The effect of polymer and silicate content on the effective diffusion coefficient, break-through time and specific ion retention was studied. It was found that the diffusion coefficient decreases, while the break-through time and ion retention increases with the solid content of gel. The relative effect of polymer is, however, an order of magnitude greater than that of the silicate content. The influence of gel components can be interpreted by a diffusion model elaborated for porous systems. Accordingly, the effect of polymer and silicate might the explained through their contribution to modification of the volume fraction of water in the gel and the tortuosity. It was definitely shown that the polymer concentration is mostly effective in increasing the tortuosity, while in the case of the silicate content both factors must be considered. As far as the practical application of the polymer/silicate gel is concerned it was concluded that the diffusion flux should be controlled primary by the macromolecular component of the searing or blocking phase.
