Salt accumulation is inevitable in the conventional textile wastewater treatment, which hardly realize the effectively remove of dye and recover of water. Loose nanofiltration (NF) membrane with highly hydrophilic surface and loose structure has been demonstrated as an optimal choice for efficient dye/salt separation. This study develops a loose NF membrane via the layer-by-layer (LbL) assembly of highly-branched sulfonated polyethyleneimine (SPEI)/polyethyleneimine (PEI) and mussel-inspired post-crosslinking. Different molecular weights of highly-branched SPEI are synthesized. Effects of LbL assembly and cross-linking process, SPEI molecular weight and crosslinker type are investigated systematically. It is found that the membrane prepared with the assembly of SPEI10k/PEI and crosslinked by catechol exhibits low roughness (Ra = 3.56 nm), high hydrophilicity (WCA = 44.07°) and negatively-charged membrane surface (ζ = −16.39 mV). As a result, the membrane achieves an ultrahigh permeability (~ 36.89 LMH/bar), excellent dyes retention (> 99.37% to Congo red), as well as low rejection to salts (2.47% to NaCl). The novel loose NF membrane developed in this work therefore shows a promising prospect in practical industrial textile wastewater treatment.

传统的纺织废水处理中不可避免地会出现盐分的积累，很难实现染料的有效去除和水的回收。具有高度亲水表面和松散结构的松散纳滤 (NF) 膜已被证明是有效分离染料/盐的最佳选择。本研究通过高度支化的磺化聚乙烯亚胺 (SPEI)/聚乙烯亚胺 (PEI) 和受贻贝启发的后交联的逐层 (LbL) 组装开发了一种松散的 NF 膜。合成了不同分子量的高度支化的 SPEI。系统地研究了 LbL 组装和交联过程、SPEI 分子量和交联剂类型的影响。发现用 SPEI10k/PEI 组装制备并由邻苯二酚交联的膜表现出低粗糙度（Ra = 3.56 nm），高亲水性 (WCA = 44.07°) 和带负电荷的膜表面 (ζ = -16.39 mV)。因此，该膜实现了超高渗透率（~ 36.89 LMH/bar）、出色的染料保留（> 99.37% 刚果红）以及低盐截留率（2.47% NaCl）。因此，在这项工作中开发的新型松散 NF 膜在实际工业纺织废水处理中显示出广阔的前景。