含酰腙基PolyDTH-400xCOF/CPAN复合纳滤膜的制备及染料分离性能

Preparation and dye separation performance of PolyDTH-400x COF/CPAN composite nanofiltration membrane containing acylhydrazone group

摘要:

PolyCOFs（聚合物共价有机骨架）是一种新的多孔共价有机框架材料，具有良好的结晶度和机械性能。本文合成了含有高分子链段结构聚乙二醇（PEG-400）的聚合物构筑单体（聚-2,5-聚乙二醇甲氧基对苯二甲酰肼）DTH-400，并采用2,5-二乙氧基对苯二甲酰肼(DTH)、DTH-400、三醛基间苯三酚 (Tp) 三组份界面聚合的方式，制备含有 PEG-400 链段的 PolyDTH-400x/CPAN （羧基化聚丙烯腈）复合膜，探究了 DTH-400 与 DTH 的添加比例对膜的孔径以及分离性能的影响。结果表明，高分子链的引入有效地缩小了共价有机框架材料（COF）分离层的孔径，同时高分子链段的引入提高了PolyDTH-400xCOF膜的结晶性能和机械性能，COF膜具有更好的力学和热稳定性。当 DTH-400 与 DTH 添加的物质的量之比为 1:2 时，制备的高分子聚合物膜 PolyDTH-4001/3/CPAN 性能最佳，对考马斯亮蓝-R250 的截留率大于 99%，纯水通量为 25.2 L/(m2·h·105pa)。

Abstract:

PolyCOFs (polymer covalent organic frameworks) is a new porous covalent organic framework material with good crystallinity and mechanical properties. In this paper, a polymer building monomer (poly-2,5-polyethylene glycol methoxy terephthaloyl hydrazide) DTH-400 containing polyethylene glycol (PEG-400) segment structure was synthesized. PolyDTH-400x/CPAN (carboxylated polyacrylonitrile) composite membrane containing PEG-400 segment was prepared by interfacial polymerization of 2,5-diethoxyterephthaloyl hydrazide (DTH), DTH-400 and trialdehyde phloroglucinol (Tp).The effects of the addition ratio of DTH-400 to DTH on the pore size and separation performance of the membrane were investigated. The results show that the introduction of polymer chains effectively reduces the pore size of the separation layer of covalent organic framework material (COF), and the introduction of polymer chains improves the crystallization and mechanical properties of PolyDTH-400x COF membrane. The COF membrane has better mechanical and thermal stability. When the molar ratio of DTH-400 to DTH was 1:2, the prepared polymer membrane PolyDTH-4001/3/CPAN had the best performance. The rejection rate of Coomassie brilliant blue-R250 was greater than 99 %, and the pure water flux was 25.2 L/(m2·h·105pa).