Development of asymmetric polysulfone hollow fiber membrane contactor for CO2 absorption

Porous asymmetric polysulfone (PSf) hollow fiber membranes were fabricated via wet spinning process. A mixture of 1-methyl-2-pyrrolidone (NMP) and distilled water (90 wt.% NMP) was used as bore fluid to make hollow fiber membranes without inner skin layers, whereas glycerol with 2 and 4 wt.% was used as additives to the spinning dope. The effect of the additives concentration on the structure, surface porosity, pore size, critical water entry pressure (CEPw), and CO2 absorption flux of the fabricated membranes were investigated. The cross-section and inner surface of the membranes were examined via scanning electronic microscopy (SEM). Using glycerol as the additive in the spinning dope provided the membrane structure with a thin finger-like and a thick sponge-like layer, which resulted in a high CEPw and CO2 absorption rate. Results of gas permeation tests showed with increasing glycerol concentration the N2 permeance increase significantly and the wetting resistance decrease slightly. CO2 absorption by distilled water was conducted through the gas–liquid membrane contactors. By using 4% glycerol in the spinning dope, the PSf membrane showed a CO2 flux of approximately 57% higher than the PSf membrane with 2% glycerol at the absorbent flow rate of 200 ml/min.

► Different amounts of glycerol were used as additive to fabrication of PSf HFM.
► Average pore size increased by increasing additive in the spinning dope.
► The PSf HFM was used in contactor application for absorption of CO2 with water.
► Glycerol at 4% concentration provided the membrane structure that enhanced CO2 flux.