The adsorption capacity on and the desorption from pure activated carbons, silica and NaX zeolite, of hexamethylcyclotrisiloxane (HMCTS or D-3, a common siloxane impurity in biogases) has been evaluated in laboratory experiments using synthetic biogas. The adsorption mode of this molecule has also been investigated by FT-IR spectroscopy. HMCTS adsorbs on silica by hydrogen bonding on the surface hydroxyl groups. However, its desorption up to 200 degrees C by purging with nitrogen as well as by vacuum treatment, is incomplete, leaving surface hydroxyl groups partially affected. Limited desorption is observed also from activated carbons at temperatures between 20 and 200 degrees C. On zeolite NaX molecular adsorption as well as reactive adsorption occurs, partial desorption being obtained by purging with nitrogen already at room temperature. In the three adsorbents, polymerization of HMCTS to silicone is found during adsorption in dynamic conditions. This is supposed to be the common cause of the only partial regenerability of all these solids after HMCTS adsorption. (C) 2010 Elsevier B.V. All rights reserved.