EFFECTS OF ENVIRONMENTAL WEATHERING ON THE PROPERTIES OF ASC-WHETLERITE

Activated, impregnated carbon from a radial flow air purification filter was separated into fractions after the filter had been exposed to shipboard environmental conditions for 21 months. Carbon samples from the discrete filter locations were analyzed using surface analysis methods. Breakthrough times of the segregated carbon fractions were recorded for a cyanogen chloride challenge. The inlet portion of the filter was most severely affected by the weathering. For carbon removed from the filter inlet, the weathering process caused impregnants to leach from the granules and form metal sulfates, presumably by reaction with atmospheric SO(x). No sulfur was detected on carbon samples removed from the center and outlet portions of the filter; however, a significant fraction of the chromium (VI) impregnant had been reduced to chromium(III). In all cases, breakthrough times recorded for a cyanogen chloride challenge were significantly less than that recorded for the unweathered carbon sample.