Rapid and effective removal of arsenite from water using a novel oxidation-sorption bifunctional MOF

Water purification from highly migratory and toxic As(III) is challenging but critically needed. Herein, a novel oxidation-sorption bifunctional UiO-66-Cl was fabricated by replacing some organic linkers in UiO-66 with oxidation groups (N-chlorosulfonamide) and applied for deep purification of As(III) contamination. In UiO-66-Cl, oxidation groups are closely distributed around the sorption sites achieving rapid capture of As(III) after oxidation. UiO-66-Cl1:5 achieved decontamination of As(III) level (1035 μg/L) to meet the drinking standard level (less than 10 μg/L) in just 10 min. Similar removal efficiencies can be achieved across a very broad pH range (3–10), which is superior to most other sorbents. Moreover, aqueous disturbances, such as the coexistence of common anions and natural organic matter, hardly affected As(III) removal by UiO-66-Cl1:5. UiO-66-Cl1:5 could still perform reliably in natural water matrixes. During the removal process, the majority of As(III) was oxidized to As(V) and captured through an inner-sphere complexing mechanism. The exhausted UiO-66-Cl1:5 could be effectively regenerated by treatment with NaOH solution and NaClO solution. The work provided a versatile MOFs-based sorbent for reliable and simple remediation of As(III) contamination.