Membranes with sub-10-nm pores are receiving growing interest in recognizing and separating nanocolloids, biomolecules, and soluble salts from water, but suffer from difficulty of optimizing pore structures and inferior stability. Herein, we report an efficient method for the preparation of robust nanoporous phenolic membranes with widely tunable pore sizes in the range of nanofiltration and tight-ultrafiltration. Solutions of resol precursors and poly(ethylene glycol)s (PEGs) are spin-coated to form thin films and then heated to thermopolymerize resols into phenolics. Subsequently, the films are treated in H₂SO₄ solution to degrade PEGs, producing nanoporous phenolic membranes. Thus-prepared phenolic membranes exhibit adjustable effective pore sizes and tunable separation performances from nanofiltration to tight-ultrafiltration, which is otherwise inaccessible. Due to the thin thicknesses and rich water channels, the membranes exhibit higher permeances than other tight-ultrafiltration membranes and commercial ultrafiltration membranes with similar rejections. Furthermore, thanks to the robust frameworks and good chemical resistance of phenolics, the membranes deliver stable performances in long-term operations, elevated pressures, and acidic conditions. This work provides a facile and universal strategy for the synthesis of membranes with sub-10-nm pores for nanofiltration and tight-ultrafiltration.

具有亚 10 纳米孔的膜在识别和分离水中的纳米胶体、生物分子和可溶性盐方面越来越受到关注，但存在优化孔结构困难和稳定性差的问题。在此，我们报告了一种制备坚固的纳米多孔酚醛膜的有效方法，该膜具有在纳滤和紧密超滤范围内广泛可调的孔径。酚醛树脂前体和聚（乙二醇）（PEG）的溶液被旋涂以形成薄膜，然后加热使酚醛树脂热聚合成酚醛树脂。随后，薄膜在 H ₂ SO ₄中处理降解 PEG 的溶液，产生纳米多孔酚醛膜。如此制备的酚醛膜表现出可调节的有效孔径和从纳滤到紧密超滤的可调分离性能，否则这是无法实现的。由于较薄的厚度和丰富的水通道，该膜比其他紧密超滤膜和具有类似截留率的商用超滤膜具有更高的渗透性。此外，由于酚醛树脂的坚固框架和良好的耐化学性，膜在长期运行、高压和酸性条件下提供稳定的性能。这项工作为合成具有亚 10 纳米孔的膜提供了一种简便而通用的策略，用于纳滤和紧密超滤。