| Project/Area Number |
15510024
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental impact assessment/Environmental policy
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| Research Institution | Niigata University |
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Principal Investigator |
AOYAMA Kiyomichi Niigata University, The Research Institute for Hazards in Snowy Areas, Professor, 積雪地域災害研究センター, 教授 (50018488)
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| Co-Investigator(Kenkyū-buntansha) |
TAGUCHI Yoji Niigata University, Faculty of Engineering, Professor, 工学部, 教授 (90018490)
KANO Naoki Niigata University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00272857)
YAMAMOTO Masashi Niigata University, Faculty of Agriculture, Professor, 農学部, 教授 (30018543)
NAKATA Makoto Niigata University, Graduate School of Science and Technology, Associate Professor, 大学院・自然科学研究科, 助教授 (80217744)
MIYAUCHI Shinosuke Nagaoka University of Technology, Professor, 工学部, 教授 (90018672)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | acid snow (rain) / pH / adsorption on ice surface / sulfate, phosphate, ammonium ions / Langmuir adsorption isotherm / pH of soils / acidified soils / dissolved elements / 酸性雪 / 酸性雨 / 吸着 / 硫酸イオン / 硝酸イオン / 不純物 / ザラメ雪 |
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| Research Abstract |
1)Acidic anions might be preferentially eluted first from the packed granular snow in the snowmelt season. The ions were transferred to a lower layer from the upper layer due to snowmelt or rain in early spring, and a portion of the melted water containing a large amount of ions is eluted first. In order to enhance the elution of sulfate ions from ice, spheres formed of sulfate-containing water were examined, and melting experiments were performed. The results of the melting experiment using a column showed higher concentrations of sulfate ions in the effluent drained first and lower concentrations in the later effluent. When using the solvent for melting experiment, the distribution of sulfate in an ice sphere was found with a biased curve.
2)The adsorption phenomena of phosphate or ammonium ions on the surface of ice crystals were experimentally examined. The amounts adsorbed immediately after the establishment of a quasi-equilibrium state obeyed a Langmuir adsorption isotherm. Therefore, it was suggested that the adsorption phenomena of the impurities on the ice surface caused the biased distribution and should probably be a significant factor in freeze separations.
3)The pH of the rain and snow falling in Niigata Prefecture has been found to be 4.6 on average. Most of the rain and snow in this area is considered ‘acidic, it must have an effect on the area s soils. In this study, the present state of soils gathered from mainly Niigata Prefecture was examined by the measurement of pH and the chemical analysis of dissolved elements from the soils. As a result of the experimental study, it was found that soil had become slightly acidified, and aluminum and manganese ions dissolve only slightly out of non-acidified soils, while they dissolve easily out of acidified soils.
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