Iron Mesh-Based Metal Organic Framework Filter for Efficient Arsenic Removal

Efficient oxidation from arsenite [As(III)] to arsenate [As(V)], which is less toxic and more readily to be adsorbed by adsorbents, is important for the remediation of arsenic pollution. In this paper, we report a metal organic framework (MIL-100(Fe)) filter to efficiently remove arsenic from synthetic groundwater. With commercially available iron mesh as a substrate, MIL-100(Fe) is implanted through an in situ growth method. MIL-100(Fe) is able to capture As(III) due to its microporous structure, superior surface area, and ample active sites for As adsorption. This approach increases the localized As concentration around the filter, where Fenton-like reactions are initiated by the Fe²⁺/Fe³⁺ sites within the MIL-100(Fe) framework to oxidize As(III) to As(V). The mechanism was confirmed by colorimetric detection of H₂O₂, fluorescence, and electron paramagnetic resonance detection of ·OH. With the aid of oxygen bubbling and Joule heating, the removal efficiency of As(III) can be further boosted. The MIL-100(Fe)-based filter also exhibits satisfactory structural stability and recyclability. Notably, the adsorption capacity of the filter can be regenerated satisfactorily. Our results demonstrate the potential of this filter for the efficient remediation of As contamination in groundwater.