Efficient uranium adsorption performance of TiO2 nanoparticles through the bridging effect of SiO2 and the high selectivity of amidoxime

In this work, a SiO 2 -doped and amidoxime-grafted TiO 2 -based material was synthesized, exhibiting high uranium adsorption performance due to the bridging effect of SiO 2 and the high selectivity of the amidoxime group. The successful preparation of modified materials has been validated by means of modern analytical testing techniques (scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and X-ray diffraction). In the adsorption experiment, the TiO 2 -based material exhibited a maximum adsorption capacity of 648.4 mg/g within 90 min at pH = 5 and the adsorption efficiency attained 99.1% under low-concentration conditions (C 0  = 10 mg/L). The high efficiency adsorption for U(VI) on the TiO 2 -based material could be attributed to the strong synergistic complexation of -OH and amidoxime groups with U(VI). Meanwhile, the adsorption process was also contributed by redox reaction, electrostatic attraction and the transport of interlayer bound water. Overall, the SiO 2 -doped and amidoxime-grafted TiO 2 -based material exhibited superior adsorption performance, positioning it as a promising adsorbent for the treatment of U(VI)-containing wastewater.