کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6466153 | 1422953 | 2017 | 12 صفحه PDF | دانلود رایگان |
- Defective TiO2âx with abundant oxygen vacancies were fabricated.
- TiO2âx can simultaneous remove U(VI) and HA from aqueous solutions.
- The sorption capacities of U(VI) and HA on TiO2âx at pH = 5.0 were 65 and 142 mg gâ1, respectively.
- The presence of HA enhanced U(VI) sorption on TiO2âx, the surface adsorbed U(VI) also enhanced HA sorption.
- The oxygen vacancies could provide high chemical activity to trap U(VI) in the defective sites.
In this paper, the defective TiO2âx with abundant oxygen vacancies were fabricated through a simple modified solvothermal strategy and characterized by SEM, TEM, XRD, FT-IR, EDX, Zeta-potential, and XPS techniques in detail. The prepared TiO2âx was applied to remove U(VI) and humic acid (HA) from aqueous solutions to evaluate its sorption performance. The sorption of U(VI) and HA on TiO2âx was examined under various environmental conditions (e.g., contact time, pH, ionic strength, initial HA/U(VI) concentrations, the addition sequences of HA/U(VI) and temperature). According to the Langmuir model simulation, the maximum sorption capacities of U(VI) and HA on TiO2âx at pH = 5.0 were calculated to be 65 and 142 mg gâ1, respectively, which were higher than most current reported materials. The kinetic results indicated that the sorption of U(VI) and HA onto TiO2âx was better described by the pseudo-second-order kinetic model. The presence of HA enhanced U(VI) sorption on TiO2âx at pH = 5.0, meanwhile, the surface adsorbed U(VI) on TiO2âx also enhanced the sorption capacity of HA, which was mainly attributed to the formation of U(VI)-HA-TiO2âx ternary complexes. Combining FT-IR and XPS analysis, the oxygen vacancies could provide high chemical activity and trap U(VI) in the defective sites of TiO2âx, while the sorption of HA was dominated by surface complexation. The findings might provide an opportunity to estimate and optimize the efficient simultaneous elimination of radionuclides and natural organic substances by using defective TiO2âx.
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Journal: Chemical Engineering Journal - Volume 325, 1 October 2017, Pages 576-587