Interaction of Latex colloids with Grimsel Granodiorite and its component Minerals

A. Filby¹, M. Plaschke¹, H. Geckeis¹, Th. Fanghänel²

¹Institut für Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640,

D-76021 Karlsruhe, Germany

²European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany

Abstract

Interaction of carboxylated fluorescent latex colloids with natural Grimsel granodiorite and some of its component minerals is studied by fluorescence microscopy. The experiments are carried out by varying the pH from 2-10 at constant ionic strength. In general, strong adsorption is observed at pH values close to or below the expected pH_pzc of the mineral surface. In addition, the influence of Eu(III) on colloid adorption is investigated. Depending on pH a significant increase of colloid adsorption is observed with relatively high Eu(III) concentrations, whereas comparatively lower Eu(III) concentrations have no obvious effect on colloid adsorption neither on single minerals nor on the Grimsel granodiorite.

Keywords: Fluorescence microscopy; Latex colloids; Grimsel granodiorite, Adsorption