SEM of Mg/Pd

1

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-kTATPTATP
• Acetone was observed as major byproduct
• Other byproducts being explored
• CO2, ethane, O2, and methane
• Half-life for TATP degradation 11.5 min

TATP
AAcetone
ATATP
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-kTNTTNT
• Byproducts observed
• 2,4-dinitrotoluene (DNT)
• 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitro
  toluene (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
Metal Half-Life (min)
Fe NA
Mg/Pd 25
Fe/Pd 3
Fe/Ni 51
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-kRDXRDX
• Common cyclic byproducts are not observed which
  suggests
• ring cleavage
• production of lower molecular weight gases
• Half-life data for RDX degradation

Fe/Pd
Mg/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 (RH, CH3)
• Mechanically alloyed zero-valent metals are
  combined with known hydrogenation/reduction
  catalysts
• Pd and Ni

Fe/Ni
Fe
SEM of Mg/Pd
Metal Half-Life (min)
Fe NA
Mg/Pd 92
Fe/Pd 210
Fe/Ni 433
Kinetic data of RDX degradation with various
bimetals/metals