CHEMICALLY TREATED ACTIVATED CARBON CLOTHS FOR REMOVAL OF VOLATILE ORGANIC CARBONS FROM GAS STREAMS - EVIDENCE FOR ENHANCED PHYSICAL ADSORPTION

The micropore surfaces of activated carbon cloths (ACCs) have been chemically modified by introducing controlled amounts of nitrogen, oxygen, or chlorine on the surface of the micropores. The treatments with ammonia, oxidative reagents, or chlorine produce surfaces that are basic, acidic, and polar, respectively. The modified ACCs were evaluated for removal of several different volatile organic compounds (VOCs) in the 10-1000 ppmv concentration range. VOCs examined included acetaldehyde, acetone, and benzene. Acetaldehyde adsorption capacity increased by 500% with oxidized ACC surfaces as compared to untreated ACC surfaces. Acetone adsorption was also enhanced by 350% on oxidized surfaces. The level of benzene uptake was high with most all of the treated surfaces. Thermal regeneration of the ACCs at 100 degrees C was sufficient to desorb each of the three VOCs without any decrease in the adsorption capacity of the treated ACCs.