IMAGING MINERAL-WATER INTERFACES

The reactivity of mineral surfaces in the presence of water is central to a vast array of geochemical processes. A fundamental understanding of these reactions, however, ultimately rests on our ability to visualize such interfaces before, during and after reactions in complex environments through in-situ measurements with Å-scale resolution so that elementary processes can be resolved. Recent advances in imaging interfacial processes with various extensions of high resolution X-ray scattering will be described, specifically those that illustrate elemental/chemical sensitivities, lateral spatial resolution, and temporal resolution. Examples include: 1) imaging adsorbate distributions above an interface; 2) imaging sub-nanometer high interfacial topography with X-ray microscopy; and 3) observing interfacial reactions in real-time at elevated temperature and extreme pH. We will discuss the possible future impact of these capabilities to understand increasingly complex phenomena at ever more realistic conditions.

This research was sponsored by the Division of Chemical Sciences, Geosciences and Biosciences, U.S. Department of Energy.