| Project/Area Number |
17K14731
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Hydraulic engineering
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| Research Institution | Hiroshima University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
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| Keywords | ヘドロ / 凝集・分散 / 吸着イオン / ゼータ電位 / 沈降速度 / 陽イオン交換 / 表面電位 / 有機物量 / イオン強度 / 巻き上がり / 凝集・分散機構 / 電気二重層 |
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| Outline of Final Research Achievements |
Mixing of fresh water with seawater increases ionic strength which is one of the parameters of electrostatic force. It causes increasing of settling velocity of sediment, because electric double layer become thin due to increasing of ionic strength. Electrostatic force is important factor to understand of flocculation and dispersion mechanism of sediment in estuary. In this study, adsorbed cation and ion concentration of pore water of sediment were replaced compulsively. We considered relationship between electrostatic force and settling velocity using zeta potential, quantity and type of adsorbed cation, and settling velocity of sediment.
The results revealed that the zeta potential changes under the influence of both the adsorbed cation and the ionic strength of the solution. It is possible to estimate the settling velocity including the effects of the ionic strength and the adsorbed ions.
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| Academic Significance and Societal Importance of the Research Achievements |
これまで粘土鉱物に対して吸着イオンを交換した場合の凝集性の変化について検討した研究例は存在したが，粘土鉱物に有機物が付着した複雑な特性を持つ有機泥を対象として電気化学的な効果を検討した研究は無かった．本研究では，有機泥に吸着するイオンの種類や量が凝集・分散力に与える影響をゼータ電位と関連付けて検討した．本研究においては，有機泥の凝集性は吸着イオンの量や種類，溶液のイオン強度によって変化することを明らかにした．さらに，ゼータ電位が吸着イオンと間隙水のイオン強度によって変化することから，ゼータ電位から簡易的に電気化学的な効果を推定できることを示した．
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