A study of the adsorption and reaction of NO. in the presence of oxygen and water vapour on an activated carbon obtained from oil palm shells is presented. The study is based on the measurement of breakthrough curves, at temperatures between 100 and 150 degrees C, and on the subsequent thermal desorption in a fix bed reactor. The concentration of the gas components, NO, O-2 and H2O, corresponds to a simulation of a flue gas in a coal fired power plant. The experimental results show that the reactions on this system include the simultaneously adsorption, reduction and catalytic oxidation of NO together with the adsorption of created NO2. During desorption NO2 reacts to NO through a reductive desorption process. An acceleration of the NO oxidation occurs when the saturation level of the adsorbed NO is reached, resulting in a maximum on the breakthrough curve. Different adsorbed NO species are formed during the process: one thermal unstable NO, and three thermal stable NO species, NO2, NO and (NO)(2) dimers, respectively. (c) 2006 Elsevier Ltd. All rights reserved.