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

Abstract

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.