Coke dispersion in carbon-mineral porous adsorbents

The morphology, dispersion and localization of coke in coked alumina and si lica have been investigated by a newly developed technique, which can be ap plied generally for studies of other systems of 'support+modifier' type. It is shown that, at the considered amounts of coke. deposited coke clusters partially cover the surface of silica leading to a mosaic-like structure of the resulting carbon-mineral material surface. These clusters are predomin antly located in the pores of silica gel. Probably the pores filled with co ke are formed by the tetrahedron packed SiO2 globules. On the other hand, t he intensity of coke formation on the alumina surface is considerably highe r then on the silica surface, so coke formation is accompanied by the total surface coverage at low amounts of coke deposited. Possible reasons for th ese differences are considered. (C) 2001 Elsevier Science Ltd. All rights r eserved.