Coke dispersion in carbon–mineral porous adsorbents Original Research Article

The morphology, dispersion and localization of coke in coked alumina and silica have been investigated by a newly developed technique, which can be applied 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 predominantly located in the pores of silica gel. Probably the pores filled with coke are formed by the tetrahedron packed SiO2 globules. On the other hand, the intensity of coke formation on the alumina surface is considerably higher then on the silica surface, so coke formation is accompanied by the total surface coverage at low amounts of coke deposited. Possible reasons for these differences are considered.