文獻名：U (VI) sequestration by Al-rich minerals: Mechanism on phase dependence and the influence of natural organic matter

作者： Zequan Liu^ab，Tao Ou^ab，Minhua Su^ab，Hairong Peng^ab，Gang Song^ab，Lingjun Kong^ab，Diyun Chen^ab

^a School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China

^b Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China

摘要：Uranium and uranium-containing pollutants are excessively released into the environment, leading to serious water and soil contamination. Minerals such as alumina are naturally abundant and frequently affect the fate and migration behavior of uranium ions. A thorough understanding of the migration and immobilization behavior of uranium on Al-rich minerals (e.g., α-alumina [α-Al₂O₃] and γ-alumina [γ-Al₂O₃)]) is essential for unraveling numerous environmental issues. We performed a systematic comparative analysis of U(VI) retention by α-/γ-alumina. The effects of coexisting ions and natural organic matter were explored. Solution pH contributed critically to the retention of U(VI) by α-/γ-alumina. The adsorption rate of γ-Al₂O₃ for U(VI) removal was faster than that of α-Al₂O₃, reaching equilibrium within 15 min with a high removal efficiency of 94.43%. PO₄³⁻ ions significantly promoted U(VI) adsorption, especially for the case of α-Al₂O₃. The addition of phosphate resulted in a 15-fold enhancement in adsorption capacity. Humic acid promoted U(VI) removal by γ-Al₂O₃ under acidic conditions while strong inhibition on both α-Al₂O₃ and γ-Al₂O₃ in basic conditions. The removal mechanism of U(VI) by alumina is mainly ascribable to electrostatic interaction and surface complexation from various oxygenated functional groups. The present findings are pivotal to the understanding of uranium migration and immobilization in the environment.

關鍵詞：Adsorption；Alumina；Crystal structure；Humic acid；Uranium (VI)