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Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Shiwaku, Hideaki; Yaita, Tsuyoshi
RSC Advances (Internet), 13(25), p.17001 - 17007, 2023/06
Times Cited Count：1 Percentile：39.98(Chemistry, Multidisciplinary)no abstracts in English
Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi
Analytical Sciences, 33(11), p.1305 - 1309, 2017/11
Times Cited Count：11 Percentile：40.1(Chemistry, Analytical)Maeda, Motoki*; Narita, Hirokazu*; Tokoro, Chiharu*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi
Separation and Purification Technology, 177, p.176 - 181, 2017/04
Times Cited Count：22 Percentile：59.58(Engineering, Chemical)Masunaga, Kosuke; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
In Ningyo-toge Environmental Engineering Center, water level of mill tailings pond is planned to be lowered to reduce overflow risks caused by heavy rain etc., as a part of remediation activities of the Uranium Mine. It is known that the concentration of Fe and As and other elements in the mine drainage are decreased by retaining in the pond. The aims of this study are to reduce the load of water treatment facility and to determine the efficient countermeasure method for remediation of the mill tailings pond. To accomplish these, purification mechanisms of Fe and As in the pond were investigated, referring other studies. Chemical composition of water drainage in the pond was estimated by the chemical equilibrium analysis with advection using PHREEQC. The result of the simulation was almost reproducible for Fe. For As, it was reproducible when taking into account of surface complexation to ferrihydrite in sediment in the bottom of the pond.
Kawasaki, Yohei*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
Arsenic in mine wastewater is an important issue in environmental research. In this study, to better understand the phenomena involved in the removal of arsenic from wastewater, the dynamic behavior of arsenic in the Yotsugi Mill Tailings Pond at Ningyo-toge mine was investigated. By utilizing geosphere fluid modeling software (GETFLOWS), we first reproduced the overall area flow through the advection-dispersion of non-reactive silicate ion with assuming the groundwater inlet. Following this, the total concentrations of arsenic and iron were reproduced by including in the previous advection-dispersion model, the first order kinetics for oxidation of As(III) and Fe(II) along with the precipitation equilibrium of Fe(III) as ferrihydrite. Finally, the adsorption of As(V) or As(III) on ferrihydrite was included in the simulation by considering the surface complexation model previously validated in batch adsorption tests. The results highlighted the natural oxidation of Fe(II) to Fe(III) and the subsequent precipitation of Fe(III) as ferrihydrite. Furthermore, the as-precipitated ferrihydride exhibited a strong ability to remove the arsenic by adsorption. The results also emphasized that the oxidation of As(III) to As(V) and the competitive adsorption between arsenic and the natural phosphates in water, play a key role in the natural removal of the arsenic in the pond.
Kawasaki, Yohei*; Fukuta, Hiroki*; Yagisawa, Makoto*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
no abstracts in English
Kawasaki, Yohei*; Yagisawa, Makoto*; Fukuta, Hiroki*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
Kawasaki, Yohei*; Yagisawa, Makoto*; Fukuta, Hiroki*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
no abstracts in English
Kawasaki, Yohei*; Yagisawa, Makoto*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
no abstracts in English
Kawasaki, Yohei*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki
no journal, ,
Tawara, Yasuhiro*; Yoshida, Takafumi*; Matsuura, Taichi*; Fukazawa, Soki*; Tokoro, Chiharu*; Fukushima, Shigeru; Ohara, Yoshiyuki
no journal, ,
no abstracts in English
