Radionuclide contamination has become an urgent problem with the development of nuclear power plants. Herein, chemical-decorated core-shell magnetic manganese dioxide (denoted as Fe3O4@C@MnO2) composites were synthesized via transforming KMnO4 to MnO2 on the carbon-covered magnetite (Fe3O4@C) microsphere surface. It was employed to remove U(VI) and Eu(III) ions from aqueous solution under various conditions. The kinetic adsorption data were well simulated by the pseudo-second-order model and adsorption isotherms were fitted well by Langmuir model. Moreover, the maximum uptake capacities were up to 77.71 mg/g for U(VI) and 51.01 mg/g for Eu(III) at pH = 5.0 and T = 298 K. Adsorption behavior was strongly related to pH values but weakly affected by ionic strength, implying that the interaction of U(VI)/Eu(III) with Fe3O4@C@MnO2 was mainly dominated by inner-sphere surface complexation. XPS analysis illustrated that the interaction of Eu(III)/U(VI) with Fe3O4@C@MnO2 was associated with the strong metal bonds (MnO), hydroxyl bonded on metal (Mn-OH) and carboxyl groups (-COOH) by surface complexation and zeta potential results implied that the adsorption process was governed by electrostatic attraction. This research highlighted the outstanding performance of Fe3O4@C@MnO2 in eliminating Eu(III)/U(VI) ions from aqueous solutions, which was of great significance in the future application in radionuclides' pollution treatment.

中文翻译：

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制备核壳结构Fe3O4@C@MnO2纳米颗粒以有效消除 U（VI） 和 Eu（III） 离子


放射性核素污染已成为核电站发展的亟待解决的问题。在此，通过在碳覆盖的磁铁矿 （Fe3O4@C） 微球表面将 KMnO4 转化为 MnO2 合成了化学修饰的核壳磁性二氧化锰 （表示为 Fe3O4@C@MnO2） 复合材料。它用于在各种条件下从水溶液中去除 U（VI） 和 Eu（III） 离子。准二级模型对动力学吸附数据进行了较好的模拟，Langmuir 模型对吸附等温线进行了较好的拟合。此外，在 pH = 5.0 和 T = 298 K 时，U（VI） 和 Eu（III） 的最大吸收量高达 77.71 mg/g，Eu（III） 的最大吸收量高达 51.01 mg/g。吸附行为与 pH 值密切相关，但受离子强度的影响较弱，表明 U（VI）/Eu（III） 与 Fe3O4@C@MnO2 的相互作用主要以球内表面络合为主。XPS 分析表明，Eu（III）/U（VI） 与 Fe3O4@C@MnO2 的相互作用与强金属键 （MnO）、金属上的羟基键 （Mn-OH） 和羧基 （-COOH） 通过表面络合相关，zeta 电位结果表明吸附过程受静电吸引控制。本研究突出了 Fe3O4@C@MnO2 在去除水溶液中 Eu（III）/U（VI） 离子方面的出色性能，这对未来放射性核素污染处理的应用具有重要意义。