Synthesis of novel magnetic sulfur-doped FeOnanoparticles for efficient removal of Pb（Ⅱ）

In this work, we report the synthesis of magnetic sulfur-doped Fe3O4 nanoparticles （Fe3O4:S NPs） with a novel simple strategy,which includes low temperature multicomponent mixing and high temperature sintering. The prepared Fe3O4:S NPs exhibit a much better adsorption performance towards Pb（Ⅱ） than bare Fe3O4 nanoparticles. FTIR, XPS, and XRD analyses suggested that the removal mechanisms of Pb（Ⅱ） by Fe3O4:S NPs were associated with the process of precipitation （formation of PbS）, hydrolysis,and surface adsorption. The kinetic studies showed that the adsorption data were described well by a pseudo second-order kinetic model, and the adsorption isotherms could be presented by Freundlich isotherm model. Moreover, the adsorption was not significantly affected by the coexisting ions, and the adsorbent could be easily separated from water by an external magnetic field after Pb（Ⅱ） adsorption. Thus, Fe3O4:S NPs are supposed to be a good adsorbents for Pb（Ⅱ） ions in environmental remediation.