Cationic covalent organic framework for efficient removal of PFOA substitutes from aqueous solution
Cationic covalent organic framework for efficient removal of PFOA substitutes from aqueous solution
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DOI：
10.1016/j.cej.2020.127509
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发表时间：
2020-10
影响因子：
15.1
通讯作者：
Wei Wang;Ziming Zhou;Haipei Shao;Shuangxi Zhou;Gang Yu;S. Deng
中科院分区：
文献类型：
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作者：
Wei Wang;Ziming Zhou;Haipei Shao;Shuangxi Zhou;Gang Yu;S. Deng
全氟辛酸(PFOA)替代品如六氟环氧丙烷二聚酸(GenX)和六氟环氧丙烷三聚酸(HFPO-TA)是有毒的环境污染物，需要有效的吸附剂将其从水中去除。在这项研究中，通过亚胺缩合反应开发了一种新型的阳离子共价有机骨架(COF)，可以有效地去除水溶液中的GenX和HFPO-TA。所制备的碳纤维为AA堆积的二维六方有序结构，具有中孔和微孔两种类型。季铵盐的引入对COF的形貌和晶体结构影响不大。季铵盐型阳离子COF对GenX和HFPO-TA的吸附容量分别为2.06和2.16 mm ol/g，均高于传统的活性碳和树脂。考察了pH值和天然有机物对COF中GenX和HFPO-TA的去除效果的影响。有趣的是，之前吸附在阳离子COF上的GenX被长链HFPO-TA取代，通过密度泛函理论计算进一步阐明了潜在的竞争机理。这项研究通过拓扑结构设计突出了COFS在有效去除水溶液中的全氟烷基和多氟烷基物质方面的特殊潜力。
Perfluorooctanoic acid (PFOA) substitutes such as hexafluoropropylene oxide dimer acid (GenX) and hexafluoropropylene oxide trimer acid (HFPO-TA) are toxic as environmental contaminants, and efficient adsorbents are required to remove them from waters. In this study, the novel cationic covalent organic framework (COF) was developedviaan imine condensation reaction for efficient removal of GenX and HFPO-TA from aqueous solution. The prepared COFs exhibited a 2D ordering hexagonal structure with AA stacking and two classes of pores (mesopore and micropore). The introduction of quaternary ammonium on COF exhibited little effect on its morphology and crystal structure. The cationic COF with quaternary ammonium showed high adsorption capacity for GenX (2.06 mmol/g) and HFPO-TA (2.16 mmol/g), more efficient than conventional activated carbons and resins. The effects of pH and natural organic matter on the removal efficiency of GenX and HFPO-TA on COF were also investigated. Interestingly, the previously adsorbed GenX on the cationic COF was replaced by the longer-chain HFPO-TA, and the underlying competitive mechanism was further clarified by performing a density functional theory calculation. This study highlights the exceptional potential of COFs through topology structural design for the efficient removal of per- and polyfluoroalkyl substances from aqueous solution.