Constructing rapid diffusion pathways in ultrapermeable hybrid membranes by hierarchical porous nanotubes

摘要

Constructing mass transfer highways in polymer membranes via fillers with hierarchical porous and/or hollow structure is an effective approach to enhance their separation performance. In this study, novel hierarchical porous organosilica nanotubes (HPSiNT) were designed and incorporated into Pebax matrix to fabricate hybrid membranes for organic solvent separation. The HPSiNT, with plenty of micropores (similar to 1.6 nm) on the wall of nanotubes and atomically smooth meso-inner channels (similar to 6 nm), offer abundant entrances and rapid diffusion pathways for penetrant molecules, thus endowing the hybrid membranes with superior separation performance. Employing thiophene/n-octane feed solution as a model system, the hybrid membrane that consists of 2 wt% HPSiNT exhibited a high permeation flux of 19.0 kg/(m(2) h) (increased by 66.8% compared with pure Pebax membrane) and thiophene/n-octane enrichment factor of 5.5 (increased by 11.7% compared with pure Pebax membrane), respectively. Introducing hierarchical nano-channels in polymeric matrices could open a new avenue to designing hybrid membranes with high permeation flux. (C) 2018 Elsevier Ltd. All rights reserved.