Reducing the Pore Size of Covalent Organic Frameworks in Thin-Film Composite Membranes Enhances Solute Rejection
Reducing the Pore Size of Covalent Organic Frameworks in Thin-Film Composite Membranes Enhances Solute Rejection
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DOI：
10.1021/acsmaterialslett.9b00272
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发表时间：
2019-10-01
影响因子：
11.4
通讯作者：
Dichtel, William R.
中科院分区：
文献类型：
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作者：
Corcos, Amanda R.;Levato, Gabrielle A.;Dichtel, William R.
三个亚胺连接的共价有机框架（COF）薄膜作为活性层加入到分离的薄膜复合材料（TFC）膜中，并测试了它们拒绝有机污染物替代品和水中盐的能力。合成膜由聚丙烯腈（PAN）载体和TAPB-PDA-H、TAPB-PDA-Me或TAPB-PDA-Et COF薄膜组成。后两种COFs分别将每个平铺六边形的6个甲基和乙基取代基导入孔中，同时在整个系列中保持相同的拓扑结构。这些取代基减少了COF的有效孔径，与母体ttap - pda - h COF相比。TFC TAPB-PDA-Me膜比TFC TAPB-PDA-H膜对罗丹明- wt （R-WT）染料和NaCI的排斥效果更好，TFC TAPB-PDA-Et膜的总体排斥效果最好。用于分析这种渗透行为的溶液扩散模型表明，随着后续垂基团加入到COF孔内部，在拒绝方面存在系统差异。这些发现证明了通过在给定拓扑结构中系统地减小有效孔径来调整COF膜选择性的概念。
Three imine-linked covalent organic framework (COF) films are incorporated as active layers into separate thin-film composite (TFC) membranes and tested for their ability to reject an organic pollutant surrogate and salt from water. The synthesized membranes consist of a polyacrylonitrile (PAN) support and a TAPB-PDA-H, TAPB-PDA-Me, or TAPB-PDA-Et COF thin film. The latter two COFs direct six methyl and ethyl substituents per tiled hexagon into the pores, respectively, while maintaining the same topology across the series. These substituents decrease the effective pore size of the COF compared to the parent TAPB-PDA-H COF. The TFC TAPB-PDA-Me membrane rejects Rhodamine-WT (R-WT) dye and NaCI better than the TFC TAPB-PDA-H membrane, and the TFC TAPB-PDA-Et membrane exhibits the best rejection overall. The solution-diffusion model used to analyze this permeation behavior indicates that there is a systematic difference in rejection as subsequent pendant groups are added to the interior of the COF pores. These findings demonstrate the concept of tuning the selectivity of COF membranes by systematically reducing the effective pore size within a given topology.