Enhancing the filtration performance and antifouling ability of polyethylenimine-based nanofiltration membranes by doping with polyethylene glycol derivatives

The low permeability and high fouling susceptibility of nanofiltration (NF) membranes limit their widespread application in water treatment. In this study, a polyethylenimine (PEI)-based NF membrane was synthesized via interfacial polymerization with a mixture of PEI and the polyethylene glycol derivative Jeffamine (JA) as the aqueous phase comonomer and trimesoyl chloride as the organic phase monomer. A 1/1 mass ratio of PEI to JA with a total aqueous phase monomer concentration of 1.00 % (weight/volume) yielded NF membranes with optimal water permeance and satisfactory salt exclusion. Compared with the pristine membrane, the JA-doped PEI-based (JA/PEI) membrane exhibited enhanced surface hydrophilicity, a more positively charged surface, an enlarged effective pore size, a thinner polyamide layer, and greater surface roughness. Furthermore, the optimal JA/PEI membrane was more resistant to protein fouling because of the lower adhesion energy between it and protein molecules. Additionally, the optimal JA/PEI membrane exhibited excellent permeation flux and comparable retention performance in the treatment of actual drinking water. This JA-doping strategy provides a facile avenue to fabricate NF membranes with higher permeability and better antifouling ability for water treatment applications.