A membrane-based gas-liquid contacting process was evaluated in this work for CO2 removal from flue gases. The absorption of CO2 from a CO2-N-2 mixture was investigated using a commercial hollow fiber membrane contactor and water or diethanolamine as absorbing solvents. Significant CO2 removal (up to 75%) was achieved even with the use of pure water as absorbent. By using aqueous amine solutions and chemical absorption, mass transfer improved, and CO2 removal was nearly complete (similar to99%). A mathematical model was developed to simulate the process and it was validated with experimental data. Results show that membrane contactors are significantly more efficient and compact than conventional absorption towers for acid gas removal. (C) 2003 Elsevier Ltd. All rights reserved.