Eutrophication of water bodies caused by the excessive phosphate discharge has constituted a serious threat on a global scale. It is imperative to exploit new advanced materials featuring abundant binding sites and high affinity to achieve highly efficient and specific capture of phosphate from polluted waters. Herein, water stable Zr-based metal organic frameworks (MOFs, UiO-66) with rational structural design and size modulation have been successfully synthesized based on a simple solvothermal method for effective phosphate remediation. Impressively, the size of the resulting UiO-66 particles can be effectively adjusted by simply altering reaction time and the amount of acetic acid with the purpose of understanding the crucial effect of structural design on the phosphate capture performance. Representatively, UiO-66 particles with small size demonstrates 415 mg/g of phosphate uptake capacity, outperforming most of the previously reported phosphate adsorbents. Meanwhile, the developed absorbents can rapidly reduce highly concentrated phosphate to below the permitted level in drinking water within a few minutes. More significantly, the current absorbents display remarkable phosphate sorption selectivity against the common interfering ions, which can be attributed to strong affinity between Zr-OH groups in UiO-66 and phosphate species. Furthermore, the spent UiO-66 particles can be readily regenerated and reused for multiple sorption-desorption cycles without obvious decrease in removal performance, rendering them promising sustainable materials. Hence, the developed UiO-66 adsorbents hold significant prospects for phosphate sequestration to mitigate the increasingly eutrophic problems.

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The rational design of metal-organic frameworks with tailored components and structural features is crucial for achieving the desired functions and expanding the emerging applications. Herein, water-stable bimetallic Fe/Mg metal−organic frameworks (Fe/Mg-MIL-88B) have been successfully fabricated through a facile and effective one-step strategy to access the exceptional arsenic decontamination. Notably, the obtained bimetallic Fe/Mg-MIL-88B architectures are demonstrated to possess a well-defined spindle-like morphology. Interestingly, the Fe/Mg molar ratios within the resultant Fe/Mg-MIL-88B frameworks can be flexibly modulated on demand, leading to the variation of the structural features associated with length/diameter ratio and unit cell parameters along with surface areas. Thanks to the unique structural and compositional merits as well as the synergetic contribution from two active metal centres, the fabricated Fe/Mg-MIL-88B nanospindles exhibit enhanced decontaminant performance toward arsenate in terms of ultrafast sorption kinetics and high sorption capacities, compared to the monometallic Fe-MIL-88B.