Study of uranyl sorption onto hematite by in situ attenuated total reflection-infrared spectroscopy

In this paper, we present results of ATR-IR spectroscopy of uranyl complexes adsorbed on hematite. This method allowed the in situ recording of infrared spectra of uranyl sorbed on hematite in presence of aqueous solution and to detect one peak at 906 cm(-1) attributed to the antisymmetric O=U=O stretching. The intensity of the peak increases with pH, but its shape does not evolve, indicating that the same surface species is responsible for the sorption in the pH range 5-8. The reversibility experiments confirm that the hematite deposit reacts in the same way as dispersed suspensions. Measurement of the stretching frequency of nitrate ions coming from electrolyte showed a pure electrostatic adsorption and exclude the formation of a ternary complex with uranyl.