Decorating loose defect-free hybrid selective layer on smooth
intermediary:an effective way of forward osmosis membrane
Abstract
A novel composite forward osmosis (FO) membrane was fabricated by
introducing a chitosan (CS) sublayer between nanofibers and polyamide
(PA) layer, which was beneficial to forming thin and defect-free PA
layer and improved binding strength between substrate and selective
layer. Results exhibited low reverse salt flux (0.73 gMH) while
maintained high water flux (85.4 LMH), which were better than that in
other reports. In order to further improve permeability of membranes,
oxidized multiwall carbon nanotubes (OMWNTs) were added into PA layer
based on the optimized sublayer. The crosslinking degree of PA layer was
reduced, leading to loose PA layers, which promoted the increase of
water flux. After modifying, water flux reached 96.9 LMH without
sacrificing salt rejection. It was worth mentioning that PAN/CS
composite FO membrane, which could adjust microstructure of support
layer and selective layer respectively, may provide a promising way for
preparing membranes with anticipated separation performance.