IEC 68 |
| Dibakar Bhattacharyya1, David Meyer1, Leonidas Bachas2, and Stephen M.C. Ritchie3. (1) Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506, (2) Department of Chemistry, University of Kentucky, Rose Street, Lexington, KY 40506-0055, (3) Department of Chemical Engineering, University of Alabama, Box 870203, Tuscaloosa, AL 35487-0203 |
| Membrane-immobilization is used to establish the enhanced dehalogenation rates obtained when using nanoscale zero-valent iron (Fe0) for the reductive destruction of toxic organic compounds. In addition to in-situ synthesis of nanoparticles, membranes play an important role in solute partitioning. Nanoparticles can be synthesized in membranes by four different approaches: (1) using polymeric ligand and ion exchange followed by reduction, (2) using metal-carbonyl, (3) with diblock copolymers and metal salts, and (4) by phase inversion technique. Thin films of cellulose acetate containing immobilized Fe0 nanoparticles were prepared using phase inversion with borohydride reduction of the metal and used in dehalogenation studies of selected chlorinated organics. The reaction of trichloroethylene (TCE) with nanisized Fe0 particles immobilized in cellulose acetate showed a 15% dechlorination in 1 hour using only milligram quantities of the metal. This corresponds to a surface-area normalized, pseudo-first order rate constant (kSA) value of 0.12 L m-2 h-1, which is about 1000-fold higher than that reported for bulk Fe0. The 1,1,2,2-tetrachloroethane (TtCA) studies yielded a kSA value of 0.17 ± 0.08 L m-2 h-1 using 5 to 8 mg of immobilized Fe0 particles with an average diameter of 25 nm. The development of this technology will have a significant impact on the role of nanostructured materials in the environmental field for current and future needs. Thefundamentally new technique for creating environmentally-applicable nanoparticles in a membrane matrix provides a versatile platform to address diverse needs in both industrial manufacturing and remediation. The authors acknowledge the support of NSF-IGERT, and U.S.EPA STAR Nanotechnolgy grants for the support of this research. |
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Nanotechnology and the Environment
1:30 PM-5:25 PM, Monday, March 24, 2003 Convention Center -- Room 392, Oral
Division of Industrial and Engineering Chemistry |