Sorption of Cr(III) on silica and aluminium oxide:: experiments and modelling

The surface complexation model presented in this paper yields good results in describing the acid-base behaviour of adsorbents as well as the sorption of Cr(III) from freshly prepared solutions. The reactions proposed and the surface reaction constants extracted from the fitting procedure can simulate experimental sorption trends over a wide range of pi-Is, initial chromium concentrations and concentrations of the background electrolyte. The position and shape of the adsorption edges measured from aged solutions differ to those of freshly prepared solutions. The ionic strength affects sorption from aged solutions more than sorption from fresh solutions. (C) 1999 Elsevier Science B.V. All rights reserved.