▎ 摘　　要

Graphene oxide (GO) wrapped Fe3O4 nanoparticles (NPs) were prepared by coating the Fe3O4 NPs with a SiO2 layer, and then modifying by amino groups, which interact with the GO nanosheets to form covalent bonding. The SiO2 coating layer plays a key role in integrating the magnetic nanoparticles with the GO nanosheets. The effect of the amount of SiO2 on the morphology, structure, adsorption, and regenerability of the composites was studied in detail. An appropriate SiO2 layer can effectively induce the GO nanosheets to completely wrap the Fe3O4 NPs, forming a core-shell Fe3O4@SiO2@GO composite where Fe3O4@SiO2 NPs are firmly encapsulated by GO nanosheets. The optimized Fe3O4@SiO2@GO sample exhibits a high saturated adsorption capacity of 253 mg center dot g(-1) Pb(II) cations from wastewater, and the adsorption process is well fitted by Langmuir adsorption model. Notably, the composite displays excellent regeneration, maintaining a similar to 90% adsorption capacity for five cycles, while other samples decrease their adsorption capacity rapidly. This work provides a theoretical guidance to improve the regeneration of the GO-based adsorbents.