The effects of airborne contaminant exposure in humid air on the physical properties and filtration capabilities of a copper/zinc/molybdenum impregnated carbon were investigated.
The impregnated carbon was exposed individually to CO 2 , NH 3 and NO 2 in humid air, then evaluated for changes in metal speciation, metal distribution, porosity and water-uptake.
The exposed impregnated carbon was further evaluated for changes in its ability to remove SO 2 and cyclohexane from air streams. Exposure to CO 2 did not impact the physical properties of the impregnated carbon, with changes in filtration performance were not evident.
NH 3 exposure resulted in the formation of metal amine complexes, which led to a migration of impregnants from within the pores of the carbon granule to the external surface.
NH 3 exposure increased SO 2 filtration while decreasing cyclohexane filtration. The decrease in cyclohexane filtration was attributed to an increase in water uptake and a decrease in porosity. NO 2 exposure significantly decreased the porosity of the carbon substrate while increasing the amount of surface oxygen. The increased surface oxygen greatly increased water uptake. NO 2 exposure greatly reduced the SO 2 breakthrough time and the ability of the material to remove cyclohexane.