Spinel-type ferrite nanoparticles for removal of arsenic(V) from water

Spinel ferrite particles (Fe₃O₄, MnFe₂O₄, and CoFe₂O₄) were investigated as magnetic nanosorbents for removing arsenic from spiked water samples. The nanosorbents were collected via magnetic separation from aqueous solutions spiked with an arsenic concentration that mimics the amount of this contaminant in real water samples. This research shows that using amounts of CoFe₂O₄ or MnFe₂O₄ as low as 40 mg/L, the arsenic content in the contaminated water decreased for levels below the maximum admitted value by the World Health Organization for drinking waters (10 μg/L). Moreover, these magnetic nanosorbents also showed good performance for As(V) sorption, when applied to aqueous matrices with variable ionic strength and in the mixtures of other several hazardous contaminants. The good performance observed for the MnFe₂O₄ and CoFe₂O₄ ferrites contrasts with the one observed for Fe₃O₄ nanosorbent, whose efficiency is lower in the removal of As(V) from water, nevertheless increased with the presence of other elements in solution.