ION SORPTION ON MODIFIED SILICA SURFACE

The experimental data for Cu2+ ion sorption on four samples of aminopropylsilica are presented. From these data it is shown that, at small degrees of filling, Cu2+ ion forms a complex with two grafted ligands. With an increase in the degree of filling a transition to the preferential formation of complexes with the composition 1:1 takes place. Methods for calculation of the corresponding stability constants are proposed. Using the lattice model of ion sorption by grafted ligands the isotherm equation was obtained, which takes into account the possibility of stepwise complex formation as well as the influence of ligand protonization. It is shown that this equation describes quite well the experimental data on Cu2+ sorption by aminopropylsilica. © 1990.