Lacunary polyoxometalate @ ZIF for ultradeep Pb(II) adsorption

Lacunary polyoxometalates (LPOMs), showing merits of designable coordination sites, may offer tremendous potential in toxic Pb(II) capture. However, their utilization is limited by their solubility in water and difficulty in reuse. Here, we report a self-assemble strategy to encapsulate LPOMs in customized cavities of ZIFs to afford reusable LPOM@ZIF adsorbents, with vacant oxygen sites tuned to afford efficient Pb(II) adsorption. It exhibited outstanding capture capacity of 764 mg g −1 , extraordinary affinity with K d of 2.87 × 10 7 mg L −1 , and ultrarapid efficiency with h of 412.5 mg g −1 min −1 that could enable ultradeep water purification from 71770 ppb to 1.84 ppb within 15 min. Density functional theory calculation and experiments validated the contribution of oxygen in LPOMs on this impressive Pb(II) adsorption followed μ 1 O >  μ 2 O >  μ 3 O, and NH on ZIFs was another site. Outcomes thus reveal LPOM@ZIF is an appealing platform for ultradeep Pb(II) removal that could address the most urgent global health challenges.