Project/Area Number |
20K12211
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 64010:Environmental load and risk assessment-related
|
Research Institution | Meiji University |
Principal Investigator |
|
Co-Investigator(Kenkyū-buntansha) |
肴倉 宏史 国立研究開発法人国立環境研究所, 資源循環・廃棄物研究センター, 室長 (70331973)
|
Project Period (FY) |
2020-04-01 – 2023-03-31
|
Project Status |
Completed (Fiscal Year 2022)
|
Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2021: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
|
Keywords | 掘削岩 / 大気曝露 / 乾湿繰返し / 還元 / 表面変質 / 黄鉄鉱 / 炭酸化 / 重金属等 / 日光 / 温度 / ヒ素 / 変質 / 放出量 / 溶脱 |
Outline of Research at the Start |
ヒ素を含む掘削岩はトンネル工事等で大量に発生するため,周辺環境にヒ素が溶脱しないように対策し,再利活用が求められている.対策の設計には,掘削岩からのヒ素溶脱量の正確な評価が必要である.しかし,溶脱過程において大気曝露等によって岩表面が構造変質しヒ素形態が易溶化するため,正確にヒ素溶脱量が評価できていない.そこで本研究では,実現象に近い大気暴露と還元暴露を表現できる装置により暴露させた掘削岩の物理的・化学的な表面構造,ヒ素形態,ヒ素溶脱量を評価,ヒ素溶脱過程におけるヒ素形態の変化を岩表面の構造変質と関連付けながら解明し,ヒ素溶脱量を正確に評価できる曝露試験条件を提示する.
|
Outline of Final Research Achievements |
Appropriate evaluation of the amount of arsenic leached from excavated rock after reuse is necessary for the suitable reuse of the large amount of excavated rock generated by tunnel construction. This study aims to quantitatively clarify the relationship between the amount of change in arsenic phases associated with surface structural alteration and the drying-wetting cycles and reduction conditions of the excavated rock exposed after reuse. Under wetting-drying cycles, toxic metal(loid)s were released from pyrite with the oxidation of pyrite caused by fine granulation. The main factors that change the release of toxic metal(loid)s from pyrite would be the decrease in pH and the formation of amorphous and crystalline iron derived from the pyrite oxidation. Chemical and biological reduction increased the amount of As released, but the amount of increase was less than that under the drying-wetting cycles.
|
Academic Significance and Societal Importance of the Research Achievements |
建設工事で大量に発生する掘削岩は,処分場の残余容量が少ないため,環境に悪影響を与えないように再利用することが期待されている.本研究成果は,掘削岩を再利用する際に還元環境よりも乾湿を繰り返す大気暴露条件のほうが掘削岩からの重金属類の溶脱が高まる可能性を定量的に明らかにしたものである.
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