Abstract:The development of highly efficient uranium adsorption materials is of great significance to the environmental safety of abandoned uranium mines and tailings pond leachate with ultra-low concentrations of uranium contamination. In this study, a three-dimensional fluffy SiO2 nanofiber membrane (SiO2-NFM) was directly synthesized by one-step electrospinning process through the controlled hydrolysis of tetraethyl orthosilicate (TEOS). Subsequently, the SiO2-NFM was used as the substrate to prepare amidoxime-functionalized silica nanofiber membranes (SiO2-AO NFM) by the hydroxylamine hydrochloride reduction of cyano groups. The morphology, structure, and composition of SiO2-AO NFM were analyzed by SEM, EDS, and FTIR, and the uranium adsorption performance was studied through adsorption experiments. The results show that the amidoxime groups were successfully modified on the surface of SiO2 nanofiber membrane, exhibiting the best adsorption performance at pH value of 6 and temperature of 35 ℃, reaching equilibrium in 30 minutes. The adsorption process follows the pseudo-second-order kinetic model and the Langmuir model, with a theoretical maximum adsorption capacity of 32.12 mg/g at a uranium concentration of 10 mg/g and 26.05 mg/g at 5 mg/L. When applied to the actual tailings leachate with a concentration of 5.56 mg/L, the adsorption capacity reaches 23.3 mg/g. The SiO2-AO NFM shows good selectivity for uranium adsorption with removal rate of up to 99% in the first cycle, and it still maintains 76% of its adsorption performance after six cycles of regeneration.