Rapid and selective removal of trace As(III) from water using FeMn binary oxide

The rapid removal of trace arsenic is crucial for ensuring the safety of drinking water. However, achieving the rapid removal of trace arsenic poses a significant challenge. In this study, we aim to enhance the removal efficiency of trace arsenic by increasing the specific surface area of the adsorbent material while maintaining its micrometer size. The material design allowed for the rapid removal of trace amounts of As(III) in groundwater within 10 s, resulting in a concentration as low as 0.281 μg L^-1, which meets the WHO drinking water standard (<10 μg L^-1). Our experimental results demonstrated that the FeMn binary oxide could partially oxidize As(III) into As(V), achieving a removal efficiency exceeding 99 %. Furthermore, we investigated the influence of common cations and anions, such as K⁺, Mg²⁺, Ca²⁺, Cl^-, NO₃^-, SO₄^2-, and PO₄^3-, which may be present in natural water, on As(III) removal. Our findings indicated that the FeMn binary oxide exhibited remarkably high separation factors (ranging from 10 to 10³) for other coexisting ions, indicating its exceptional selectivity for As(III) even in the presence of other ions. The outstanding arsenic uptake capability and selectivity of the FeMn binary oxide make it a highly promising adsorbent for the efficient removal of trace As(III) from aqueous solutions.