Abstract
Since colloidal particles in soils are known to act as a carrier of contaminants, understanding the transport behavior of colloidal particles in the soil is an important issue. This study investigates the transport behavior of colloidal particles during the cation exchange reaction between Ca2+ and Na+ at the surface of porous media. One-dimensional column experiments were conducted using Toyoura sand as the repacked porous media and carboxyl latex particles as the model colloid, respectively. It was found that colloidal particles deposited on the surface of the Toyoura sand during the cation exchange reaction, regardless of the amount of exchanged cation and the particle size of the applied colloids. The deposited colloidal particles were released when the ionic strength of the pore water decreased after the cation exchange reaction. The interaction energies between the latex particles and the sand surface were calculated based on the DLVO theory, suggesting the contribution of the attraction in the secondary minimum to the colloid deposition during cation exchange reaction.
https://ror.org/057zh3y96 
