Loose nanofiltration (LNF) membranes with a molecular weight cut-off (MWCO) of about 1000 Da and high surface negative charge density have great application potential for drinking water treatment pursuing high rejection selectivity between natural organic matter (NOM) and mineral salts. This study was conducted to exploit the novel method coupling non-solvent induced phase separation (NIPS) and interfacial polymerization (IP) for the preparation of high-performance LNF membranes. A number of LNF membranes were synthesized by varying the polyethersulfone (PES) and piperazine (PIP) concentrations in the cast solution for the PES support layer preparation. Results showed that these two conditions could greatly affect the membrane water permeance, MWCO and surface charge. One LNF membrane, with a water permeance as high as 23.0 ± 1.8 L/m²/h/bar, when used for the filtration of conventional process-treated natural water, demonstrated a rejection of NOM higher than 70% and a low rejection of mineral salts at about 20%. Both the mineral salts/NOM selectivity and permselectivity were superior to the currently available LNF membranes as far as the authors know. This study demonstrated the great advantage of the NIPS–IP method for the fabrication of LNF membranes, particularly for the advanced treatment of drinking water.

中文翻译：

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用于饮用水处理的天然有机物和盐类具有高排斥选择性的松散纳滤膜的制备

截留分子量 (MWCO) 约为 1000 Da 和高表面负电荷密度的松散纳滤 (LNF) 膜在追求天然有机物 (NOM) 和矿物盐之间的高截留选择性的饮用水处理方面具有巨大的应用潜力。本研究旨在利用将非溶剂诱导相分离 (NIPS) 和界面聚合 (IP) 相结合的新方法制备高性能 LNF 膜。通过改变用于 PES 支撑层制备的浇铸溶液中的聚醚砜 (PES) 和哌嗪 (PIP) 浓度来合成许多 LNF 膜。结果表明，这两个条件会极大地影响膜透水性、MWCO和表面电荷。一层 LNF 膜，透水率高达 23.0 ± 1.8 L/m² /h/bar，当用于过滤传统工艺处理的天然水时，表明 NOM 的截留率高于 70%，而矿物盐的截留率低，约为 20%。据作者所知，矿物盐/NOM 选择性和渗透选择性均优于目前可用的 LNF 膜。这项研究证明了 NIPS-IP 方法在制造 LNF 膜方面的巨大优势，特别是在饮用水的深度处理方面。