Abstract A simple strategy is proposed for high performance polyimide nanofiltration (PI-NF) membranes by optimization of a synergistic imidization reaction. Soluble poly(amic acid) polymers with partial imidization was successfully controlled and fabricated by chemical imidization. With the product as a matrix, NF membranes with an integrally skinned asymmetric architecture were obtained by phase inversion and subsequent thermal imidization. The brittle and ruptured defects caused by directly high temperature conversion for fabricating PI-NF membranes were effectively avoided. The prepared membrane showed high rejections for dye, PEG and typical salts. The fabricated PI-NF membranes were endowed with a high permeance of isopropyl alcohol [approximately 1 L/(m2 h bar)] and a high rejection of rose Bengal (greater than 92%). The molecular weight cut-off of PI-NF membrane is below 800 Da. The pure water flux of PI-NF membrane prepared under optimized conditions was approximately 20 L/(m2 h) and the rejection for Na2SO4 was 93.91% at 5 bar. The rejection for different salts followed the order: Na2SO4 > MgSO4 > NaCl > MgCl2, revealed that Donnan exclusion theory and steric hindrance effect dominated the rejection mechanism. Furthermore, the NF membranes showed excellent stability over a long-term filtration process.

中文翻译：

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通过优化协同酰亚胺化，具有高选择性和性能稳定性的带负电荷的聚酰亚胺纳滤膜

摘要 通过优化协同酰亚胺化反应，提出了一种用于高性能聚酰亚胺纳滤 (PI-NF) 膜的简单策略。通过化学酰亚胺化成功控制和制备了部分酰亚胺化的可溶性聚（酰胺酸）聚合物。以该产品为基质，通过相转化和随后的热酰亚胺化获得具有整体表皮不对称结构的 NF 膜。有效避免了直接高温转化制备PI-NF膜造成的脆裂缺陷。制备的膜显示出对染料、PEG 和典型盐的高截留率。制造的 PI-NF 膜具有异丙醇的高渗透率 [约 1 L/(m2 h bar)] 和对孟加拉玫瑰的高截留率（大于 92%）。PI-NF 膜的截留分子量低于 800 Da。在优化条件下制备的 PI-NF 膜的纯水通量约为 20 L/(m2 h)，在 5 bar 下对 Na2SO4 的截留率为 93.91%。不同盐类的排斥顺序为：Na2SO4>MgSO4>NaCl>MgCl2，表明Donnan排斥理论和空间位阻效应主导了排斥机制。此外，NF 膜在长期过滤过程中表现出优异的稳定性。揭示唐南排斥理论和空间位阻效应主导了排斥机制。此外，NF 膜在长期过滤过程中表现出优异的稳定性。揭示唐南排斥理论和空间位阻效应主导了排斥机制。此外，NF 膜在长期过滤过程中表现出优异的稳定性。