Performance evaluation of composite and microporous gas–liquid membrane contactors for CO2 removal from a gas mixture

• Non-porous hollow fiber contributed to reducing the wetness of the membranes.
• Performance decline was attributed to pores wetting during the experiments.
• Composite hollow fiber allows the use of total surface area available for permeation.
• The use of chemical absorbents increased the CO2 removal.

Hollow fiber membrane contactors with microporous polypropylene (PP) and composite polytetrafluoroethylene/polyethersulfone (PTFE/PES) were used for carbon dioxide (CO2) removal from a gas mixture. The composite membranes exhibited higher efficiency than the microporous membranes, which was related to prevention of pore wetting due to the PTFE present in the top layer of the membrane. For both type of contactors, it was investigated the influence of liquid flow rate, temperature and kind of absorbent on the CO2 removal. A better performance of CO2 transfer into the liquid phase was observed by increasing the liquid flow rate, by using a reacting absorbent (sodium hydroxide) and by decreasing the liquid temperature.