Se(IV) sorption on TiO2: Sorption kinetics and surface complexation modeling

The sorption of Se(IV) on TiO2 (anatase) was investigated as functions of contact time, pH, ionic strength, solid-to-liquid ratio (m/V) and Se(IV) concentration by using a batch sorption method. It was found that the sorption kinetics of Se(IV) can be described by a pseudo-second-order model. Both the amount of Se(IV) sorbed at equilibrium and the pH of aqueous solution affect the rate constant of Se(IV) sorption on anatase. The results at sorption equilibrium indicate that Se(IV) sorption is pH-dependent and insensitive to ionic strength. A constant capacitance model was used to quantitatively interpret Se(IV) sorption on anatase. Inner-sphere surface complexes, SSeO3− and S2SeO3, were considered.