In order to promote the application of membrane technology in the treatment of textile wastewater containing small molecule dye, fabricating a hollow fiber loose nanofiltration (LNF) with a thin and compact separation layer and deepening the understanding of compactness-tailoring mechanism in chemical crosslinking are essential. Firstly, the mechanisms of synergistic crosslinking of PEI-70K and PEI-10K, along with a weakening of the PEI hydration by ethanol, were expounded in primary crosslinking. Then, some LNF separation layers with different compactness were prepared through crosslinking with different crosslinkers to further reduce pore size, which resulted in the efficient removal (~100%) of a small molecular dye (methyl orange (MO), M=327 g mol^–1). The removal of methyl orange is mainly caused by size sieving. The relationship among the pore size, the M_w of the secondary crosslinkers, and the pore size reduction rate was interpreted by comparing the pore size reduction rate of three secondary crosslinkers with different molecular weights. In addition, the as-prepared separation layer exhibited excellent dimensional stability and solvent resistance. This paper not only provides a reference for fabricating hollow fiber LNF with better purification performance, but also shows their potential in developing solvent resistant nanofiltration

为了促进膜技术在处理含小分子染料的纺织废水中的应用，制造具有薄而致密的分离层的中空纤维松散纳滤（LNF）并加深对化学交联中致密性-剪裁机制的理解是必不可少的. 首先阐述了PEI-70K和PEI-10K协同交联以及乙醇对PEI水化作用减弱的作用机理。然后，通过用不同的交联剂交联制备一些具有不同致密性的 LNF 分离层以进一步减小孔径，从而有效去除（~100%）小分子染料（甲基橙（MO），M=327  g  mol ^–1）。甲基橙的去除主要是通过筛分引起的。通过比较三种不同分子量的二级交联剂的孔径减小率来解释孔径、二级交联剂的M _w和孔径减小率之间的关系。此外，所制备的分离层表现出优异的尺寸稳定性和耐溶剂性。本文不仅为制备具有更好净化性能的中空纤维LNF提供了参考，而且展示了它们在开发耐溶剂纳滤方面的潜力。