Abstract Intraparticle diffusion of Cs + and Sr 2+ cations in rocks has been studied using crushed rock samples. The batch adsorption technique has been employed with varying temperatures ranging between 5° and 60°C with an initial solution of concentration of 10 ppm. The results indicate that intraparticle diffusion coefficients for both cations were in the range of 10 −8–10 −7 cm 2s −1 and these could be classified into two competitive processes: surface and pore diffusion processes. The results suggest the critical concentration at which the surface diffusion dominates is ∼2 ppm for Sr 2+. The apparent activation energies of the surface diffusion coefficients for a granite sample are 10.2 and 5.0 kcal. mol −1 for Cs + and Sr 2+, respectively. The value is twice as large as that of the apparent diffusion coefficient for Cs + and is larger by ∼20% for Sr 2+. This implies the major role of the surface diffusion in the case of the solution concentration exceeding a few ppm range.