The remediation of contaminated aquifers often is limited by the performance properties of the materials that are available for absorbing and converting the contaminant components. The materials-imposed limitations to trap and treat forms of remediation, whether biotic or abiotic, become more severe as the complexity of the contaminants composition increases. Mixtures of contaminants, especially mixtures of organized and inorganic pollutants are particularly problematic, because different chemistries are generally required to remove each component from the aquifer. Our objective is to design nanostructured oxide and sulfides with exception reactivity and specificity for potential use in advanced remediation schemes. We define nanostructures here as materials in which the structural elements occur on a large scale between 1.0 and 50 nm, including the mesoscopic 2.0 to 50 nm length scale. Our intent is to achieve materials with reactivities and specificities that surpass the performance properties of conventional oxides ion exchange resins and activated carbons. Our studies will lead to improved abiotic approaches to ground water remediation, as well as to improved microbial remediation by reducing the levels of aquifer contaminants that are toxic to microbes. The targeted contaminants include chlorinated hydrocarbons that are commonly found in superfund sites (e.g., trichloroethylene, dichloroethylene), as well as cationic and anionic forms of metals that are superfund contaminants and members of the top EPA hazardous substances (e.g., arsenic, lead, mercury, cadmium, and chromium). This project complements the microbial remediation studies of Projects 1,3 and 5 of this proposal as it provides alternative strategies for addressing he remediation of ground waters under conditions that would normally compromise microorganism metabolism. The basic chemistry we propose also show be applicable to the removal of inorganics from drinking water at the tap (e.g., arsenite/arsenate) and from industrial waste systems.
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