Sustainable polyester loose nanofiltration membranes from bio-derived monomers and cellulose supports for efficient dye/salt separation

Abstract

Thin-film composite (TFC) membranes are essential in water treatment, yet their fabrication often relies on toxic solvents (e.g., N-methyl-2-pyrrolidone, dimethylformamide, n-hexane) and petroleum-derived polymers (e.g., polysulfone and polyethersulfone), raising significant environmental concerns. In this study, we developed eco-friendly TFC membranes using biodegradable cellulose as the support and a bio-derived sugar-based monomer for the selective layer. Green solvents, PolarClean® and 2-methyltetrahydrofuran, were employed as sustainable alternatives to conventional solvents. The optimized membrane achieved outstanding performance, with a water permeance of 66.5 L m−2 h−1 bar−1 and 99.8 % CR rejection, while maintaining low salt rejection (4.4 % for NaCl and 9.3 % for Na2SO4). Moreover, the polyester selective layer exhibited excellent chlorine resistance and robust mechanical stability, emphasizing its potential for practical use. This work demonstrates a sustainable platform for fabricating green membranes tailored for dye/salt separation.