Modelling of cation concentrations in outflow of NaNO3 percolation experiments through Boom Clay cores

Experimental data is acquired on elution of some exchangeable cations from Boom Clay core by injection of NaNO3 solution. It is desirable to explain the observed elution curve using geochemical coupled modelling taking into account solute transport and water-clay interaction mechanisms. This report describes the modelling of Na+, K+, Ca2+, Mg2+ and Sr2+ concentrations in the outflow of the NaNO3 percolation experiments. The modelling is preliminary and in terms of chemical interactions only cation exchange processes are taken into account. The objective of the modelling is to test the applicability of the existing cation exchange models and parameters to prediction of percolation experiments. Potential application of the modelling results is to estimate the extent of Boom Clay, e.g., in terms of thickness, disturbed by NaNO3 plume in a longer time scale as compared to the percolation experiments.