Recent research has focused on the acid resistance of polyamide nanofiltration (NF) membranes, a critical aspect for their stability during practical applications. However, the impact of different acids, particularly the role of various anions, on NF membrane acid resistance remains unexplored. Our research systematically evaluates NF membrane performance and property alterations under various acids at identical pH levels, supplemented by density functional theory (DFT) simulations. Results reveal that membranes treated with H₃PO₄ retain desirable NF performance, in stark contrast to those treated with H₂SO₄ and HCl, which undergo significant degradation. Specifically, H₃PO₄-treated membranes showed only a 4.2 % decline in Na₂SO₄ rejection, compared to a dramatic 83.3 % decline for HCl-treated membranes under identical pH. This degradation is linked to the acids infiltrating the polyamide structure. The membrane's enhanced resistance to H₃PO₄ is primarily due to the strong negative charge of phosphate ions, influenced by the Donnan effect, which prevents deep penetration into the membrane. This is further supported by DFT simulations, which reveal that the interaction energy between the membrane surface and phosphate ions is over twice as high as with chlorine ions, highlighting the importance of ion-specific interactions. This research highlights the crucial role of anions in acidic environments for the maintenance and operation of NF membranes in industrial applications. It provides key insights for enhancing membrane efficiency and longevity under acidic conditions.

最近的研究重点是聚酰胺纳滤（NF）膜的耐酸性，这是其在实际应用中稳定性的一个关键方面。然而，不同酸，特别是各种阴离子的作用，对纳滤膜耐酸性的影响仍有待探索。我们的研究系统地评估了纳滤膜在相同 pH 水平下的各种酸下的性能和性质变化，并辅以密度泛函理论 (DFT) 模拟。结果表明，用 H3PO4 处理的膜保留了理想的 NF 性能，这与用 H2SO4 和 HCl 处理的膜形成鲜明对比，后者发生了显着的降解。具体而言，在相同 pH 值下，经 H₃PO4 处理的膜对 Na2SO4 的截留率仅下降 4.2%，而经 HCl 处理的膜截留率则大幅下降 83.3%。这种降解与渗透聚酰胺结构的酸有关。膜对 H₃PO₄ 的增强抵抗力主要是由于磷酸盐离子的强负电荷，受唐南效应的影响，从而阻止了深入渗透到膜中。DFT 模拟进一步支持了这一点，该模拟表明膜表面与磷酸根离子之间的相互作用能是氯离子的两倍以上，凸显了离子特异性相互作用的重要性。这项研究强调了酸性环境中阴离子对于工业应用中纳滤膜的维护和运行的关键作用。它为提高酸性条件下的膜效率和寿命提供了重要见解。