Electron spectroscopy for chemical analysis investigation of the interaction of uranyl and calcium ions with humic acids

摘要

Surface complexes of uranyl and calcium ions with solid humic acid were studied by electron spectroscopy for chemical analysis (ESCA). Uranyl-, calcium-, and mixed uranyl-calcium-humates were prepared. The uranium and calcium concentrations were determined both in the bulk and at the surface of the humates. The atomic ratio U/Ca is larger at the surface than in the bulk. The interatomic distances (U-O)(ax) and (U-O)(eq) around the uranium atom in humates were determined. The differences in the concentration of functional groups and in complexation are discussed for two types of humic acid. (C) 1998 Elsevier Science S.A. All rights reserved. [References: 6]