Current Projects
Currently, I apply this approach to understand how Ca2+ influences the sorption of organic matter to mineral surfaces via cation bridging in calcite-rich sediments, which can serve to stabilize organic matter against mineralization. I use nanoscale imaging techniques to assess the importance and distribution of Ca-organic matter complexes in sediment. The coordination environment of Ca2+ by organic matter is being investigated using a combination of Ca K-edge XAS performed at SSRL, and density functional theory and molecular dynamics simulations performed at EMSL and supported by an active user proposal there.
In addition, I lead a NAWI-funded project aimed at quantifying rates in scale formation in brines produced during desalination used to produce clean, potable water. Management of the brine produced as a waste product of reverse osmosis is a major environmental and technical challenge. To achieve high water recovery and enable valorization processes, brines must be concentrated to high salinities. At these high solute concentrations, unwanted precipitation on membranes and other surfaces, called "scaling" limits the efficacy and lifespan of both membrane and evaporative technologies. Advanced synchrotron-based X-ray methods will be used to characterize rates of mineral (Ca/Ba/Sr sulfates, silica) nucleation and growth in a high throughput fashion, enabling exploration of a large brine chemistry matrix.