Nano-structured magnetic chitosan microspheres(Fe3O4@CS) were synthesized by a facile solvothermal method. The microspheres were characterized. The results show that the Fe3O4@CS microspheres are 220–250 nm in diameter with a high saturation magnetization(i.e., > 38.5 A·m2/kg). The magnetic saturation and mono-dispersity decrease with the increase of chitosan content in the as-prepared samples. The adsorption behavior of the Fe3O4@CS microspheres for Hg2+ was investigated. The results reveal that the maximu...