The use of hydrofluoroether liquid wetted wipes for the decontamination of sensitive equipment is attracting great interest. Contacting the contaminated equipment with such wipes results in the rapid removal of surface contaminants. Because adsorption from the liquid phase involves larger molecules than those found in the gas phase, the pores in the activated carbon needed to capture contaminants require pores with diameters above the micropore range (diameters <2 nm). In this work, the effects of the specific surface area (900-1300 m 2 /g), the total pore volume (0.40-0.70 cm 3 /g), and the pore size distribution (mean pore diameter ranged from <0.1 to 2.9 nm) of commercially available activated carbon fabrics (ACF) on the removal of 2-chloroethyl ethyl sulfide, a chemical warfare agent (CWA) simulant, from solution in hydrofluoroethers were examined. The highest adsorption loadings were obtained with the ACF with a mean pore diameter of 2.9 nm.

The environmental fate of chemical warfare agents is a current concern, and the notorious persistency of mustard in soil is well-known. The current study utilizes 13C MAS NMR as an in situ method to study the behavior of mustard, and the common simulants 2-chloroethyl methyl sulfide (CEMS) and 2-chloroethyl phenyl sulfide (CEPS), in a sandy loam soil. Spreading of these water-insoluble liquids and surface sorption on the dry soil particles is observable, as is the recoalescence of liquid droplets and/or hydrolysis in the presence of added water. The relative hydrolysis rates are in agreement with those observed in solution. CEMS, possessing the shortest aqueous half-life, hydrolyzes without droplet reformation. But mustard and CEPS, possessing much longer aqueous half-lives, do not substantially hydrolyze prior to droplet reformation. For mustard, this behavior is crucial to its longevity in soil. Hydrolysis of CEMS and CEPS in the sandy loam soil yields predominately their corresponding alcohols, with some ether formation for the latter. Mustard hydrolysis in the sandy loam soil results in the nearly exclusive formation of the branched sulfonium ion HOCH2CH2SCH2CH2S+(CH2CH2OH)2 (CH-TG). A simple model based on droplet size is presented to explain the persistency of mustard in soil.

Magic angle spinning (MAS) NMR can distinguish between molecules adsorbed in monolayers within the micropores (> 20 A) of activated charcoal and those present in multilayers or capillary-condensed liquid in the mesopores (20-500 A). The differentiation is possible due to the NMR shifts to low frequency induced by the large, diamagnetic susceptibility of the graphitic surface of the micropores (upon which primary adsorption occurs) in combination with slow molecular exchange between the micropores and mesopores. This study uses MAS NMR to characterize the adsorption and oxidation of 2-chloroethyl phenyl sulfide (CEPS) on activated charcoal. Micropore-filling by solvents and solvent displacement of micropore-adsorbed CEPS are also demonstrated for charcoal using this technique.