[Xiang, Renjun; Wen, Tao; Xie, Lixia; Zhong, Yu; Cheng, Yingxiang; Zhao, Yuanyuan; Liu, Zhan; Xu, Youze; Fu, Guangyi] Key Laboratory of Water Pollution Control Technology, Hunan Research Academy of Environmental Sciences, Changsha, 410004, China
[Liu, Xingqun] Institute of Urban Construction, University of South China, Hengyang, 421001, China
[Xie, Lixia] State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
[Zhong, Y; Xiang, RJ] Hunan Res Acad Environm Sci, Key Lab Water Pollut Control Technol, Changsha 410004, Hunan, Peoples R China.
project of the International Science & Technology Cooperation Program of China [2013DFG91190]; Natural Science Foundation of Hunan Province [2017JJ3148]
Fe(II)-Al(III) layered double hydroxides (Fe-Al LDHs) were prepared by the sono-assisted precipitation method and used for the removal of uranium (VI) from aqueous solutions. The application of ultrasound in the Fe-Al LDHs preparation promoted the formation of the hydrotalcite-like phase and improved the adsorption capacity of U(VI). Batch experiments were carried out to investigate the influence of solid-to-solution ratio, initial U(VI) concentration, initial pH, contact time and temperature on the U(VI) removal process. The experimental results indicated that the removal process of U(VI) could be well described by the pseudo-second-order kinetic model. The equilibrium isotherm for U(VI) removal was fitted by the Langmuir model and the maximum adsorption capacity of Fe-Al LDHs was 113.64 mg/g at a temperature of 308 K. The thermodynamic parameters implied that the removal of U(VI) was essentially an endothermic process. The FT-IR, EDX and XPS results suggested that the removal mechanism involves combined adsorption-reduction processes. When the U(VI) ions absorbed onto the Fe-Al LDHs through physical adsorption, the Fe(II) in the structure of Fe-Al LDHs reduces U(VI) to U(IV) while Fe(II) was oxidized to Fe(III). (C) 2017 Elsevier B.V. All rights reserved.