Heterogeneous Sorption of Radionuclides Predicted by Crystal Surface Nanoroughness.

Reactive transport modeling (RTM) is an essential tool for the prediction of contaminants' behavior in the bio- and geosphere. However, RTM of sorption reactions is constrained by the reactive surface site assessment. The reactive site density variability of the crystal surface nanotopography provides an "energetic landscape", responsible for heterogeneous sorption efficiency, not covered in current RTM approaches.

Effects of surface roughness and mineralogy on the sorption of Cm(III) on crystalline rock.

Crystalline rock is one of the host rocks considered for a future deep geological repository for highly active radiotoxic nuclear waste. The safety assessment requires reliable information on the retention behavior of minor actinides. In this work, we applied various spatially resolved techniques to investigate the sorption of Curium onto crystalline rock (granite, gneiss) thin sections from Eibenstock, Germany and Bukov, Czech Republic.

Molecular-Level Speciation of Eu(III) Adsorbed on a Migmatized Gneiss As Determined Using μTRLFS.

The interaction of Eu(III) with thin sections of migmatized gneiss from the Bukov Underground Research Facility (URF), Czech Republic, was characterized by microfocus time-resolved laser-induced luminescence spectroscopy (μTRLFS) with a spatial resolution of ∼20 μm, well below typical grain sizes of the material. By this approach, sorption processes can be characterized on the molecular level while maintaining the relationship of the speciation with mineralogy and topography. The sample mineralogy was characterized by powder X-ray diffraction and Raman microscopy, and the sorption was independently quantified by autoradiography using Eu.

Technetium retention by gamma alumina nanoparticles and the effect of sorbed Fe.

Technetium (Tc) retention on gamma alumina nanoparticles (γ-AlO NPs) has been studied in the absence (binary system) and presence (ternary system) of previously sorbed Fe as a reducing agent. In the binary system, γ-AlO NPs sorb up to 6.5% of Tc from solution as Tc(VII).

Sorption of Eu(III) on Eibenstock granite studied by µTRLFS: A novel spatially-resolved luminescence-spectroscopic technique.

In this study a novel technique, micro-focus time-resolved laser-induced luminescence spectroscopy (µTRLFS) is presented to investigate heterogeneous systems like granite (mainly consisting of quartz, feldspar, and mica), regarding their sorption behavior. µTRLFS is a spatially-resolved upgrade of conventional TRLFS, which allows point-by-point analysis of single minerals by reducing the beam size of the analytic laser beam to below the size of mineral grains. This provides visualization of sorption capacity as well as speciation of a luminescent probe, here Eu.