Fabrication of magnetic porous Fe-Mn binary oxide nanowires with superior capability for removal of As(III) from water

Abstract

Magnetic porous Fe-Mn binary oxide nanowires were successfully fabricated to efficient removal of As(III) from water. The adsorption capacity of the porous nanowires for As(III) obviously increased with increasing of manganese oxide in the composite, accompanying decrease of the saturation magnetization of the adsorbents. Magnetic porous Fe-Mn binary oxide nanowires with an initial Fe:Mn molar ratio of 1:3 exhibited the highest absorption capacity for As(III) and enable magnetic separation from water. The maximal adsorption capacity value is 171mgg(-1) at pH 7.0. In the initial pH range from 3 to 9, 200μgL(-1) of As(III) could be easily decreased to below 10μgL(-1) by the magnetic porous Fe-Mn binary oxide nanowires (0.05gL(-1)) within 75min, and the corresponding residual As was completely oxidized to less toxic As(V). The coexisting chloride, nitrate and sulfate had no significant effect on arsenic removal, whereas, phosphate and humic acid reduced the removal of As(III) by competing with arsenic species for adsorption sites. The resulting magnetic porous Fe-Mn binary oxide nanowires could be a promising adsorbent for As(III) removal from water.

Keywords: Adsorption; As(III); Fe–Mn binary oxides; Magnetic porous nanowires; Oxidation.