Kinetics and Equilibrium of Cadmium Complexation with Heterogeneous Complexants: A Stopped-Flow Study at Na-Illite

Sorption equilibrium and kinetics of NpO2+on dispersed particles of Na-montmorillonite

“…We fitted the Langmuir-Freundlich type equation [3] to the experimental results by considering the heterogeneous surface of the Na-montmorillonite…”

“…The mean affinity coefficients and the heterogeneity coefficients were evaluated as log K m = 4.5 ± 0.1 and β = 0.83 ± 0.03 for NpO 2 + . The corresponding affinity spectrum is given as [3,4] …”

“…(iii) The electrostatic potential is altered by the complexation in the neighborhood of the binding site and thereby influences its behavior. (iv) The site density at natural minerals is not uniform but varies over the surface [2][3][4].…”

“…Pohlmeier has proposed a new method to discuss the sorption of metal ions on the heterogeneous surface [2][3][4]. His basic idea is that binding sites on homologous complexants (like humic acid or suspended colloidal particles) are heterogeneous.…”

“…In the present work, the equilibrium and kinetics of sorption of NpO 2 + on a Na-montmorillonite from Japan are investigated by the experimental methods proposed by Pohlmeier [2][3][4], and the influence of heterogeneity of the Na-montmorillonite surface on the sorption of NpO 2 + is discussed. We used montmorillonite, because montmorillonite is not only a major component of bentonite that is used in the engineered barrier of multi-barrier systems for waste disposal, but also one of the typical inorganic groundwater colloids.…”