To avoid the emission of toxic mercury compounds from coal combustion and gasification, efficient gas cleaning systems need to be developed. In this work, the effectiveness of activated carbons for retaining mercury in gases from coal gasification was evaluated and contrasted with the results obtained in a coal combustion atmosphere. The performance of a sulphur-loaded carbon (RBHG3) was compared with that of the same carbon without sulphur (RB3). Minor differences were observed in the two atmospheres studied. The retention of mercury at 120 degreesC was close to 30% in RB3 and up to 70% in RBHG3. (C) 2002 Elsevier Science B.V. All rights reserved.