Abstract:During the mining, smelting and application of rare earths, a large amount of industrial wastewater containing low-concentration rare earth ions is inevitably produced. The efficient separation and recovery of valuable rare earth elements from such wastewater is of great significance. In this paper, Fe3O4@SiO2@P507 magnetic nanoparticles with excellent adsorption performance were successfully prepared. The effects of adsorption time, initial pH of the solution, solid-liquid ratio, initial Er(Ⅲ) concentration and temperature on the adsorption performance of Er(Ⅲ) were systematically investigated. The results show that under the conditions of 120 min adsorption time, initial pH of 6, solid-liquid ratio of 2 g/L, initial Er(Ⅲ) concentration of 100 mg/L and temperature of 298 K, Fe3O4@SiO2@P507 exhibits the best adsorption performance, with an adsorption capacity of about 40 mg/g and an adsorption rate of over 96%. In addition, the saturated adsorption material was desorbed with 1.5 mol/L HCl. After five cycles of desorption experiments, Fe3O4@SiO2@P507 still maintained high stability, and its removal rate of Er(Ⅲ) could still reach over 75%. The materials before and after adsorption were characterized by FT-IR, SEM, EDS, BET, etc., and the adsorption mechanism was explored. The results show that the adsorption process of Fe3O4@SiO2@P507 for Er(Ⅲ) is mainly dominated by the pore effect of P507, with electrostatic adsorption and chemical adsorption as auxiliary. The above results provides a new method for the efficient separation and recovery of low-concentration rare earthelements in aqueous solutions.

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