Effect of cluster formation of dissolved Si on diffusion rate

Abstract

According to known diffusion coefficients of Si, K, Cl in bulk water [D_0,K ≈ D_0,Cl = 1.7 × D_0,Si], diffusion rate of Si was expected to be ~1.7 times as large as those of K and Cl. However, through diffusion experiment for measuring diffusion rates of K, Cl, Si in rock pore water showed that Si diffused slower than expected from the difference of D₀ values. Based on MD simulation for evaluating the concentration dependence of Si, K, Cl on diffusivity, the slow diffusion of Si is likely to be due to cluster formation of Si.