Sol-gel revitalization of porous refractory ceramics

The honeycomb structured supports are widely applied in heterogeneous catalysis, in separative processes (filtration, adsorption), etc. If the mentioned porous bodies are manufactured using refractory ceramics precursors (powders) or enter in the refractory state after proceeding, it appears often difficult to fulfil these supports with chemically bonded active components because of their surfaces are drastically deprived from functional active centers being able to be involved into the reactions of ion exchange (for instance, Bronsted acid (BA) centers Cation–O…..H acting as H+ ion exchangers). We suggest applying the sol-gel (SG) method for making the surfaces of refractory porous ceramics highly hydrophilic and able to promote the H+ ion exchange reactions. In particular, it may be seen that several layers of activated alumina gamma-Al2O3 (for example – 5 layers) deposited using the SG technics on the surface of a refractory honeycomb lozenge constituted with alpha-Al2O3 completely reverse the surface acidity type: the initial refractory surface multi-layered with gamma-alumina deposits manifests a domination of BA-centers obligatorily required for its efficient chemical modification using some widely used industrial technics, such as wet impregnation in aqueous solutions, epitaxial deposition, CVD-ML (ALD), SG and so on. A variant of the SG method implemented in this work was partially inspired by [Macedo M.I.F., Osawa C.C., Bertran C.A., J. Sol-Gel Sci. Techn., 2004, 30, pp. 135-140], but the protocol was profoundly revised and simplified; it is described in detail.Book of Abstracts, p. 14