Reaction of NO2 with Activated Carbon at Ambient Temperature

NO 2 adsorption on activated carbons at ambient temperature was studied. The adsorbed species after various adsorption times were examined by analyzing the evolution of NO, NO 2, CO, CO 2, and O 2 during thermal desorption. Emission of NO but not NO 2 was observed during the early stage of NO 2 adsorption. From the nitrogen and oxygen balance data, we conclude that NO 2 adsorption involves the reduction of NO 2 to NO driven by oxidation of the carbon surface. The formed NO is either adsorbed on the carbon surface or released as exhaust gas depending on the surface conditions. The adsorbed NO species are released along with O 2 and a small amount of CO 2 and CO at temperatures below 150 °C during heating. NO 2 becomes stable when the carbon surface has been extensively oxidized.