Covalent organic frameworks hybird membrane with optimized mass transport nanochannel for aromatic/aliphatic mixture pervaporation

Building up selective mass transfer channels in polymeric membranes is a promising strategy to fabricate effective separation membranes. Herein, a thioether-functionalized hydrazone-linked covalent organic framework, COF-LZU8, pre-modified by Ag ion, was incorporated for constructing aromatic selective channels within a commercial poly (ether-block amide) (Pebax 2533) membrane. The inside nanochannels of resulting membrane were effectively confirmed by measuring the affinity and the selective free volume to toluene via quartz crystal microbalance and low-field nuclear magnetic resonance. Owing to the selective channels, the Ag-COF-LZU8/Pebax membrane presented a considerably enhanced performance for toluene/n-heptane separation comparing with pristine Pebax membranes. The optimized membrane could perform a permeation flux of 293 g/m(2)h and a separation factor of 4.03 for the separation of 50 wt% toluene/n-heptane mixture.