Organo-mineral interface processes and element cycling

We characterize electron transfer, mineral dissolution and precipitation, metal transformation, and molecular fractionation of organic matter at mineral-water-organic matter-microbe interfaces.

Organo-mineral interface reactions control element mobility, contaminant speciation, and organic carbon stabilization in tailings and degraded soils. This direction focuses on mineral weathering, sulfur and iron redox processes, metal retention, dissolved organic matter molecular fractionation, and microbially mediated interfacial transformations.

Using synchrotron-based XAFS/STXM, NanoSIMS, FTICR-MS, Orbitrap-MS, and related techniques, we resolve the binding forms, spatial distribution, and reaction pathways of organic matter associated with Fe, Al, and Si mineral phases from molecular to nano- and micrometer scales.

Microscopic and spectroscopic evidence for mineral weathering and interfacial reactions — Micro-scale morphology, elemental occurrence, and synchrotron spectroscopic information help identify primary mineral weathering, secondary mineral formation, and changes in metal speciation.

Multi-scale morphology, elemental distribution, and spectroscopy of organo-mineral complexes — Microscopic imaging, elemental mapping, X-ray diffraction/absorption spectroscopy, and NanoSIMS are used to resolve spatial coupling among Fe-Si secondary minerals, organic carbon, and aggregate microstructures.