Carbon Dioxide absorption by asymmetric PEI hollow fibermembrane contactor

Porous asymmetric polyetherimide (PEI) hollow fiber membrane were fabricated via a phaseinversionmethod using methanol (0 and 2 wt.%) as additive in the dope solution. An aqueous solution of 1-methyl-2-pyrrolidone (90 wt.%) was used as bore fluid to prevent forming inner dense skin layer. The effectof the additive on the resulting membrane structure, surface porosity, pore size, critical water entry pressure,collapsing pressure and CO2 absorption performance by distilled water in a gas-liquid membrane contactorsystem were investigated. Cloud point diagrams indicated that the precipitation rate of the polymer dopesincreased by increasing additive concentration in the spinning dope. Results of gas permeation tests showedthat methanol with 2 wt.% provided the membranes with the larger pore size. The cross-section of themembranes was examined via a scanning electron microscopy. Methanol (2 wt%) in the spinning dopeprovided the membrane structure with a sublayer with finger-like macrovoids, originating from inner andouter surfaces of the hollow fiber and extending to the middle section of the hollow fiber wall, which resultedin a larger pore size and higher CO2 absorption rate than the other PEI hollow fiber membrane.

Keywords:

Polyetherimide , hollow fiber membrane contactor , CO2 absorption , Glycerol