Incorporating covalent organic framework nanosheets via solvent-exchange strategy boosted hybrid membrane dehydration performance

The uniform dispersion of fillers within the polymer matrix is crucial for the fabrication of hybrid membranes. In this study, we proposed a facile solvent-exchange strategy for developing a hybrid membrane based on a covalent organic framework (COF, TpPa-1), specifically designed to enhance filler distribution in in the membrane towards pervaporation dehydration of butanol/water mixtures. The TpPa-1 nanosheets prepared via a glycerol-mediated method and their hybrid membranes were characterized using SEM, TGA, XPS, BET, FT-IR, and XRD techniques. Molecular dynamics (MD) results revealed that the solvent-exchange strategy significantly enhanced COF nanosheets (CONs) dispersion by removing glycerol. Pervaporation dehydration performance demonstrated significant improvements in total flux and separation factor when TpPa-1 nanosheets and sodium alginate (SA) were integrated, compared to a pure SA membrane. The optimized COF-SA hybrid membrane achieved a total flux of 1753 g/m²·h and a dehydration separation factor of 4687 at 40 °C for 90 wt% butanol/water mixtures. This study not only highlights a viable approach for membrane solvent dehydration but also provides a design strategy for creating hybrid membranes with uniform filler dispersion.