Ultra-fast molecular sieving in ZIF-67 and cellulose nanofibers based thin-film nanocomposite membrane

Membranes based on two-dimensional (2D) materials often show great separation efficiency and therefore have great potential in the treatment of dye wastewater. However, improving the water flux of 2D material-based membranes remains a challenge. In this work, 2D ZIF-67/CNF membranes were prepared on a polyether sulfone (PES) support layer via a simple extraction filtration method. The added CNF intertwined with 2D ZIF-67 nanosheets and formed an interlocked stacked laminar flow structure, which improved both the water flux and stability of the thin-film nanocomposite (TFN) membranes. The optimized membrane showed a water flux of 357.8 L m − 2  h − 1  bar − 1 , and its rejections of four dyes (Direct Red 80, Methyl Blue, Alkali Blue 6B and Congo Red) were all above 99.8 %. Furthermore, the optimized membrane maintained a rejection of 97 % after 8 h of continuous operation, indicating that the facile mixing of nanofibers into nanosheets can be considered a promising strategy for preparing TFN membranes for dye wastewater treatment.