Reactions at mineral surfaces greatly influence several key (bio)geochemical processes including biomineralization, nutrient and trace element cycling and contaminant dynamics. In this research theme, we focus on the mechanisms and kinetics of mineral nucleation and growth, and how these processes impact the speciation, sequestration or release/transport of various elements in Earth’s surface and (near-)subsurface environments. Currently, we are interested in the formation and/or transformation of calcium carbonates and sulfates, clay minerals, iron (oxyhydr)oxides and sulfides and phosphates (e.g., struvite) in natural and engineered environments.

In order to understand the key controlling factors affecting mineral formation and/or transformation, we make synthetic analogues of these mineral phases and perform experiments under simulated natural conditions. Such an approach allows us to perform in-depth investigations on the how minerals form and break, and how these impact critical (bio)geochemical cycles (e.g., iron, phosphorous, sulfur) as well as the mobility and toxicity of metals and metalloids (e.g., arsenic, chromium, nickel).

We integrate several analytical approaches from inorganic chemistry, materials chemistry and nanoscience to help us gain better understanding on their mineral chemistry. Specifically, we use a suite of laboratory-based solid state and aqueous phase characterization techniques (e.g., TEM, SEM, XRD, IR, ICP-OES/MS, IC) and combine them with synchrotron-based scattering (e.g., SAXS/WAXS, PDF), and spectroscopic (e.g., SXM, XAFS) techniques to probe these reactions at high spatial or temporal resolution.

Current research projects under this research theme include:

• Clay Mineral Formation at Ambient Conditions
• High-Energy X-ray Scattering Studies on Mineral Crystallization
• Experimental Diagenesis and Mineral Transformation Phenomena of Sedimentary Carbonates and Sulphates
• Iron Minerals and their Impact on Nutrients and Trace Elements Cycling
• Struvite Crystallization