The identification of FeS2 as a sorption sink for Tc(IV)

In [Maes, A., Bruggeman, C., Geraedts, K., Vancluysen, J., 2003. Quantification of the interaction of Tc with dissolved boom clay humic substances. Environ. Sci. Technol., 37, 747–753] the interaction of Tc(IV) with dissolved boom clay humic substances was quantified by the interpretation of the solid–liquid distribution of Tc in boom clay batch suspensions using a modified Schubert approach. During this procedure it was established that multiple sorption sinks for Tc(IV) were present within the boom clay. By combining different initial Tc concentrations and different added amounts of ground FeS2 to a boom clay suspension at a single solid-to-liquid ratio, the same Schubert approach was used here to identify FeS2 as one of the sorption sinks present within the boom clay. The amount of Tc(IV) adsorbed by FeS2 could be described by a simple Langmuir adsorption isotherm. The interaction of Tc(IV) with dissolved boom clay humic substances in these systems was also investigated and could be quantified by an identical interaction constant (logKTcO(OH)2=5.30)(logKTcO(OH)2=5.30) as the one calculated in Maes et al. (2003).