School of Environmental Science and Engineering, State Key Laboratory of Bio-fibers and Eco-textiles, Collaborative In-novation Center for Marine Biomass Fibers, Qingdao University, Qingdao 266071, PR China.
Institute of Coastal Environmental Pollution Control, Ministry of Education Key Laboratory of Marine Environment and Ecology, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266100, PR China.
J Hazard Mater. 2022 Feb 15;424(Pt D):127715. doi: 10.1016/j.jhazmat.2021.127715. Epub 2021 Nov 12.
Selective immobilization of SeO is highly desired for the remediation of Se-contaminated water. Thus, the irreversible sorption of SeO ions by adsorbents through unique coordination bonds with high affinity is needed. Herein, we demonstrated that Fe-based metal-organic framework (MOF) (Fe-MIL-101) with free coordination sites (FCSs) enabled selective and irreversible capture of SeO ions from aqueous solution with fast kinetics and a high uptake capacity of 183.7 mg∙g, owing to large MOF apertures and substantial numbers of FCSs as capture sites through forming Fe-O-Se bonds. Meanwhile, Fe-MIL-101 maintained excellent performance in a broad pH range (4-11) and high selectivity for SeO ions in the presence of excessive competitive anions (e.g., CO, PO). Density functional theory (DFT) calculation, extended X-ray absorption fine structure (EXAFS), and Mössbauer fittings confirmed that the capture on Fe-MIL-101 was through the Fe-O-Se coordination bonds between FCSs and SeO. Moreover, Fe-MIL-101 could effectively remove SeO in simulated natural water and sewage by overcoming the influence of co-existing ions and organic matters. This study highlights new opportunities for the design of MOF-based materials for removing toxic and radioactive anions with irreversibility and high selectivity from natural and waste water.
从受污染的水中去除硒通常需要将硒（SeO）选择性地固定下来。因此，需要通过与高亲和力的独特配位键不可逆地将硒（SeO）离子吸附到吸附剂上。在此，我们证明了具有游离配位位（FCS）的基于铁的金属有机骨架（MOF）（Fe-MIL-101）能够从水溶液中快速动力学选择性地不可逆地捕获硒（SeO）离子，并且具有 183.7mg·g 的高吸附容量，这归因于大的 MOF 孔径和大量的 FCS 作为通过形成 Fe-O-Se 键的捕获位点。同时，在存在大量竞争阴离子（例如 CO 和 PO）时，Fe-MIL-101 在宽 pH 范围（4-11）内仍保持出色的性能和对 SeO 离子的高选择性。密度泛函理论（DFT）计算、扩展 X 射线吸收精细结构（EXAFS）和穆斯堡尔拟合证实，在 FCS 和 SeO 之间形成的 Fe-O-Se 配位键是 Fe-MIL-101 捕获 SeO 的方式。此外，Fe-MIL-101 可以有效地从模拟天然水和污水中去除 SeO，克服了共存离子和有机物的影响。这项研究为设计基于 MOF 的材料提供了新的机会，可用于从天然和废水中去除具有不可逆性和高选择性的有毒和放射性阴离子。
