeck coefficient, and thermal diffusivity) were evaluated (OZMA-1-S1) for polycrystalline minerals obtained by systematically changing the conditions of WB and the molten treatment. The Seebeck coefficient and thermal diffusivity were evaluated on the same sample. Macroscopic and microscopic structures were identified by various X-ray analyses and first-principles calculations. As for the electrical conductivity results of WB, the biotite material is usually known as an electrical insulator at room temperature, but after grinding, classification, molten salt treatment, and sintering, it was found to have electrical conductivity on the order of 1.49 
10
(
V/K) in the temperature range 650-850C, indicating that it has semiconducting electrical conductivity properties. Seebeck coefficient measurements in the same temperature range showed a high value of -2.010
(V/K). Calculating the dimensionless performance index 
from the obtained results, =0.29 was obtained. Regarding the thermoelectric property evaluation results for the molten salt treated polycrystalline minerals, higher electrical conductivity properties than WB were obtained for the same temperature range. These results suggest that WB can be used to show useful thermoelectric properties in the high temperature region above 650C.
Amamoto, Ippei; Kobayashi, Hidekazu; Ayame, Yasuo; Hasegawa, Yoshio*; Utsumi, Kazuo*; Takeshita, Kenji*; Inaba, Yusuke*; Onoe, Jun*; Koshizaka, Akiko*; Kaneta, Yui*
no journal, ,
no abstracts in English
Honda, Mitsunori; Kaneta, Yui; Yaita, Tsuyoshi
no journal, ,
no abstracts in English
Kaneta, Yui*; Suzuki, Shinichi; Yaita, Tsuyoshi
no journal, ,
no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Okumura, Masahiko; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; et al.
no journal, ,
no abstracts in English
Kaneta, Yui; Kobayashi, Toru; Matsumura, Daiju; Tsuji, Takuya; Honda, Mitsunori; Yokoyama, Keiichi; Yaita, Tsuyoshi
no journal, ,
no abstracts in English
Honda, Mitsunori; Kaneta, Yui; Muraguchi, Masakazu*; Hayakawa, Kosetsu*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Goto, Takuya*; Yaita, Tsuyoshi
no journal, ,
Ten years have passed since the Great East Japan Earthquake and the accident at the Fukushima Daiichi Nuclear Power Plant, and the contaminated soil generated in Fukushima Prefecture has been decontaminated and managed as removal soil. We have been conducting research on the volume reduction and recycling of Fukushima weathered biotite, which is known to be a strong adsorbent of radioactive Cs contained in the removed soil. In this study, thermoelectric properties (Seebeck coefficient, electrical conductivity, and thermal diffusivity) of soil clay minerals and molten salt-electrolyzed soil clay minerals were evaluated in order to clarify their properties as thermoelectric materials.
