Layer-by-layer assembly of TpPa−SO 3 H/TpEB composite membranes for nanofiltration

Layer-by-layer assembled covalent organic framework membranes were fabricated by alternately depositing negatively charged TpPa−SO 3 H and positively charged TpEB nanosheets onto a pretreated nylon support via vacuum filtration. The resulting TpPa−SO 3 H/TpEB composite formed a compact selective layer stabilized by electrostatic attraction and [Formula: see text]–[Formula: see text] stacking. By optimizing the layer number and deposition density, the bilayer membrane achieved 99.3% Congo Red rejection with a permeance of 86.0 L m[Formula: see text] h[Formula: see text] bar[Formula: see text] and >99% rejection for multiple dyes, with a molecular weight cutoff of 461.38 Da.