Removal of arsenic(v) from aqueous solutions using sulfur-doped Fe 3 O 4 nanoparticles.

In this study, magnetic sulfur-doped Fe 3 O 4 nanoparticles (Fe 3 O 4 :S NPs) were applied as adsorbents for the removal of As(v). Fe 3 O 4 :S NPs were fabricated by a two-step route, which included low-temperature mixing and high-temperature sintering. The as-prepared Fe 3 O 4 :S NPs could effectively remove As(v) under a wide pH range of 2-10 and presented a high As(v) adsorption capacity of 58.38 mg g -1 , which was much better than undoped Fe 3 O 4 nanoparticles (20.24 mg g -1 ). Adsorption experiments exhibited a pseudo-second-order model of adsorption kinetics and a Langmuir isotherm model of adsorption isotherms. Additionally, the coexisting ions such as NO 3 - , SO 4 2- , and CO 3 2- had no significant effect on As(v) adsorption and the adsorbent worked well in actual smelting wastewater. XPS and FTIR spectra of Fe 3 O 4 :S NPs before and after As(v) adsorption showed that Fe-OH groups played a significant role in the adsorption mechanisms. Moreover, the magnetic Fe 3 O 4 :S NPs adsorbents after adsorption could be rapidly separated from wastewater with an external magnetic field. Therefore, Fe 3 O 4 :S NPs could be an ideal candidate for the removal of As(v) from water.