2025-11-21 パシフィック・ノースウェスト国立研究所（PNNL）
Researchers determined that the aluminum-based mineral gibbsite dissolves via dimeric complexes, a more complicated process than the one originally proposed.(Nathan Johnson | Pacific Northwest National Laboratory)
＜関連情報＞
- https://www.pnnl.gov/publications/bridging-molecular-and-macroscale-controls-mineral-dissolution
- https://www.pnas.org/doi/10.1073/pnas.2504109122
二量体複合体による鉱物の溶解 Mineral dissolution by dimeric complexes
Xiaoxu Li, Qing Guo, Yatong Zhao, +14 , and Xin Zhang
Proceedings of the National Academy of Sciences Published:October 6, 2025
DOI:https://doi.org/10.1073/pnas.2504109122
Significance
Mineral dissolution is central to weathering, reactive flow and transport, ore processing, and more. Interpreting observed rates in terms of a molecular scale dissolution mechanism often requires assumptions about the detaching group. The finding that monomeric building blocks can detach more readily as pairs forces us to rethink those assumptions and refine mechanistic models to more reliably predict dissolution rates across a range of conditions.
Abstract
Mineral dissolution is typically thought to occur by the detachment of monomeric building blocks of the crystal structure, although direct evidence is rare. Using in situ high-speed atomic force microscopy to examine step-edge retreat dynamics at high resolution, we report that the dissolution of gibbsite in alkaline solutions occurs mainly by the release of aluminate dimers, which subsequently dissociate into the monomeric species that dominate the solution. The observed dissolution anisotropy is readily explained by this mechanism, which was further supported by density functional tight-binding simulations of detachment activation energies. Recognition that such polynuclear dissolution mechanisms exist may enable an improved understanding of processes regulating mineral dissolution rates in nature and industry.
