Hollow fiber ultrafiltration (UF) membranes were prepared using
Polyethersulfone (PES), alcohol (n-Propanol) as additive and N, N-dimethylacetamide
(DMAc) as a solvent. Asymmetric hollow fiber UF membranes were spun by wet phase
inversion method from 17 wt% solids of PES/additive/NMP solutions. The alcohol
additive was n-Propanol while the external coagulant was water. Effects of n-Propanol
concentrations in the dope solution on morphology and separation performance of PES
hollow fiber UF membranes were investigated. UF membranes were characterized in
terms of scanning electron microscope (SEM) while UF experiments were conducted
using polyethylene glycol (PEG20,000MW) and poly (vinyl pyrrolidone) (PVP
40,000MW), as a solute. It was found that the PES UF membrane morphology changed
from long two finger-like structure through a short two finger-like structure to the two
void-like structure as n-propanol concentration in the dope solution increased from 5 to
20 wt % using water as a bore fluid; pure water permeation fluxes (PWP) increased from
47 to 201 L/ while rejections of PEG MW20,000 and PVP MW40,000 for wetspun
PES hollow fiber membranes were decreased with the increasing of n-propanol
concentration up to 20%. Using above method, PES hollow fiber UF membrane with
high pure water permeation flux could be prepared while the molecular weight cut-off of
PES hollow fiber membranes is approximately 20,000.