Routes of photocatalytic destruction of chemical warfare agent simulants

Photocatalytic Oxidation of Dimethyl Methylphosphonate in Aqueous Suspensions of TiO2

“…It was observed in this work that regardless of the initial pH, the initial DMMP concentration and the percent degradation, the final solution pH never dropped below 2.4, approximately the pKa of DMMP. Voronstov [13] reported a minimum pH of about 3 and suggested that the observed pH plateau in the presence of continued DMMP degradation and acid byproduct formation could be attributed to oxidation of the acid byproducts, consistent with the results reported here.…”

“…Photocatalytic oxidation of DMMP using metal oxides including WO 3 [11] and amorphous manganese oxide [12] has been studied, however TiO 2 is the predominant photocatalyst. Previous studies have shown that TiO 2 and UV irradiation can completely degrade DMMP from 2 mM solutions and that the reaction proceeds via oxidation of the methoxy groups followed by oxidation of the methyl group [13]. Oxidation of DMMP to methylphosphonic acid, formaldehyde, formic acid and phosphate with TiO 2 in an air-purged system under 350 nm light and solar irradiation was observed to be sensitive to substrate concentration as well as catalyst type and loading.…”

Photocatalytic oxidation of VX simulant 2-(butylamino)ethanethiol

“…Chemical warfare agents (CWA) mustard gas (bis(2-chloroethyl)sulfide) and VX (S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate) are examples of organic compounds containing sulfur and sulfur plus nitrogen atoms, respectively. The principal possibility for destruction of selected CWA into inorganic products by means of liquid-phase photocatalysis was demonstrated before [8]. However, practical application of photocatalytic water purification from CWA requires high mineralization rates.…”

Titanium dioxide photocatalysis to decompose isopropyl methylphosphonofluoridate (GB) in gas phase

“…For CWAs simulant, dimethyl sulfide (DMS), diethyl sulfide (DES) and 2-chloroethyl ethyl sulfide (2CEES) as 2,2 -dichloro diethyl sulfide (sulfur mustard: HD) simulant as a blister agent [18][19][20][21][22][23][24][25][26][27][28], and dimethyl methyl phosphonate (DMMP) [34][35][36][37][38][39][40][41][42][43] and di-isopropylfluorophosphate (DFP) [44,45] as isopropyl methylphosphonofluoridate, Sarin (GB) and trimethylpropyl methylphosphonofluoridate, tabun (GD) simulant as a nerve agent have been known for major simulants. Complete decomposition of these simulants by TiO 2 photocatalysis and the detailed decomposition mechanism at the surface of TiO 2 photocatalyst are well elucidated and widely known.…”