The chemistry of environmental interfaces plays a major role in controlling the fate, mobility and 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 and antimony.
The rate and extent of reactions at environmental surfaces are controlled by the structure and composition of the interface. We focus much of our effort 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 utilizes synchrotron based x-ray scattering and spectroscopic techniques to provide information about interface structure and speciation in both model system studies and in the analysis of materials from field 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 characterizing the composition and surface properties of materials. We use computational methods such as periodic density functional theory, as well as thermodynamic models to couple experimental analysis of structure and speciation with theoretical analysis of reactivity trends.