The sea urchin magnetic nano-Fe3O4@TiO2 particles (SUMNPs) with core-shell structure were prepared by sol-gel technique combined with hydrothermal method. The morphologies and surface areas of SUMNPs were characterized by methods such as TEM and SEM. It was confirmed that the sea-urchin magnetic nanomaterial exhibit Fe3O4 microsphere as core and TiO2 as shell

the diameter of the particles is about 400 nm

the specific surface area is 236.082 m2·g-1

and the surface pore size is about 6.274 nm. The adsorption on heavy metal ions showed that

based on the Pb2+ ion radius is large and the layers of elections is more

in the mixed system of Pb2+

Cd2+

Cu2+

Zn2+ and Ni2+

SUMNPs could adsorb Pb2+ with high capacity and high selectivity

and almost no adsorption of other four heavy metal ions. The single Pb2+ adsorption could be fast equilibrium in 5 min and the equilibrium adsorption capacity was 283 mg·g-1. The adsorption process is in accordance with the Langmuir isothermal adsorption model

and the saturated adsorption capacity is up to 458.72 mg·g-1. After desorbed and regenerated by EDTA disodium and NaOH

SUMNPs can be reused more than 8 times. In summary

SUMNPs have excellent selectivity for Pb2+

and have good application prospect in the treatment of pollution and restoration of water ecological environment.