(463g) Organic Solvent Nanofiltration Membranes Developed By Mussel-Inspired Strategy

Most of the reported nanocomposite solvent nanofiltration (OSN) membranes were fabricated by interfacial polymerization or direct coating method. Interfacial polymerization suffers sophisticated multistep fabricating steps, while direct coating usually yields separation layer with thickness up to tens of micrometers. Herein, a mussel-inspired polydopamine (PDA) coating layer has been first explored as a separating layer for organic solvent nanofiltration (OSN). A PDA based separating layer was constructed on polyimide (PI) support via dopamine coating. The subsequent membrane was then treated with 1,6-hexanediamine for cross-linking on both the PDA layer and PI support. After an optimized coating time of 4 h, the resultant membrane showed an EtOH permeance of 0.91 L m−2 h−1 bar−1 and a RB rejection of 99%. More importantly, the composite membrane also exhibited good performance for dyes separation from a wide range of solvents including challenging polar aprotic and strongly swelling solvents, such as dimethylformamide and acetone. Furthermore, to make OSN more economically and efficiently via deposition approach, we also develop a mussel-inspired co-deposition strategy to fabricate nanocomposite OSN membranes, which possess the optimized ethanol (EtOH) permeance of 1.26 L m−2 h−1 bar−1 with a rejection of 99% to Rose Bengal (RB). Particularly, the nanocomposite membrane demonstrated stable performances during a two-day long term test in DMF for RB concentration. In addition to providing a highly-efficient way to high-performance OSN membrane, this work may stimulate the bio-inspired design of advanced nanocomposite membranes for environmental applications.