| Project/Area Number |
21K14454
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 27020:Chemical reaction and process system engineering-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
Orita Yasuhiko 東京工業大学, 物質理工学院, 助教 (80883149)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2023: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2022: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2021: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | Supercritical CO2 / nanoparticle / Surface modification / synthesis / extraction / hot-compressed water / 超臨界CO2 / 酸化鉄 / 水熱 / 合成 / 抽出 / supercritical CO2 / iron oxide nanoparticles / surface modification / supercritical extraction / hydrothermal synthesis / flow process / metal oxide nanoparticle / organic modification / slug flow |
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| Outline of Research at the Start |
高密度磁気記録デバイスの産業実用化に向けては，均一粒径・高修飾率の有機修飾ナノ粒子を連続・大量合成するプロセスの確立が必要となる．本研究は，「二段反応場を利用した粒子の形成場と成長場の分割」と「超臨界CO2＋水系のセグメント空間」の融合を念頭に置いた，有機修飾ナノ粒子の連続合成プロセスの構築・設計を目的とする．研究目的の達成に向け，以下の項目を遂行する．
[A] 界面活性剤と相溶する高温高圧水中における有機修飾ナノ粒子の形成機構解明
[B] 水＋超臨界CO2系のセグメント空間における有機修飾ナノ粒子の成長機構解明
[C] 統計熱力学モデルと分子情報を利用した水＋超臨界CO2系の相平衡挙動の把握
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| Outline of Final Research Achievements |
In this research project, we successfully synthesized surface-modified Fe3O4 nanoparticles in hot-compressed water and controlled their surface structure. Additionally, we successfully synthesized Fe2O3 nanoparticles in supercritical CO2 and controlled their particle size, aggregation, and surface structure. We also discovered a novel phenomenon in which CO2 drives the formation of metal oxides under supercritical CO2, allowing the low-temperature synthesis of metal oxide ceramics. Furthermore, we have demonstrated that surface-modified nanoparticles in the aqueous phase can be extracted with nearly 100% efficiency using supercritical CO2. In scCO2 extraction, we have also discovered a phenomenon in which nanoparticles tend to accumulate at the water-supercritical CO2 interface. These research results have led to research achievements in the form of 4 papers and 18 conference presentations (including two invited presentation).
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| Academic Significance and Societal Importance of the Research Achievements |
本研究課題を通じて，金属酸化物系の表面修飾ナノ粒子に対して，「水熱下での晶析機構」，「超臨界CO2中での晶析機構」，「水相から超臨界CO2への抽出挙動」に関する多くの知見を創出することに成功した．特に，超臨界CO2を活用した表面修飾ナノ粒子の合成・抽出は，本研究課題が初めて開拓した学術領域であり，CO2自身による反応駆動効果や水－超臨界CO2界面での粒子集積といった新奇な現象も見出された．従って，これらの研究成果は，CO2利用工学・超臨界流体工学に新たな学術領域を創出し，従来にはない合成・抽出技術へと昇華しうる点に，学術的意義・社会的意義を有している．
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