Fast water insertion mechanism in rare-earth sulfates

• Project/Area Number: 17K17821
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials/Physical properties; Structural/Functional materials
• Research Institution: Kyoto University
• Principal Investigator: Hatada Naoyuki 京都大学, 工学研究科, 助教 (00712952)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2017: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
• Keywords: 化学蓄熱 / 硫酸塩 / 脱挿入 / 拡散 / 脱水 / 水和 / 拡散係数 / 化学工学 / 省エネルギー / 熱工学 / イオン結晶

Outline of Final Research Achievements

The insertion of water into beta lanthanum sulfate was confirmed to be due to the one-dimensional diffusion between stable positions arranged in a one-dimensional manner in the crystal while maintaining the host crystal structure. Beta lanthanum sulfate powder produced by dehydration of lanthanum sulfate nonahydrate was found to have a microstructure which looks like "platy joints" composed of stacked several hundred nanometer-thick plate-like crystals. The grain boundary diffusion was found to be the origin of the fast insertion/extraction of water.

Academic Significance and Societal Importance of the Research Achievements

化学蓄熱は産業排熱の有効利用のために期待される技術のひとつである。硫酸ランタンは、200℃以下の比較的低温であっても可逆的に水蒸気と反応し、吸熱・発熱を伴って水が脱挿入されるため、この温度域における化学蓄熱技術の開発に向けて興味深い物質である。本研究の意義は、本物質への高速な水の脱挿入メカニズムを解明し、材料組織、結晶構造に立脚した化学蓄熱材の開発指針を提案したことである。

Research Products

• [Journal Article] Multi-step hydration/dehydration mechanisms of rhombohedral Y2(SO4)3: a candidate material for low-temperature thermochemical heat storage (2020)
  • Author(s): Kunihiko Shizume, Naoyuki Hatada, Shoko Yasui, Tetsuya Uda
  • Journal Title: RSC Advances Volume: 10 Issue: 26 Pages: 15604-15613
  • DOI: 10.1039/d0ra02566f
  • Peer Reviewed / Open Access
• [Journal Article] Characteristic microstructure underlying the fast hydration?dehydration reaction of β-La2(SO4)3: “fine platy joints” with “loose grain boundaries” (2018)
  • Author(s): Shizume Kunihiko、Hatada Naoyuki、Toyoura Kazuaki、Uda Tetsuya
  • Journal Title: Journal of Materials Chemistry A Volume: 6 Issue: 48 Pages: 24956-24964
  • DOI: 10.1039/c8ta06721j
  • Peer Reviewed
• [Presentation] 低温動作化学蓄熱材開発へ向けた菱面体晶系金属硫酸塩の水和反応挙動調査 (2019)
  • Author(s): 鎮目邦彦, 畑田直行, 安井詔子, 宇田哲也
  • Organizer: 化学工学会第84年会
• [Presentation] Dehydration-hydration behaviors of lanthanum compounds as potential thermochemical heat storage materials (2019)
  • Author(s): Naoyuki Hatada, Kunihiko Shizume, Kazuaki Toyoura, Tetsuya Uda
  • Organizer: The 10th Pacific Rim International Conference on Advanced Materials and Processing (PRICM-10)
• [Presentation] Reversible hydration-dehydration reaction of yttrium sulfate as a new candidate of thermal energy storage material for low-temperature waste heat (2019)
  • Author(s): Kunihiko Shizume, Naoyuki Hatada, Shoko Yasui, Tetsuya Uda
  • Organizer: The 10th Pacific Rim International Conference on Advanced Materials and Processing (PRICM-10)
• [Presentation] 各種金属硫酸塩が持つ結晶内の細孔へのアンモニア分子の脱挿入挙動の調査 (2019)
  • Author(s): 鎮目邦彦, 畑田直行, 豊浦和明, 田居宏隆, 宇田哲也
  • Organizer: 資源・素材2019（京都）
• [Presentation] Comprehensive analysis of dehydration-hydration reaction cycle of rare earth compounds for potential thermochemical heat storage materials (2019)
  • Author(s): Kunihiko Shizume, Naoyuki Hatada, Kazuaki Toyoura, Hirotaka Tai, Shoko Yasui, Tetsuya Uda
  • Organizer: The Fifth International Symposium on Innovative Materials and Processes in Energy Systems (IMPRES2019)
• [Presentation] 低温動作化学蓄熱材開発へ向けた菱面体晶系金属硫酸塩の水和反応挙動調査 (2019)
  • Author(s): 鎮目邦彦、畑田直行、安井詔子、宇田哲也
  • Organizer: 化学工学会第84年会
• [Presentation] 化学蓄熱材ベータ硫酸ランタンの比表面積の評価と水和反応速度への影響 (2018)
  • Author(s): 鎮目邦彦、畑田直行、鹿住健司、宇田哲也
  • Organizer: 化学工学会 第83年会
• [Presentation] 硫酸ランタンへの水の脱挿入と化学蓄熱への応用 (2017)
  • Author(s): 畑田直行、鎮目邦彦、豊浦和明、田居宏隆、宇田哲也
  • Organizer: 第13回固体イオニクスセミナー
• [Presentation] 新規化学蓄熱材候補：ベータ硫酸ランタンにおける微細組織の形成と水和反応の速度論 (2017)
  • Author(s): 鎮目邦彦、畑田直行、豊浦和明、田居宏隆、鹿住健司、佐々木宣治、宇田哲也
  • Organizer: 化学工学会 第49回秋季大会
• [Remarks] 研究紹介 - 京都大学材料工学専攻 宇田研究室
  • URL: https://www.aqua.mtl.kyoto-u.ac.jp/wordpress/research/