Adsorption of Thallium(I) Ions on Titania Particle Surfaces in Aqueous Media

Abstract

A description is given of the modification of the adsorption of Tl(I) on a titania (Degussa P-25) surface by the presence of organic or inorganic co-additives in aqueous suspensions. The addition of oxalate, formate, acetate and phosphate anions (the latter at low levels below ~0.03 M) increased Tl(I) adsorption while the phosphate anion (at levels > ~0.03 M) inhibited Tl(I) adsorption. A surface complexation model comprising the titania surface sites, the anchor co-additives and bound Tl(I) species was invoked to explain the adsorption enhancement observed. The data presented build upon and complement those acquired earlier showing how metal ion adsorption on a TiO 2 surface is strongly influenced by co-additives in the aqueous medium.