Improvement of anion adsorption capacity by controlling the crystallinity of the ternary mixed hydrous oxides

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K12293
• 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: Shimane University
• Principal Investigator: Kuwabara Tomoyuki 島根大学, 学術研究院環境システム科学系, 教授 (10397854)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 含水酸化物 / 吸着 / フッ化物イオン

Outline of Final Research Achievements

In order to improve the anion adsorption capacity of a Ternary Mixed Hydrous Oxide composed of silicon, aluminum and magnesium in a 1:1:8 ratio (SAM118), SAM118 samples with different crystallinity were synthesized and the fluoride ion adsorption capacity was evaluated. When the aging temperature of the hydrous oxide slurry was changed, magnesium hydroxide crystallized at 60°C or higher, and the fluoride ion adsorption capacity decreased at higher temperatures. In addition, fluoride ion adsorption by ion exchange with chloride ions between the layers of the hydrotalcite-like compound that constitutes the SAM118 sample was investigated. As a result, it was shown that ion exchange between the layers is not the adsorption mechanism for fluoride. Finally, it was revealed that amorphous magnesium hydroxide is important for fluoride ion adsorption by SAM118.

Free Research Field

環境生態工学

Academic Significance and Societal Importance of the Research Achievements

ありふれた元素を組み合わせることによって，安価で高性能な水処理用の吸着剤を開発することが本研究の目的です。研究対象のケイ素とアルミニウムとマグネシウムの複合含水酸化物は結晶質と不規則な非晶質を含んでおり，今回の研究でフッ化物イオンの吸着には非晶質な水酸化マグネシウムが重要な働きをすることが明らかになりました。今後，非晶質の金属含有量を増加させることで，現状以上に吸着量を増加させた吸着剤に改良できる可能性が示されました。