Paper mill sewage sludge was employed as the raw material for producing activated carbon by physical activation with steam in this study. The important parameters, which greatly affect the characteristics of sludge-based activated carbon (SAC), such as the carbonization temperature, carbonization time, activation temperature and activation time, were investigated. In comparison with the carbonized sludge, SAC was applied to remove methylene blue (MB) from aqueous solution in static and dynamic adsorption experiments. The results indicated that the best quality SAC was obtained at a carbonization temperature of 300 degrees C, carbonization time of 60 min, activation temperature of 850 degrees C and activation time of 40 min. SAC prepared under the optimum conditions had remarkable adsorptive properties and notable treatment effect for MB. Accordingly, it was concluded that the procedure of physical activation with steam could be an environmentally benign and effective approach for preparation of sludge-based adsorbent. (C) 2011 Elsevier B.V. All rights reserved.