Adsorption of chromium(VI) by titanium(IV) oxide coated on a silica gel surface

Abstract

Titanium(IV) oxide, coated on the surface of silica gel (surface area, 308 m² g^–1; amount of Ti^IV per gram of modified silica gel, 1.8 × 10^–3 mol), was used to adsorb CrO₄^2– ions from acidic solutions. The exchange capacity increased at lower pH values and was affected to some extent by the acid used. The material was used to preconcentrate Cr^VI from 0.5 ppm solutions of chromate very efficiently and virtually 100% recovery was achieved in every instance.