Predictive Model for Migration of Metallic Cations in Natural Sediments

Recently, a sorption model based on ion exchange equilibria was proposed and successfully applied to predict the sorption behavior of metallic cations in natural sediments under batch conditions [1]. In the present study, this sorption model is coupled with a 1-D transport simulation code to check its validity under dynamic conditions. Therefore, reactive transport experiments of major cations (Ca, Na) using a natural sediment column were studied in the laboratory. A comparison between experimental and predicted breakthrough curves is reported. Results show that the sorption model coupled with the transport code is able to predict with good confidence the migration of major cations in a natural sediment. The participation of protons in the ion exchange process was confirmed by the variation of the experimental pH, coinciding with the modelʹs prediction.