Assessment of the effect of kinetics on colloid facilitated radionuclide transport in porous media.

Binding of radionuclides to natural colloids can significantly alter their transport behaviour in porous media. Dependent on the interaction between radionuclides, colloids and the solid matrix, radionuclide transport may be enhanced or retarded as a result of the presence of colloids. Often, equilibrium models are used to describe interactions between radionuclides, colloids and the solid matrix. However, experimental results indicate that kinetic processes may be important. In this paper, a model for coupled colloid and radionuclide transport in porous media is presented. Kinetic relationships are incorporated for the interaction between radionuclides, colloids and solid matrix. With this transport model, column experiments have been simulated, and modelling results are compared with experimental data reported in literature. It appears that kinetic interaction relationships are required to adequately model the experimental data.