MOF材料在水环境污染物去除方面的应用现状及发展趋势(II)

Review on the application of MOF materials for removal of pollutants from the water (II)

  • 摘要: 对近年来MOF材料去除水环境中重金属、有机物的相关研究进行了总结与评述。本篇是该主题的第2篇,主要对MOF材料去除水中有机污染物的相关研究进行总结和论述。研究表明,MOF材料含有大量开放性金属位点、路易斯酸碱位以及官能团,因而对染料、抗生素、农药、持久性有机污染物等均具有较高的吸附性能。氢键、π‒π作用、疏水作用和静电引力是其吸附有机污染物的主要机制,部分MOF材料中较大的孔道结构也有利于大分子有机污染物的吸附;另外,部分MOF材料还具有优异的催化性能,能够作为类Fenton催化,光催化以及过硫酸盐活化的催化剂实现对有机污染物的催化降解,其中光催化反应中污染物的降解主要源于·O2−、·OH和h+的贡献;而在过硫酸盐体系中,·O2−、·OH、SO4·−1O2是导致有机污染物分解的主要活性氧化物种。基于对先前研究的回顾,相信未来的研究领域包括但不限于以下方面:(1)进一步提高MOF在去除有机污染物方面的性能,并提高其可回收性;(2)开展新型MOF催化材料的制备及催化反应机理的研究;(3)研究MOF缺陷结构的调控,以开发具有更高吸附和催化性能的新型MOF材料;(4)研究新的框架材料,例如共价有机骨架(COFs)材料,并将其应用于污染物净化领域。

     

    Abstract: Metal–organic frameworks (MOFs) are a class of organic–inorganic hybrid functional materials generally formed via self-assembly of metal ions or metal clusters and rigid organic ligands with nitrogen and oxygen atoms. The wide range of potential applications of MOF materials includes gas storage and separation, catalysis, sensing, and drug transportation and release, which can be attributed to their versatile designable structures, modifiable chemical functionality, low-density framework, large specific surface area, and functional and permanent pore space. MOF and its composite materials have also been employed to remove various contaminants from the environment in the recent decade. To present the remarkable research progress and outcomes of MOF materials in the removal of pollutants from the water environment, the related studies on the removal of heavy metals and organic pollutants from the water environment were reviewed in this paper. This was the second paper on the topic that mainly introduced the research progress of MOF materials in the removal of organic pollutants in aqueous solution. The previous studies have shown that MOF materials have open metal sites and Lewis acid–base sites; thus, they exhibit a high adsorption performance for dyes, antibiotics, pesticides, and persistent organic pollutants. Hydrogen bonding, π–π interaction, hydrophobic interaction, and electrostatic attraction are the main mechanisms for their adsorption of organic pollutants. In addition, the large pore structure of some MOF materials is conducive to the adsorption of macromolecular organic pollutants. Moreover, some MOF materials that can be used as catalysts for Fenton-like reactions, photocatalytic reactions, and persulfate activation to degrade organic pollutants, exhibit excellent catalytic performance. The degradation of pollutants in photocatalytic reactions can be mainly attributed to the contributions of ·O2−, ·OH, and h+. In the persulfate system, ·O2−, ·OH, SO4·−, and 1O2 are the main reactive oxide species that cause the decomposition of organic pollutants. Based on the review of previous studies, it is believed that future research will include but will not be limited to the following: (1) the improvement of the performance of MOF in removing organic pollutants and its recyclability; (2) the preparation of new MOF catalytic materials and investigation of catalytic reaction mechanisms; (3) the regulation of the defect structure of MOF to develop new MOF materials with high adsorption and catalytic efficiency; and (4) the analysis of new framework materials, e.g., covalent organic framework materials, and their applications in the field of pollutant purification.

     

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