Removal of cadmium and lead ions from water by sulfonated magnetic nanoparticle adsorbents.

A new adsorbent, Fe3O4 sulfonated magnetic nanoparticle (Fe3O4-SO3H MNP), was developed for heavy metal ions removal from water, which could be effectively separated from the solution owing to the superparamagnetic property. The nanoparticles can be used to remove heavy metal ions due to the additional active site, "sulfo-group", introduced by the AMPS branches grafted onto the iron oxide. The as-synthesized materials were characterized by SEM, TEM, FT-IR and BET. The FTIR, XPS and Zeta potential were used to describe the adsorption mechanism. The Fe3O4-SO3H MNPs showed rapid removal for Pb2+ and Cd2+ with maximum of adsorption capacity of 108. 93 and 80.9mg/g at 25°C, respectively. The adsorption isotherms for Pb2+ and Cd2+ fitted better with Langmuir than Freundlich models, indicated that the processes of the removal of Pb2+ and Cd2+ could follow a kind of similar adsorption manner. The adsorption kinetic was consistent with pseudo-second-order model. Furthermore, the reuse experiments results showed the adsorbent might have potential in treating heavy metal ions pollution in water.