Abstract Nanofiltration (NF) membranes with both high permeability and salt rejection are in dire need for water treatment. Generally, heat treatment is an essential step for fabricating polyamide NF membranes. Conventional heat treatment in an oven causes membrane pore shrinkage and over cross-linking, which often leads to a severe loss of permeation performance. Herein, we report a single-step method by heat-treating membranes in non-neutral solutions to avoid pore shrinkage and generate graded hydrolysis in membrane selective layer. As confirmed by the XPS result, the polyamide NF membrane fabricated via controlled hydrolysis possesses a gradient cross-linking degree vertically along the membrane surface. This optimal polyamide NF membrane had a superior pure water permeability (PWP) of 27.5 L m−2 h−1 bar−1 and high Na2SO4 rejection of 98.5%. Such controlled hydrolysis approach provides novel strategy for fabricating high performance polyamide membranes.

中文翻译：

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通过受控水解制备具有梯度交联选择性层的高级纳滤膜

摘要 具有高渗透性和盐截留率的纳滤 (NF) 膜是水处理的迫切需要。通常，热处理是制造聚酰胺 NF 膜的必要步骤。烘箱中的常规热处理会导致膜孔收缩和过度交联，这通常会导致渗透性能严重下降。在此，我们报告了一种通过在非中性溶液中热处理膜以避免孔收缩并在膜选择性层中产生分级水解的单步方法。XPS 结果证实，通过受控水解制备的聚酰胺 NF 膜具有沿膜表面垂直的梯度交联度。这种最佳聚酰胺 NF 膜具有 27.5 L m-2 h-1 bar-1 的优异纯水渗透率 (PWP) 和 98.5% 的高 Na2SO4 截留率。