(583aj) Screening Of Metal Catalysts For Contaminant Removal in Water

Water pollution is a large problem in the United States and elsewhere. We have long been concerned with contaminants from agricultural run-off and industrial waste. Concerns are now shifting to emerging pharmaceutical and personal care product (PPCP) contaminants, which enter the water system through municipal wastewater. These compounds tend to have recalcitrant chemical structures, making them difficult to remove using conventional treatment techniques. Broadly applicable techniques are needed to remediate these pollutants from the water system, and catalysis is a promising strategy. In this work, we explore the possibility of using supported Au-based catalysts to decompose both traditional fertilizer and emerging PPCP contaminants in a water environment. We are specifically interested in catalysis for reduction of nitrates, which are broadly representative of fertilizer residuals, and decomposition of valerolactone, which represents a variety of recalcitrant PPCP compounds. We screen different bimetallic and trimetallic Au-based catalysts for their abilities to decompose these compounds in water using density functional theory simulations of small metal catalyst models supported on metal oxide lattices. Compositions are changed by replacing one or two Au atoms with a more reactive transition metal such as Cu, In, Fe, Nb, Pd, or Ti to screen for optimal activity. We use a variety of implicit and explicit solvation models to model the water environment. Preliminary results, which form the basis for general modeling of supported Au catalysts in water, suggest AuFe and AuPd are active for nitrate reduction.