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Journal Articles

Determination of humic substances in deep groundwater from sedimentary formations by the carbon concentration-based DAX-8 resin isolation technique

Terashima, Motoki; Endo, Takashi*; Miyakawa, Kazuya

Journal of Nuclear Science and Technology, 57(4), p.380 - 387, 2020/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Characterization and thermodynamic study of humic acid in deep groundwater at Horonobe, Hokkaido, Japan

Kimuro, Shingo*; Kirishima, Akira*; Nagao, Seiya*; Saito, Takumi*; Amano, Yuki; Miyakawa, Kazuya; Akiyama, Daisuke*; Sato, Nobuaki*

Journal of Nuclear Science and Technology, 55(5), p.503 - 515, 2018/05

 Times Cited Count:3 Percentile:44.17(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Effects of weak organic acids on the size distribution and size-dependent metal binding of humic substances as studied by flow field-flow fractionation

Yamashita, Yuji*; Saito, Takumi

Journal of Environmental Chemical Engineering, 3(4), p.3024 - 3029, 2015/12

Humic substances are natural organic matters with heterogeneity in the size distribution and composition of there functional groups. In this study, the effects of organic acid, which are often used as pH buffering agents, on the size of a humic substance and size-dependent binding of metal ions on the humic substance were investigated by flow-field flow fractionation (Fl-FFF). Comparing the three organic acids, Tris, MES, and MOPS, the size of purified Aldrich humic acid (PAHA) changed in the presence of Tris and MES, suggesting that the interaction with these organic acid modulated the molecular structure of PAHA; on the other hand, MOPS hardly affect the size of PAHA. Size-dependent binding of europium (Eu$$^{3+}$$) and uranium (UO$$_{2}$$$$^{2+}$$) were also studied by Fl-FFF in the presence of MOPS. The binding of these metal ions were not homogeneous with respect to the size of PAHA; they exhibited high affinity to PAHA fractions with 5 nm hydrodynamic diameter.

Journal Articles

Physicochemical and ion-binding properties of highly aliphatic humic substances extracted from deep sedimentary groundwater

Saito, Takumi; Terashima, Motoki; Aoyagi, Noboru; Nagao, Seiya*; Fujitake, Nobuhide*; Onuki, Toshihiko

Environmental Science; Processes & Impacts, 17(8), p.1386 - 1395, 2015/08

 Times Cited Count:5 Percentile:74.36(Chemistry, Analytical)

The deep groundwater HSs were different from surface HSs, having high aliphaticities, sulfur contents, and small molecular sizes. The amounts of their acidic functional groups were comparable to or slightly larger than those of surface HSs; however, the magnitude of Cu$$^{2+}$$ binding to the deep groundwater HSs was smaller. The NICA-Donnan model attributed this to the binding of Cu$$^{2+}$$ to chemically homogeneous carboxylic-type sites via mono-dentate coordination at relatively low pH. The binding mode tended to shift to multi-dentate coordination with carboxylic-type and probably more heterogeneous alcoholic hydroxide-type groups at higher pH. This study shows the particularity of the deep groundwater HSs in terms of their physicochemical and ion-binding properties, compared with surface HSs.

Journal Articles

Extraction of groundwater humic substances and characterization by synthetic resin

Ueda, Masato; Sakamoto, Yoshiaki*

Genshiryoku Bakkuendo Kenkyu, 12(1-2), p.31 - 39, 2006/03

no abstracts in English

Journal Articles

Influence of humic substances on the $$^{63}$$Ni migration through crushed rock media

Tanaka, Tadao; Sakamoto, Yoshiaki; Mukai, Masayuki; Maeda, Toshikatsu; Nakayama, Shinichi

Radiochimica Acta, 92(9-11), p.725 - 729, 2004/12

 Times Cited Count:1 Percentile:89.36(Chemistry, Inorganic & Nuclear)

Migration experiments of $$^{63}$$Ni for crushed rocks, granite and tuff, were performed under the coexistent condition with a humic acid and a fulvic acid of 0-30 mg/l in concentration, which are Nordic humic substances supplied from International Humic Substance Society. Migration experiments of Ni had been performed by a column system, to investigate migration behavior of Ni through a column packed crushed rock. The Ni concentration in the effluent passed through the column was corresponding to the fractional percentage of Ni complexing with humic substance in influent solution. This result suggests that the Ni complexing with humic substance in influent solution was flowed out from the column without any effective interactions with the rock media. The migration behavior of Ni could be expressed by a migration model taking account of the complexation kinetics of Ni with humic substance in the aqueous phase.

Journal Articles

Migration models of neptunium and americium in groundwater under the present condition of humic substances

Tanaka, Tadao; Sakamoto, Yoshiaki; Sawada, Hiroshi; Ogawa, Hiromichi

JAERI-Conf 2003-010, p.134 - 141, 2003/09

We have performed migration experiments of Np(V) and Am(III) for crushed granite, under the coexistent condition with humic acid substance. As for Np, the periodical concentration changes in the breakthrough curve and the migration velocity of Np passed through the column were not affected by the coexistence of the humic substance. As for Am, on the other hand, the periodical concentration changes in the breakthrough curve were affected by the humic substance concentration. The migration behavior of Am passed through the present column system could be expressed by a migration model taking account of the non-equilibrium state.

Journal Articles

In situ ATR-FTIR spectroscopy for functional groups of humic substances complexing with metal ions

Tanaka, Tadao; Sakamoto, Yoshiaki; Ogawa, Hiromichi

Genshiryoku Bakkuendo Kenkyu, 9(1), p.29 - 34, 2002/09

To obtain structural information on functional groups of humic substances complexing with metal ions, infrared (IR) spectral analysis of the humic substances dissolving in aqueous solutions has been studied by ATR (Attenuated Total Reflection) method. By using the ATR method, IR spectral shifts of humic substance due to complexation with metal ions were observed. The observation provided with information on complexation kinetics, and on characteristics of functional groups depending on solvent properties, such as pH and solute concentrations. These information was difficult to be obtained by conventional FTIR spectroscopy using powdered humic substances. The obtained results show that IR spectral shifts on the functional groups of the humic substances complexed with metal ions could be possibly characterized ${it in situ}$ by using the ATR-FTIR spectroscopy.

Journal Articles

Form of radionuclides dissolved in river at an accidentally contaminated area

Matsunaga, Takeshi; Nagao, Seiya*; Takeda, Seiji; Ueno, Takashi; Amano, Hikaru

Dai-43-Kai Kankyo Hoshano Chosa Kenkyu Seika Rombun Shorokushu (Heisei-12-Nendo), p.49 - 50, 2002/03

no abstracts in English

Journal Articles

Degradation characteristics of humic acid during photo-Fenton processes

Fukushima, Masami*; Tatsumi, Kenji*; Nagao, Seiya

Environmental Science & Technology, 35(18), p.3683 - 3690, 2001/09

 Times Cited Count:120 Percentile:7.23(Engineering, Environmental)

no abstracts in English

Journal Articles

Reactivity between humic substances isolated from groundwater and metals by three-dimensional fluorescence spectrometry

Imanaka, Masayo*; Nagao, Seiya; Nakaguchi, Yuzuru*; Yamaguchi, Yoshitaka*; Suzuki, Yasuhiro*; Murakami, Masahiro*; Hiraki, Keizo*

Proceedings of International Conference on the Biogeochemistry of Trace Elements (ICOBTE2001), P. 662, 2001/00

no abstracts in English

Journal Articles

The Migration behavior of Np(V) in sandy soil and granite media in the pressence of humic substances

Sakamoto, Yoshiaki; Nagao, Seiya; Ogawa, Hiromichi; Rao, R. R.*

Radiochimica Acta, 88(9-11), p.651 - 656, 2000/09

 Times Cited Count:11 Percentile:37.98(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Characteristics of the fluorescent substances in the Yodo river system by three-dimensional excitation emission matrix spectroscopy

Suzuki, Yasuhiro*; Nakaguchi, Yuzuru*; Hiraki, Keizo*; Nagao, Seiya; *; *

Chikyu Kagaku, 32, p.21 - 30, 1998/00

no abstracts in English

Journal Articles

Direct measurement of fluorescence characteristics of aquatic humic substances by three-dimensional fluorescence spectrophotometer

Nagao, Seiya; Suzuki, Yasuhiro*; Nakaguchi, Yuzuru*; ; Hiraki, Keizo*

Bunseki Kagaku, 46(5), p.335 - 342, 1997/00

no abstracts in English

Journal Articles

Speciation of Cs,Sr and transuranic elements in natural organic substances of surface soil layers

Amano, Hikaru; Watanabe, Miki*; Onuma, Yoshikazu*; Ueno, Takashi; Matsunaga, Takeshi; N.D.Kuchma*

The Role of Humic Substances in the Ecosystems and in Environmental Protection, 0, p.709 - 716, 1997/00

no abstracts in English

Journal Articles

5 years research project between RIAP and JAERI on secondary migration of radionuclides in terrestrial and aquatic environment; Some preliminary results

Amano, Hikaru; Matsunaga, Takeshi; Ueno, Takashi; Onuma, Yoshikazu*; Watanabe, Miki*; Yanase, Nobuyuki; Nagao, Seiya; Sukhoruchkin, A. K.*

Proceedings of 5th International Scientific and Technical Conference on the Problems of Liquidation of Chernobyl Accident Consequences, P. 74, 1996/00

no abstracts in English

Journal Articles

Influene of coexistent humic acid on adsorption and migration behavior of $$^{85}$$Sr in a coastal sand

Tanaka, Tadao; Mukai, Masayuki;

Hoshasei Haikibutsu Kenkyu, 1(2), p.169 - 176, 1995/05

no abstracts in English

Oral presentation

Electrochemical study on the redox properties of humic substances from deep sedimentary groundwater

Saito, Takumi; Terashima, Motoki; Onuki, Toshihiko

no journal, , 

Redox properties of humic substances extracted from deep sedimentary groundwater was investigated by cyclic voltammetry and bulk electrolysis with a mediator organic molecule. Reversible current-potential curves were observed with the mediator, although electrode reaction of humic substances are slow in general. The redox capacities of various humic substances exhibited positive correlation with their aromaticity; those of deep groundwater humic substances were appreciably smaller than those of surface humic substances.

Oral presentation

Characteristics of dissolved organic matter in deep aquifer of sedimentary area

Ito, Yuki*; Oyama, Takahiro*; Miyakawa, Kazuya; Sasamoto, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Effects of microbial activity and coexisting cation on association of selenium with humic substance in deep groundwater

Terashima, Motoki; Amano, Yuki

no journal, , 

Effects of microbial activity and coexisting cations on association of selenium (Se) with humic substance (HS) in deep groundwater were investigated by means of incubation experiments, DAX-8 extraction, and size-exclusion chromatography combined with UV-Vis and ICP-MS detections (SEC-ICP-MS). Selenite added into the groundwater was effectively reduced to elemental Se(0) by microbial activity stimulated by a nutrient. The DAX-8 extraction showed the existence of Se fraction that is extracted with HS. The SEC-ICP-MS analysis for alkaline extracts of the DAX-8 showed that the chromatogram of Se, HS and Fe are well corresponded each other, and were obtained regardless of the sterilization of groundwater. These indicate the possibility that Se can associate with HS in deep groundwater via the interaction with Fe.

23 (Records 1-20 displayed on this page)