SEM of Mg/Pd

1. TATP crystal TATP crystal TATP crystal Degradation of TATP, TNT, and RDX using Mechanically Alloyed Bimetals Christian A. Clausen, Cherie L. Geiger, Rebecca Fidler, Michael E. Sigman Department of Chemistry, University of Central Florida Emulsified Zero-Valent Metal (EZVM) Objectives Kinetics Experiments • Optimize the use of zero-valent metals (ZVM), emulsified zero-valent metal (EZVM) systems, and bimetal treatment systems (BTS) to degrade TATP, TNT, and RDX contamination • Develop an in-situ method for degradation of common explosives TATP • Combination of emulsified liquid membranes (ELM) and zero-valent bimetal: • emulsion droplet provides protective reaction barrier • Emulsion droplet: • organic membrane, water interior, surfactant, and active metal • In-situ technology to remediate: • water and soil contamination • wet TATP contamination 20 min • Vial studies performed in methanol/water solution • Pseudo-first order rate law: • rate=-kTATP[TATP] • Acetone was observed as major byproduct • Other byproducts being explored: • CO2, ethane, O2, and methane • Half-life for TATP degradation = 11.5 min TATP A=Acetone A=TATP Micrograph of Emulsion Droplet • Triacetone Triperoxide • Prepared from common materials: • acetone, hydrogen peroxide, and acid catalyst • Sensitive to shock, friction, and heat • High vapor pressure (7 Pa) • Incidents involving TATP: • Richard Reid “The Shoe Bomber” used PETN with TATP (2001) • London bombings (2005) • Oklahoma University (2005) Kinetic data of TATP degradation with MgPd and acetone byproduct production 1 min 6 min 20 min TNT • Vial studies performed in water • Pseudo-first order rate law: • rate=-kTNT[TNT] • Byproducts observed: • 2,4-dinitrotoluene (DNT) • 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene (ADNT) • Half-life data for TNT degradation: Mg/Pd Fe/Pd TATP crystal absorbed into an emulsion MgPd FePd Nitro Explosives Bimetal Treatment System (BTS) • Provides an in situ technique for handling explosive contamination on structures and scrap metal • Paste consisting of active bimetal, solvent and thickeners • Can be applied directly to contaminated structures or scrap metal Fe/Ni Fe Fe FeNi TNT (2,4,6-Trinitrotoluene) RDX (cyclo-1,3,5-trimethylene-2-4-6-trinitramine) Kinetic data of TNT degradation with various bimetals/metals • Environmentally hazardous: • considered toxic and mutagenic • Types of contamination: • soil and groundwater • metal scraps and ordnance Application of BTS RDX Summary and Future Directions • Vial studies performed in water • Pseudo-first order rate law: • rate=-kRDX[RDX] • Common cyclic byproducts are not observed which suggests: • ring cleavage • production of lower molecular weight gases • Half-life data for RDX degradation: Mg/Pd Fe/Pd Zero-Valent Bimetals • Bimetals are shown to successfully degrade nitro explosives (TNT and RDX) and TATP • EZVM and BTS are continued to be explored and optimized to clean-up both dangerous TATP contamination and environmentally hazardous nitro explosives contamination • Further exploration includes: • reaction pathways • final byproducts • Field application: • soil and groundwater nitro explosive contamination near industrial production sites • structures/scrap metal and ordnance due to incomplete detonation • clean-up of TATP residue in underground labs • Zero-valent bimetals have been shown to • reduce chlorinated compounds • Zero-valent substrate provides thermodynamic • driving force: • Mg2+ + 2e- Mg0 Eo = -2.20 V • Fe2+ + 2e‑ Fe0 Eo = -0.44 V • Oxidation reaction provides source of molecular hydrogen: • M0 + ROH  H2 + M2+ (R=H, CH3) • Mechanically alloyed zero-valent metals are combined with known hydrogenation/reduction catalysts: • Pd and Ni Fe/Ni Fe SEM of Mg/Pd Kinetic data of RDX degradation with various bimetals/metals