Selective removal of radiocesium from micaceous clay for post-accident soil decontamination by temperature-controlled Mg-leaching in a column

Yin, X.; Zhang, L.*; Meng, C.*; Inaba, Yusuke*; Wang, X.*; Nitta, Ayako; Koma, Yoshikazu; Takeshita, Kenji*

Journal of Hazardous Materials, 387, p.121677_1 - 121677_10, 2020/04

https://doi.org/10.1016/j.jhazmat.2019.121677

Sorption properties of aluminum hexacyanoferrate for platinum group elements

Mishima, Ria; Inaba, Yusuke*; Tachioka, Sotaro*; Harigai, Miki*; Watanabe, Shinta*; Onoe, Jun*; Nakase, Masahiko*; Matsumura, Tatsuro; Takeshita, Kenji*

Chemistry Letters, 49(1), p.83 - 86, 2020/01

https://doi.org/10.1246/cl.190741

Separation of platinum group metals (PGMs) from high-level liquid waste generated from the reprocessing of spent nuclear fuels is important to produce good quality vitrified glass for final disposal. A new sorbent, Aluminum hexacyanoferrate (AlHCF), was synthesized and the general sorption behavior of PGMs from concentrated nitric acid was examined. Nitric acid caused substantial elution of AlHCF but the sorption of Pd stabilized the structure. Consequently, Rh was sorbed in the presence of Pd, whereas single Rh sorption caused complete dissolution of AlHCF. Relation between sorbed mount of Pd vs eluted Al and Fe revealed that the elution ratio of Al and Fe was not the same as molar ratio of synthesized AlHCF, indicating the re-sorption of Fe resulted in formation of new structure. The sorption mechanism of PGMs by this new sorbent, AlHCF, not only the simple ion exchange, but also oxidation reduction reaction as well as kinetics play important rule. Understanding the general sorption and dissolution behavior will help improve the sorption performance of PGMs by AlHCF.

Recovery of minor actinides from spent fuel via an extraction chromatographic technique using TPPEN-immobilized gels

Koyama, Shinichi; Suto, Mitsuo; Obayashi, Hiroshi; Takeshita, Kenji*; Ogata, Takeshi*; Oaki, Hiroshi*; Inaba, Yusuke*

Separation Science and Technology, 47(14-15), p.2024 - 2028, 2012/11

https://doi.org/10.1080/01496395.2012.707268

A series of separation experiments was performed to study the recovery process for minor actinides (MAs) from the actual spent fuel by using an extraction chromatographic technique. TPPEN gel was used as a new extraction chromatographic agent. Mixed oxide fuel was used as a reference spent fuel to demonstrate the recovery of the MAs. The MOX fuel, including 29.9 wt% plutonium (Pu), was irradiated up to 119 GWd/MTM, and the fuel was then prepared for the extraction experiment. A Mixed solution of MAs and lanthanides (Lns) was prepared. The TPPEN gel was immersed in a 0.01 M NaNO solution, and the pH was adjusted to 4.0. Next, an extraction column was prepared using the TPPEN gel, and the mixed solution of MAs and Lns was passed through the column. The Lns were detected in the eluent after washing with 0.01 M NaNO (pH 4.0). For detecting the MAs, the pH of the eluent was changed to 2.0.

Am/Eu separation with a new ligand, N,N,N',N'-tetrakis((4-butoxypyridin-2-yl)methyl)ethylenediamine (TBPEN), a hydrophobic derivative of TPEN

Matsumura, Tatsuro; Inaba, Yusuke*; Mori, Atsunori*; Takeshita, Kenji*

Journal of Nuclear Science and Technology, 47(2), p.123 - 126, 2010/02

https://doi.org/10.3327/jnst.47.123

We are developing a new MA/Ln separation process with TPEN and its derivatives for P&T technology. TPEN is a hexadentate soft-donor ligand that has six soft-donor sites as a kind of podand type molecule and can encapsulate a metal ion. TPEN has good selectivity of Am(III) from Ln(III) and has potential to establish partitioning of MA. From the viewpoint of practical application, the hydrophobicity of TPEN must be improved. Because the dissolution of a slight amount of TPEN (about 10 mol/l) to water will restrict decontamination of Ln in extraction process. In this study, the hydrophobicity of TPEN was improved by introducing alkyl groups and the effect of the introduction of alkyl groups on the separation of Am(III) and Eu(III) was examined. One of them, N,N,N',N'-tetrakis((5-butoxypyridin-2-yl)-methyl)ethylenediamine, TBPEN, showed good selectivity and the maximum separation factor, SF, was 91 at pH 3.02. The hydrophobicity of TBPEN is checked by the distribution data between water and chloroform, and improved successfully. The approach for development of hydrophobic derivatives of TPEN was effective.

AM(III)/EU(III) separation with hydrophobic alkylated TPEN

Matsumura, Tatsuro; Takeshita, Kenji*; Inaba, Yusuke*; Mori, Atsunori*

Proceedings of 10th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation (CD-ROM), 6 Pages, 2010/00

http://www.oecd-nea.org/science/reports/2010/actinide10th-poster-docs/III.pdf#pages=156

no abstracts in English

Am(III)/Eu(III) separation with hydrophobic derivatives of TPEN

Matsumura, Tatsuro; Inaba, Yusuke*; Takeshita, Kenji*; Mori, Atsunori*

Proceedings of International Solvent Extraction Conference "Solvent Extraction-Fundamentals to Industrial Applications" (ISEC 2008), 4 Pages, 2008/09

We are developing a new MA/Ln separation process with derivatives of TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine) for P&T technology. TPEN has good selectivity of Am(III) from Ln(III). However, TPEN is soluble slightly (about 10 mol/l) to water. In this study, the hydrophobicity of TPEN is improved by introducing alkyl groups and the selectivity of Am(III) and Eu(III) is examined. We succeeded to synthesize several new hydrophobic derivative of TPEN. One of the ligands, TDdPEN (N,N,N',N'-tetrakis((5-dodecyloxypyridin-2-yl)-methyl)ethylenediamine) showed high selectivity. The maximum separation factor, SF, was over 800. Hydrophobic derivatives of TPEN that have potential of application to the MA/Ln separation process was synthesized successfully.

Synthesis of TPEN derivatives bearing polymerizable functional groups

Fukuoka, Sachio*; Inaba, Yusuke*; Nakajima, Yasutaka*; Mori, Atsunori*; Takeshita, Kenji*; Matsumura, Tatsuro; Nakano, Yoshio*

no journal, , 

no abstracts in English

Am(III)/Eu(III) separation with N,N,N',N'-tetrakis((5-alkoxypyridin-2-yl)methyl)ethylenediamine, Hydrophobic Derivatives of TPEN

Matsumura, Tatsuro; Inaba, Yusuke*; Takeshita, Kenji*; Mori, Atsunori*

no journal, , 

no abstracts in English

Development of extraction chromatographic agents based on nitrogen-donor ligand for the separation of actinide

Ogata, Takeshi*; Takeshita, Kenji*; Oaki, Hiroshi*; Inaba, Yusuke*; Mori, Atsunori*; Matsumura, Tatsuro; Nakano, Yoshio*

no journal, , 

N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) is one of the podand-type ligands with six nitrogen-donors and recognize the slight difference in the softness between Am(III) and Eu(III). We have tried to synthesize a novel extraction chromatographic agent, which exploit such feature of TPEN. The use of the polymer gel as a support of the extractant can be expect to suppress the elution of the extractant and keep the flexibility of extractant. N,N,N',N'-tetrakis-(4-propenyloxy-2-pyridylmethyl)ethylenediamine (TPPEN) which is TPEN analog introducing polymerizable group to pyridine ring was used as a cross-linker of N-isopropylacrylamide (NIPA). Furthermore, the TPPEN-NIPA gel on highly porous silica was prepared to improve the mechanical strength of the gel. These extraction chromatographic agents have been tested for the separation of Am(III) and Eu(III). Characterization and extraction performance of the extraction chromatographic agents will be described.

Separation behavior of Am(III) from lanthanide(III) by TPEN-NIPA Gel and the separation mechanism study

Suzuki, Shinichi; Akutsu, Kazuhiro; Yaita, Tsuyoshi; Okamoto, Yoshihiro; Ogata, Tsuyoshi*; Takeshita, Kenji*; Inaba, Yusuke*; Ikeda, Atsushi; Kobayashi, Toru; Oaki, Hiroshi*; et al.

no journal, , 

no abstracts in English