IEC 136 |
| Debra R. Rolison, Lala R. Qadir, Elizabeth J.O. Atkinson, Karen E. Swider Lyons, and Veronica M. Cepak. Surface Chemistry Branch, Naval Research Laboratory, Code 6170, 4555 Overlook Avenue, SW, Washington, DC 20375 |
| Although ultrasonic conditions are supposed to create temperatures and pressures in aqueous media that generate extremely reactive chemicals (including hydroxyl radicals) that can decompose environmentally persistent molecules, our study demonstrates that ultrasound alone cannot degrade the energetic compounds RDX (cyclo-1,3,5-trinitramine-2,4,6-trimethylene) and ADN (ammonium dinitramide) in aqueous solution. Effective degradation of near-saturated solutions of these nitramines can be achieved with ultrasonic irradiation of microheterogeneous media containing aluminum powder (a strong reductant) and at basic pH (~12). Sonication without Al powder and base yields minimal degradation of either RDX and ADN (~5-10%) or the nitrite/nitrate ions that are expected byproducts during RDX and ADN degradation. Electrochemical studies and product analyses indicate that in-situ ultrasonic generation of metallic aluminum and/or aluminum hydride drives reductive denitration of the nitramines with 74% of the RDX and 86% of the ADN decomposing within the first 20 min of sonication (20kHz; 50W; 5°C). Disruption of the passive aluminum oxide coating by the microjets created by cavitational implosion exposes the reductant in situ and offers a strategy for effective and rapid waste remediation of energetic waste compounds. |
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Nanotechnology and the Environment
5:00 PM-7:00 PM, Tuesday, March 25, 2003 Convention Center -- Hall G, Poster
Division of Industrial and Engineering Chemistry |