Characterization of the diffusion and reaction properties of dissolved Si in pore water

Abstract

Through-diffusion experiment comparing the diffusivity of Si, K, and Cl in sandstone revealed that the diffusion of Si in pore water was slower than predicted from the diffusion coefficients (D₀) of Si, K, and Cl in bulk water. Additionally, centrifugal extraction of pore water initially having a Si concentration of 1.7 mM revealed that Si concentration was decreased by precipitation. The results suggested that Si diffusion was retarded by the change of concentration profile in the rock due to precipitation and by the decrease of D₀ of Si due to change of dissolved state of Si such as polymerization.