Collaborative Proposal: An Integrated Study Of The Controls On Reactivity Of Natural Organic Matter In Porous Media

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0106763MauriceThe work to develop molecular-scale understanding of the interactions of natural organic matter (NOM) with mineral surfaces would quantify how the preferential adsorption of higher molecular-weight and more aromatic NOM components to mineral surfaces (sorptive fractionation) affects both the transformation of terrestrial organic carbon and the transport of pollutants through porous media. The molecular-scale adsorption studies would pursue understanding of NOM adsorption mechanisms characterizing NOM molecular weight distributions in soil pore waters and shallow ground waters to determine whether the lognormal distribution model also holds in subsurface environments. They would quantify how sorptive fractionation of NOM affects the binding and mobility of trace metals and NOM photochemical reactivity. The three broad objectives are:(1) To expand molecular-scale studies aimed at developing a more quantitative and mechanistic understanding of NOM adsorption and fractionation processes;(2) To determine the effect of sorptive fractionation on NOM reactivity with respect to trace-metal binding and mobility with respect to photoreactions;(3) To continue to integrate laboratory and field studies, with the ultimate long-term goal of better understanding adsorption/fractionation phenomena as they actually occur in the field. The proposed research has broad significance within the hydrologic sciences, because NOM is ubiquitous and helps to control mineral soil aggregate stability, and photochemical reactions. As to practical applications, little is known about watershed processes controlling the nature of NOM in water supplies. The drinking water industry must address the problem of disinfectant, with chlorine or ozone and both reactivities depend in large part on NOM aromaticity.