Modeling of isothermal supersaturation of solutions in a porous medium: estimation of it’s possible degree

The phenomenon of isothermal supersaturation of solutions in a porous medium at ion exchange is studied on the basis of mathematical modeling. The phenomenon consists in the fact that the solution with concentration significantly higher than the maximal solubility of the substance is formed in the pores of sorbent and no precipitation occurs. The question of why sediment does not appear in the pores between the grains is investigated in the article. It is shown that the phenomenon under consideration can be explained by the effect of dynamic equilibrium between the association of condensed phase particles in the inner part of the pores, their diffusion, and decomposition near the surface of the sorbent grains caused by a change in potential. The degree of possible supersaturation of the solution is estimated depending on the process parameters. The proposed hypothesis is confirmed by quantitative studies using the available experimental data.