Potential Usage of Aqueous Alum for Decomposition of Chemical Warfare Agents. Part 2: Reactions with VX and QL

Aluminium sulfate and sodium aluminate buffer solutions for the destruction of phosphorus based chemical warfare agents

“…Evidence for VX hydrolysis has already been documented via NMR under the basic regime at pH 12, but the presence of EA-2192 was observed as were other basic hydrolysis products such as EMPA all in the form of their sodium salts 2, 12 Wagner et al previously demonstrated that nano-sized Al 2 O 3 was effective in catalytically cleaving the P-S bond in VX, and that the cleavage of the O-Et bond which yields the toxic EA-2192 was not observed. 10 As mentioned earlier, no hydrolysis products could be observed in the NMR spectra for the 4100 fold studies nor were they extractable in CHCl 3 for the 41000 fold studies.…”

“…Preliminary studies also showed that there was no advantage to elevating the temperatures for these reactions, 12 adding an additional attractive benefit to alum hydrolysis. Furthermore, with the products sequestered in the alum floc, landfill burial would be possible since over time this material mineralizes to gibbsite, 7 thus making it inaccessible for recovery and reconstitution into CWA's, another one of the major concerns.…”

“…In preliminary feasibility studies, we demonstrated that buffered aqueous aluminium sulfate solutions were effective for destroying GB, GD (2,2-dimethyl-1-methylpropyl methylphosphonofluoridate or soman), and VX as well as a variety of simulants such as triethyl phosphate (TEP) and tri-n-butyl phosphate (TBP). 11,12 In these preliminary studies, the aluminium molar concentration was at least 100 times that of the agent being treated, but the reactions were not monitored with respect to buffer-controlled experiments, so we were unable to determine if the alum buffers were kinetically superior to simple pH buffers. For those studies, alum buffers were prepared by varying the ratios of sodium aluminate and alum solutions as mentioned earlier and two major regimes were monitored-one at pH 4 and the other at pH 12.…”

“…The results were encouraging in that VX, GD, and GB were hydrolyzed at ambient temperature in either regime, and in the acidic buffers, the hydrolysis products were precipitated from solution. 11,12 Evidence for hydrolysis was observed very clearly under basic conditions in 31 P nuclear magnetic resonance (NMR) spectra showing the formation of dealkylated and defluorinated products in the case of G agents, and ethyl methyl phosphonic acid (EMPA) and other products, notably the very toxic S-[2-(diisopropyl-amino)-ethyl]methylphosphonothiolate (EA-2192), in the case of VX. The evidence under acidic conditions was not as clear since, as mentioned above, hydrolysis products never appeared in the spectra, thus leading to the speculation that they were precipitated with the alum floc which ensued upon treatment.…”

Group 13 chelates in nerve gas agent and pesticide dealkylation

“…12 Nanocrystalline metal oxides as catalysts for nerve agent destruction have also been investigated by various research-ers, [13][14][15] and more recently, studies conducted at the US Army Edgewood Chemical and Biological Center at Aberdeen Proving Ground, Maryland, have shown aqueous solutions of aluminium sulfate and sodium aluminate buffered to pH 4 to be very promising for destroying large quantities of VX, GB and GD. 16 The search for alternative agents for decontamination of organophosphate nerve agents and pesticides still continues.…”