The chemistry of environmental interfaces plays a major role in dictating the fate, mobility and ultimate bioavailability of trace chemical species in the environment. The central theme of our research group is the development of a detailed understanding of the surface chemistry of natural materials (e.g. colloids, mineral grains, atmospheric aerosols etc.) in order to improve both conceptual and quantitative models of the fate, transport and biogeochemical cycling of trace elements. Our current work is focused largely on the surface chemistry of naturally abundant iron-(oxy)hydroxide mineral phases and their interaction with trace contaminants such as lead, arsenic, antimony and mercury.

The specific environmental interface reactions and reactivity are dictated by interfacial structure and composition. Therefore we are focused on experimental and computational studies of mineral-fluid interface structure, thermodynamics and structure-reactivity relationships, and how these properties are evident in field scale analysis of trace element speciation. The experimental work mainly utilizes synchrotron based x-ray scattering and spectroscopic techniques to provide interface structure and speciation in both carefully controlled model system studies and in the analysis of materials from impacted sites. We also make use of numerous other techniques such as atomic force microscopy, ICP-mass spectrometry, x-ray fluorescence, dynamic light scattering and zeta potential measurements for characterization of composition, and surface characterization. We use computational methods such as periodic density functional theory, as well as thermodynamic models to couple our experimental analysis of structure and speciation with theoretical analysis of reactivity trends.