Research

Ionic substitution and solid solutions in minerals

In various geological systems, minerals rarely occur as a pure end-member but form solid solution to a certain degree or contain trace amounts of foreign ions in their structures. There have been numerous field and experimental studies investigating ionic substitution in minerals, while quantifying their thermodynamics and mechanisms are often difficult to empirically obtain. I seek to explore ionic substitution in the mineral structure in atomistic scales mainly based on density functional theory (DFT) calculation. Combined with statistical thermodynamic analysis, DFT modeling can be very useful to investigate complex solid solution systems (e.g., involving multiple atomic sites) allowing for predicting energetic stabilities of minerals in hydrothermal and magmatic systems.

Mineral replacement

The mineral replacement is a coupled dissolution-growth process in which a primary mineral dissolves in contact with fluid and is replaced by a more stable secondary mineral. Understanding mineral replacement reactions is essential in many natural and industrial processes including metasomatism, diagenesis, and metamorphism, and nuclear waste disposal. My research explores mechanistic understanding of mineral replacements based on synchrotron nanoscale X-ray imaging. Combined experimental and analytical approaches have been developed to understand how mineral replacement is modified by the crystallography of the primary and secondary mineral.

Redox transformation mediated by semiconducting minerals

Some transition metal-bearing minerals can facilitate otherwise slow electron transfer processes between various chemical species. This has been considered an important process that controls redox reactions in natural and engineered systems. I use electrochemical setups that allow to simulate electron-accepting and -donating behavior of chemical species as catalyzed by natural minerals such as magnetite and pyrite. This novel approach enables me to diagnose reaction mechanisms and kinetics of electron transfer through the mineral structure and surface.