Study of the effects of activated carbon oxidation with sulphuric acid and impregnation with copper sulphate on the protection capacity of gas filters against ammonia

Abstract

The objective of this paper has been the study of the possibility to enhance the properties of activated carbon (AC) for using it in respiratory protective devices for ammonia removal from the air. The commercial AC samples were oxidized with different amounts of 10% and 15% sulphuric acid solutions. The acid treated AC samples were the loaded with copper sulphate with twofold impregnation by the incipient wetness method. The impregnated AC was tested in a packed bed in the gas filter with a diameter of 105 mm and a bed depth ranging from 29 mm to 41 mm under the following test conditions inlet concentration of ammonia was 3,5 mg/dm3, flow rate of 30 dm3/min at 70% relative humidity and ambient temperature. The breakthrough was detected qualitatively by the phenolphtalein indicator paper. The new impregnated AC reached the breaktrough time of 108 min for a 29 mm bed depth, and 160 min for a bed depth of 41 mm.