The possibility of changing waste paper sludge into valuable carbonaceous adsorbent was tested. The performance of three types of samples obtained from this waste was studied: chars (PK), activated chars (PKA) and activated initial material (PA). Pyrolysis of the initial material was carried out at 550, 600 and 700 degrees C, while the activation of the initial material and chars obtained with CO2 at 550,600 and 700 C. The sorption capacity of carbonaceous adsorbents obtained was evaluated on the basis of NO2 adsorption in dry and wet conditions. The NO2 sorption properties of the activates decrease with increasing temperature of activation and the maximum sorption capacity was noted for the samples activated at 550 degrees C. On the basis of measurements in dry and wet conditions, the presence of water was found to increase the NO2 breakthrough capacity. The NO2 sorption capacity of the adsorbents obtained depended on the type and temperature of modification process and acid-base properties of the materials obtained. (C) 2011 Elsevier B.V. All rights reserved.