Fabrication of Dense Polyester Nanofiltration Membranes with Superior Fouling and Chlorine Resistance: Effect of Polyol Monomer Properties and Underlying Mechanisms

Polyester (PE) membranes have attracteda great deal of attentiondue to their notable chlorine resistance and antifouling ability.Despite the fact that various polyhydroxy molecules have been usedas aqueous monomers, few have been capable of attaining a PE membranewith a high separation ability of small molecular organics, and relevantmembrane formation mechanisms are still unclear. In this study, threerelatively dense polyester membranes were obtained by optimizing reactionconditions, using erythritol, xylitol, and isomalt, all of which showedsatisfying separation capacities and the potential to be used forapplications requiring high rejections of small molecular organics,such as drinking water treatment. Comprehensive characterization andmolecular simulation were conducted to elucidate the process of formationof PE membranes prepared with different polyol monomers. It was demonstratedthat the physicochemical properties and separation performance ofPE membranes were jointly affected by the molecular size of polyolsas well as their hydroxyl density and activity. Compared with thecommercial NF270 and lab-made polyamide membranes, all three PE membranesshowed application advantages, including better chlorine resistanceand antifouling performance. This study provides references for therational selection of monomers and performance optimization in thedevelopment of high-performance PE membranes.