In this study, thin-film composite (TFC) hollow fibers (HFs) were fabricated by an in-situ coating of polyamide
layer on the lumen side of PVC/PC blend substrates for desalination by forward osmosis (FO). Particularly, the
substrate HFs were spun at two air gap distances of 2 and 6 cm, to investigate the effect of the air-gap distance on
the FO performance. The substrate HFs were characterized by pure water flux measurement, FESEM, and gas
permeability test. The Interfacial polymerization (IP) method was then utilized for coating polyamide (PA) layer
on the lumen surface of the substrate to fabricate TFC HFs. The TFC HFs so fabricated were also characterized by
FESEM, before their FO performance was tested. Furthermore, the effect of HF length on the FO flux was
investigated. The results showed that the novel TFC HFs exhibited good FO performance. The longer the air gap
distance, the better becomes the FO performance in terms of simultaneous water flux and alginate fouling
resistance, while the effect of the HF length remains a controversial issue.