Recent advances in surface, interface, and environmental geochemistry

In the last 40 years, a number of surface-sensitive microscopy, modeling, scattering, and spectroscopy techniques have emerged that allow in-situ characterization of the compositions, nanomorphologies, and electronic/geometric structures of the near-surface regions of minerals in contact with water. Synchrotron-based methods, in particular, are revolutionizing our understanding of the electronic/geometric structures of hydrated mineral surfaces, the nature of the EDL, the structure and mode of attachment of adsorbed cations/anions, and, more generally, factors that affect surface chemical reactivity. Here we review some of the historical developments in interface chemistry and the results of recent synchrotron-based studies of water interacting with mineral surfaces and its effect on the geometric structure of mineral surfaces, as well as adsorbate-surface interactions. We also focus on applications of these methods to environmental geochemistry, which involve determining the speciation, spatial distribution, and association of environmental contaminants and pollutants, including some methods capable of imaging and spectroscopic characterization at 25 nm spatial scales.