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National Institute of Environmental Health Sciences

 

University of Kentucky: Details

Superfund Research Program

Chloro-Organic Degradation by Nanosized Metallic Systems and by Chelate-Modified Hydroxyl Radical Reaction

Project Leader: Dibakar Bhattacharyya
Grant Number: P42ES7380
Funding Period: 2000-2013
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Summary

Chlorinated organics bring toxicity from water, soil, and sediment phases, and exert a cumulative, deleterious effect on the environment. Various Superfund sites contain mixtures of RGBs, chloroethylenes, and other compounds. The degradation of chloro-organics to nontoxic, non-chlorinated, and easily biodegradable products will require integrated approaches involving "combined" (reductive and oxidative) remediation technologies. The laboratory’s proposed approach is to use combined technologies, which should lead to significant improvement over current remediation practices by the eliminating the production of chloro-organic intermediates. The research will focus on the degradation of selected RGBs, TCE, and RGB mixtures. A thorough understanding of the reaction kinetics for both steps (reductive and oxidative), the potential role of surfactants, and material (such as doping catalyst metals, chelates) characteristics will be important for the integration of the steps. The approaches taken for reductive dechlorination by bimetallic nanoparticles in polymer media and nanotubes will allow the development of highly controlled structures for high reactivity and stability. The proposed technology will have a significant impact on the role of nanostructured materials and hydroxyl radical/superoxide radical anion reaction pathway in the environmental field for current and future needs. The technique for potential on-site generation of hydrogen peroxide and gluconic acid (iron chelate) provides enzyme (glucose oxidase) immobilization using an innovative approach of layer-by-layer assembled membranes, which should enhance application opportunities at various Superfund sites. Kinetic modeling of both oxidative and reductive systems should establish an excellent foundation for fundamental understanding of bimetallic nanotechnology-based systems and for chelate-modified hydroxyl/superoxide radical-based reactions. Another important aspect of this proposal is that pollutant toxicity will be significantly reduced for both the dechlorination step and the combined reaction systems.

Relevance: The proposed research is expected to have a significant positive impact on pollution remediation through flexible dechlorination technology developments with significant reduction of material usage, and highly improved health benefits through toxicity reduction.