The problems of poly(piperazineamide)-based thin film composite (TFC) nanofiltration (NF) membrane are the fouling, scaling and poor separation performance of uncharged organics and heavy metal ions. Permanent surface modification lowers the fouling/scaling problems. However, these problems persist as the separation progresses. We address these issues by the on-demand regenerable planting of polyethyleneimine (PEI) into the polyamide (PA) layer of TFC NF membrane. The regenerable planting is based on the electrostatic interaction among the protonated amine groups of low molecular weight PEI and ionized carboxylic acid groups situated at the relatively inner sites (low dielectric constant) of the PA network. The incorporated PEI chains are stable at the pH range of 3–9. The PEI incorporated membrane exhibits significantly enhanced antifouling/antiscaling property, rejection of heavy metal ions (98–99%) and bisphenol A (BPA, 95%) without much negatively affecting the bivalent anion rejection (Na₂SO_4, 97.5%) and water permeance (11 L m⁻² h⁻¹ bar⁻¹) as compared to the pristine and commercial membranes (55–82%, 50–76% and 98–99% rejections of heavy metal ions, BPA and Na₂SO₄). Advantageously, PEI chains are removable at pH ≤ 2 or pH ≥ 9.5 without affecting the main PA layer. The multiple removal and re-generation of the membrane have been achieved. The flux recovery of the membrane after antifouling/antiscaling tests significantly improved upon intentional removal and reincorporation of PEI. Inherent properties of the modified membrane channels couple with the on-demand regenerable ability show immense promises of the membrane in the separation applications.

聚哌嗪酰胺基薄膜复合（TFC）纳滤（NF）膜存在的问题是结垢、结垢以及对不带电有机物和重金属离子的分离性能差。永久性表面改性可减少结垢/结垢问题。然而，随着分离的进展，这些问题仍然存在。我们通过按需将可再生聚乙烯亚胺 (PEI) 植入TFC 纳滤膜的聚酰胺 (PA) 层来解决这些问题。可再生种植是基于低分子量PEI的质子化胺基团和位于PA网络相对内部位置（低介电常数）的电离羧酸基团之间的静电相互作用掺入的 PEI 链在 pH 值 3-9 范围内稳定。掺有 PEI 的膜具有显着增强的防污/防垢性能，对重金属离子 (98–99%) 和双酚 A (BPA, 95%) 的截留率没有太大负面影响，对二价阴离子的截留率 (Na₂SO_4,97.5%) 和与原始膜和商用膜相比，水渗透性（11 L m⁻² h⁻¹bar⁻¹₂SO₄）。有利的是，PEI链在pH≤2或pH≥9.5时可去除，而不影响主PA层。实现了膜的多次去除和再生。有意去除并重新掺入 PEI 后，防污/防垢测试后膜的通量恢复显着改善。改性膜通道的固有特性与按需再生能力相结合，显示出膜在分离应用中的巨大前景。