physicochemical properties of hazardous elements in thermally treated contaminated soils

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K12216
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64020:Environmental load reduction and remediation-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Hashimoto Yohey 東京農工大学, (連合)農学研究科(研究院), 准教授 (80436899)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 土壌汚染

Outline of Final Research Achievements

The mechanism of lead leaching and volatilization from soil due to heat treatment was examined with a primary focus on chemical species using a model compound (ferrihydrite) and actual contaminated soils. The chemical form of lead adsorbed on ferrihydrite, an Fe hydroxide present in soil, showed a change at around 300oC to lead oxide (PbO) Using a contaminated soil containing lead, thermal treatments from 100 to 900oC were applied to clarify the solubility and chemical form of lead. At a treatment temperature of 900oC, the proportion of dissolved lead was found to be about 90% lower than that of the untreated soil. At high heat treatment temperatures of 900oC, aluminosilicates in the soil melted and lead was incorporated to form insoluble compounds.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

鉛を含む土壌を900oCで処理すると、鉛の溶出が未処理土壌と比較して90%程度低下することが分かった。熱処理温度が900oCの高温になると、土壌のアルミナケイ酸塩鉱物が融解し、鉛が取り込まれて不溶性の化合物を形成することも確認された。現状では主として水銀に適用されている土壌汚染の熱処理対策は、条件によっては鉛にも適用できる可能性があること、ならびに他の重金属類の処理においても研究を進めることによって汎用性が拡張できる可能性が示された。