Modification of the characteristics of polymeric membranes is regarded as an alternative to control the flux decline caused by the concentration polarization and the fouling in ultrafiltration (UF). This work investigated the use of dopamine (DA) and polyethyleneimine (PEI) to hydrophilize the surface and to improve the performance of a 50 kDa polyethersulfone UF membrane. The hydraulic permeance of membranes was investigated for the membranes modified using a DA solution with its concentration fixed at 2 mg·mL^-1 and a PEI solution with its concentration varying from 0 to 16 mg·mL^-1. The membrane modified in a 16 mg·mL^-1 solution of PEI presented the uppermost hydraulic permeance (33 L·h-1·m^-2). This membrane and two other controls (unmodified and modified membranes with a 2 mg·mL^-1 solution of DA) were further characterized for surface chemistry using Fourier transform infrared by attenuated reflectance (FTIR-ATR) and X-ray excited photoelectron spectroscopy (XPS) charge (zeta potential), morphology (field emission scanning electron microscopy (FESEM) and optical interferometry), water mass gain, and performance in bovine serum albumin (BSA) UF. XPS showed an increase in the nitrogen content and a decrease in the sulfur content indicating the membrane modification. Membrane modification with DA/PEI caused an increase in hydrophilicity, which could reduce the interaction of BSA with the membrane surface. The flux of protein solutions was improved by 400%, and there was a complete recovery of the water flux after chemical cleaning of the modified membrane.

改变聚合物膜的特性被认为是控制通量下降的一种替代方法，该通量下降是由浓度极化和超滤（UF）结垢引起的。这项工作研究了使用多巴胺（DA）和聚乙烯亚胺（PEI）亲水化表面并改善50 kDa聚醚砜UF膜的性能。研究了用浓度固定在2 mg·mL ^-1的DA溶液和浓度在0至16 mg·mL ^-1的PEI溶液改性的膜的水膜渗透性。在16 mg·mL ^-1的PEI溶液中改性的膜表现出最高的水力渗透性（33 L·h-1·m ^-2）。该膜和其他两个对照（未修饰的和修饰的膜，其浓度为2 mg·mL ^-1通过衰减反射（FTIR-ATR）和X射线激发光电子能谱（XPS）电荷（zeta电位），形态学（场发射扫描电子显微镜（FESEM）和光学干涉法），水量增加和牛血清白蛋白（BSA）超滤性能。XPS显示氮含量增加而硫含量减少，表明膜发生了改性。用DA / PEI进行的膜修饰导致亲水性增加，这可能会减少BSA与膜表面的相互作用。蛋白质溶液的通量提高了400％，化学清洗改性膜后，水通量得到了完全恢复。