Deformation of microporous activated carbon adsorbent ACC (adsorbent on the basis of silicon carbide) upon CO2 adsorption has been studied. To solve this problem, a dilatometer was used. Its main part was a line differential transformer, the core of which was connected to the adsorbent by means of a rod. Any changes in the adsorbent height caused a change in the core position in the transformer, which influenced the signal recorded from its secondary winding. These results were compared with the adsorption isotherms. High sensitivity of the dilatometric method has been shown. The dilatometer used allowed the measurement of absolute deformation in the range 1 x 10(-4) to 3 mm. (C) 2003 Elsevier Inc. All rights reserved.