金属有机框架材料对Cr(Ⅵ)离子的吸附去除研究进展

Recent Advances in Adsorptive Removal ofCr(Ⅵ)Ions by Metal‑Organic Frameworks

重金属离子污染问题一直备受关注。开发利用多孔材料吸附去除水中重金属离子一直是材料、环境等相关学科领域的研究热点之一。金属有机框架材料(metal⁃organic frameworks,MOFs)是一类新型的多孔材料,具有结构多样、比表面积大、孔径可调、孔表面特征易设计调控等特点,在气体分离、催化、传感等领域表现出极大的应用潜力。近年来,高稳定MOF材料的构筑取得了许多重大突破,大量研究工作探索了这类材料在水中的应用,包括水中重金属离子的吸附去除。Cr(Ⅵ)离子是一类毒性大、分布广的重金属离子,不同条件下存在形态多样,其吸附去除研究具有理论和实际意义。本文主要综述了近年来利用MOF材料吸附去除水中Cr(Ⅵ)离子的研究工作,并将这些材料归属为:(1)高稳定的锆基MOF、(2)阳离子框架型MOF、(3)后修饰的MOF及(4)MOF基复合材料4类;也对这些材料的Cr(Ⅵ)离子吸附机理、吸附量、材料再生性等进行了概括;最后分析了MOF材料在重金属离子吸附去除实际应用上存在的问题并展望了今后的重点研究方向。

The pollution of heavy metal ions has long been a big concern to the society.The development and utiliza⁃tion of porous materials for the adsorptive removal of heavy metal ions in water represents one of the hottest research subjects in related areas,such as materials science and environmental science.Due to their structural variety,large specific surface area,adjustable pore size,and tailorable pore surface characteristics,metal⁃organic frameworks(MOFs)show great potential in many applications,such as gas separation,catalysis,and sensing.In the past few years,many major breakthroughs have been made in the construction of highly stable MOFs.A lot of research works have been explored for the applications of MOFs in water systems,including the adsorptive removal of heavy metal ions in water.Cr(Ⅵ)ions are a kind of wide⁃distributed heavy metal ions with high toxicity,existing in water in vari⁃ous forms under different conditions.The study on the removal of Cr(Ⅵ)ions from water is of significance academical⁃ly and practically.Herein,the published research works about adsorptive removal of Cr(Ⅵ)ions with MOFs or MOF⁃based materials are reviewed.These materials are classified into four classes:(1)highly stable zirconium⁃based MOF,(2)cationic MOF,(3)post⁃modified MOF,and(4)MOF⁃based composite materials.The adsorption mecha⁃nism,adsorption capacity,and regenerability of these materials for Cr(Ⅵ)ions are also discussed.The existing prob⁃lems and the trend of future works for the practical application of MOFs in the removal of heavy metal ions are ana⁃lyzed at last.