1987 Volume 20 Issue 2 Pages 117-123
Nickel concentration profiles were studied for impregnated nickel/alumina catalysts prepared by impregnating two types of spherical aluminas with nickel (II) chloride aqueous solution and applying a wide range of postimpregnation drying conditions. Migration of nickel (II) ion towards the outer surface of alumina occurred during post-impregnation drying. The fraction of migrated nickel (II) ion increased with increase of the constant drying rate, and was held at a constant value, 0.5, at values of the constant drying rate larger than 2 × 10-4kg•m--2•-1.
A model of solute migration during post-impregnation drying, combining solution movement by a capillary force with solute diffusion, was proposed. The observed nickel concentration profiles of the nickel/alumina catalysts showed good agreement with the results calculated by the model over the whole range of drying conditions.