Multifunction adsorption materials: Part 1-Interaction of uranium and crystalline TiO₂.mH₂O modified by amorphous SiO₂.nH₂O

Abstract

The crystalline hydrous titanium dioxide modified by amorphous hydrous silicon dioxide (CTDASD), 2SiO₂.3Ti O₂.6H₂O has been synthesized by ageing the amorphous mixed silicon-titanium hydroxide at 80°C for 36 hours. The prepared material possesses adjustable selectivity and apparent ion exchange capacity for a certain element or even for a group of elements. XRD, TGA and pH titration have been employed to characterize the prepared material. The uptake of uranyl ions on CTDASD is independent of concentration of sodium ions under the experimental conditions investigated, suggesting the material synthesized is reliable to remove uranyl ions from the media of high salt concentration. The uptake of uranium on the CTDASD is remarkably sensitive to the solution pH and reaches the maximum at pH 4.5. Plot of log <em>K_D </em>of uranium versus equilibrium pH generates a series of lines with the mean slope of 0.63 at pH 1,→ 4, indicating the sophisticated loading mechanisms in H / UO²⁺₂ reaction.