Diffusion and diffusion-convection experiments for studying the sorption of radionuclides in soils

Abstract

Diffusion experiments have been established as a convenient laboratory technique for studying sorption of radionuclides in soils. The through-diffusion technique was modified to allow for a constant pressure gradient over the soil pellet during the experiment. The design enables to choose various values of the Peclet number which reflect the relative contributions of convective and diffusive transport. For these experimental conditions, analytical solutions of the convection-dispersion equation are presented assuming a linear equilibrium sorption isotherm. Data are presented for diffusion and for diffusion-convection experiments of cesium using a parabrown earth.