The effects of surface modifications on preparation and pervaporation dehydration performance of chitosan/polysulfone composite hollow-fiber membranes

Chitosan/polysulfone (Ch/PSf) composite hollow-fiber membranes were prepared from casting a γ-(glycidyloxypropyl)trimethoxysilane (GPTMS)-containing chitosan solution on poly(styrene sulfonic acid)-grafted (PSSA) polysulfone hollow-fiber membranes. The presence of PSSA chains on the surface of the PSf hollow-fiber membrane formed chemical bonding with chitosan chains to provide good adhesion between the chitosan layer and the PSf substrate, so as to improve the stability of the composite hollow-fiber membranes. The thickness of the chitosan layer and the pervaporation dehydration characteristics of the composite membranes were dependent on the concentrations of the chitosan coating solutions. The composite hollow-fiber membrane Ch-1.5/PSf-PSSA, which was prepared from coating with a 1.5 wt.% chitosan solution, exhibited a permeation flux of 128 g/m2 h and a separation factor of 78 in the pervaporation dehydration on a 70 wt.% isopropanol aqueous solution at 25 °C. The membrane still survived in a 30-day test to warrant its stability in long-term operations.