Development of a system for capturing and recovering metal resources in groundwater using calcium carbonate method ground improvement technolo

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02246
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Wakayama National College of Technology
• Principal Investigator: Hayashi Kazuyuki 和歌山工業高等専門学校, 環境都市工学科, 教授 (30587853)
• Co-Investigator(Kenkyū-buntansha): 角田 範義 豊橋技術科学大学, 工学(系)研究科(研究院), 理事・副学長 (30201411) ; 岡村 未対 愛媛大学, 理工学研究科(工学系), 教授 (50251624) ; 安原 英明 愛媛大学, 理工学研究科(工学系), 教授 (70432797)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 透過性地中壁 / 地下水浄化 / 重金属 / 炭酸カルシウム / 地盤改良

Outline of Final Research Achievements

It was found that calcium carbonate crystals have a sufficient heavy metal capture function to reduce the concentration of heavy metal ions such as nickel, cobalt, manganese, lead, and zinc in aqueous solution to a level that reduces the concentration of heavy metals in solution to about 5% or less of the initial concentration. The decrease in the concentration of heavy metal ions in solution was almost equal to the increase in the concentration of the same divalent calcium ions, suggesting that the capture of heavy metals was due to ion exchange between calcium and heavy metal ions. In the experiment of water flow through a permeable model made of soil with calcium carbonate crystals adhered to the surface of soil particles, it was found that the amount of heavy metal ions in the water increased with the time that the water containing heavy metal ions passed through the model.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

透過性地中壁を使った地下水浄化技術は，汚染サイトに対する安定処理と比べ施工ボリュームが小さく，また数十年オーダーの継続利用にかかるランニングコストはゼロである。全体に低コストなこの技術を，重金属を含む地下水の浄化に利用できる十分な可能性を本研究において室内実験で確認できたことは，地下水汚染の拡大エリアにおける食の安全や土地利用拡大の観点から極めて意義深い。