Bimodal pore size evolution of metakaolin-based geopolymers at the initial stage of curing; A Small-angle neutron scattering study

Toda, Kanako*; Motokawa, Ryuhei; Saito, Takumi*

Journal of Physical Chemistry C, 11 Pages, 2025/08

https://doi.org/10.1021/acs.jpcc.5c02876

Sorption of Cs and Eu onto coherent and melange-type pre-neogene sedimentary rocks

Hou, L.*; Toda, Kanako*; Mei, H.; Aoyagi, Noboru; Saito, Takumi*

Journal of Nuclear Science and Technology, 61(11), p.1488 - 1498, 2024/11

https://doi.org/10.1080/00223131.2024.2356767

Microbial effects on dissolved organic matters in deep groundwater

Sato, Hayato*; Toda, Kanako*; Beppu, Hikari*; Amano, Yuki; Saito, Takumi*

no journal, , 

no abstracts in English

Molecular characterization of reactive deep underground dissolved organic matters for metal ion using high-resolution mass spectrometry

Sato, Hayato*; Toda, Kanako*; Beppu, Hikari*; Amano, Yuki; Miyakawa, Kazuya; Saito, Takumi*

no journal, , 

no abstracts in English

Influence of heterogeneity on ions and HDO diffusion in pre-Neogene sedimentary rocks

Hou, L.*; Okamoto, Shunichi*; Toda, Kanako*; Fukatsu, Yuta; Ishidera, Takamitsu; Saito, Takumi*

no journal, , 

Evaluation of the interaction between deep groundwater natural organic matter and metal ions using fluorescence spectroscopy and multivariate analysis and arrangement of their origins

Nishi, Shusaku*; Miyakawa, Kazuya; Toda, Kanako*; Saito, Takumi*

no journal, , 

In HLW disposal, NOM changes radionuclides behavior. For surface NOM, models that express bonding with metal ions under various conditions have been proposed. To use such models in the safety evaluation of geological disposal, binding reactions between NOM in deep underground and nuclides are evaluated, and features are compared with the NOM in surface. In March 2021, we focused on the fact that NOM fluorescence is extinguished by combining with metal ions, and conducted quenching experiments where europium was added to the deep groundwater containing NOM. Using PARAFAC, a multivariate analysis method, fluorescent NOM components that contribute to binding are identified, and properties and reactivity with europium are discussed. In this presentation, new samples are added for more comprehensive discussions.

Molecular characterization and ion binding properties of deep underground dissolved organic matters using fluorescence spectroscopy and high-resolution mass spectrometry

Sato, Hayato*; Toda, Kanako*; Beppu, Hikari*; Eguchi, Ayano; Amano, Yuki; Miyakawa, Kazuya; Saito, Takumi*

no journal, , 

Evaluation of labile Cs in Fukushima rivers by diffusive gradients in thin films (DGT), 3; Relations between geochemical parameters

Tanaka, Takuro*; Saito, Takumi*; Toda, Kanako*; Fujiwara, Kenso; Terashima, Motoki; Nakanishi, Takahiro; Kobayashi, Natsuko*; Tanoi, Keitaro*; Kato, Hiroaki*

no journal, , 

Cs dispersed by the Fukushima Daiichi Nuclear Power Plant accident deposited in Fukushima area, that are not decontaminated in mountainous areas, may migrate through river water to animals and plants. Most of Cs in river are fixed in clay minerals, but there are some Cs that can be easily desorbed, named as labile components. It has been suggested that labile components affect the bioavailability of Cs. In this study, the labile Cs was sampled in situ from upstream to downstream in several rivers of Fukushima using a passive sampler called diffusive gradients in thin films (DGT). The desorption behavior of the labile component and factors affecting it will be discussed by examining the relationship with particulate Cs and geochemical parameters in river water.