A method for obtaining carbonaceous adsorbents from used corrugated cardboard by physical activation with CO2 is described. The effect of pyrolysis temperature (500-800 degrees C) and time (30 and 60 min) as well as activation on the adsorbents textural parameters, acid-base character of surface and sorption properties toward nitrogen dioxide have been tested. The products were microporous carbons of rather low surface area ranging from 13 to 278 m(2)/g and pore volume from 0.02 to 0.19 cm(3)/g, showing a very strong basic character of the surface. The results have proved that a proper choice of cardboard pyrolysis and activation procedure can produce adsorbents with a high capacity for nitrogen dioxide, reaching to 27.8 and 106.1 mg NO2/g in dry and wet conditions, respectively. (c) 2012 Elsevier B.V. All rights reserved.