(248g) Effect of Pore Size Distribution and Surface Area of Activated Carbon Fabrics for the Liquid Phase Adsorption of Chemical Warfare Agent Simulants

The ease and effectiveness of decontamination of surfaces exposed to chemical warfare agents (CWA) are crucial to the protection of the public and military personnel. Recent developments in woven cloths subjected to carbonization and activation processes (activated carbon fabric, ACF) is creating interest in the use of these materials as absorbents for CWA decontamination. Further, wetted ACF's have been demonstrated to function better than the adsorbents that are currently used.

This research focused on the effect of pore size distribution on the ability of an ACF to adsorb half-mustard, 2-chloroethyl ethyl sulfide (CEES), a CWA simulant.

Various ACF's were characterized using nitrogen adsorption at 77K over a wide range of relative pressures (P/Psat N2 from 1x10-6 to 0.995). The mesopore pore size distribution was determined using an algorithm based upon the Kelvin Equation, assuming an open ended cylindrical pore model (BJH method). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were also utilized to illustrate the material topography and crystallinity. One typical example had a surface area of 1050 m2/g, a total pore volume of 0.87 cm3/g, and a mean pore radius of 2.9 nm.

The ability of the ACF's to adsorb CEES from solution in a carrier liquid (methyl nonafluoroisobutyl ether or ethyl nonafluoroisobutyl ether) was then examined. The carrier liquid facilitates the effective transfer of the contaminant from the surface to be cleaned to the matrix of the wipe. ACF's of ranging pore diameters and surface areas were analyzed and a correlation between the pore structure of an ACF and its ability to remove a CWA simulant from solution in a carrier liquid has been found.