CO2 is a main greenhouse gas emission causing global warming and other environmental issues, which is mainly emitted from the fossil fuels combustion or utilization. Membrane absorption is a novel CO2 capture method that combines the advantages of chemical absorption and membrane separation. In this paper, a comprehensive 2D symmetric model for a CO2-piperazine (PZ)-membrane absorption process was proposed. PZ solutions showed high CO2 capture performance due to high chemical reaction rate constant. Decreasing the gas flowrate and increasing the absorbent flowrate promoted the CO2 absorption efficiency. On the other hand, varying the membrane contactor properties could also affect the capture of CO2. 0.28 m/s gas velocity, 0.08 m/s absorbent velocity, 20% CO2 in gas mixture, and 0.94 mol/L PZ were recommended as the optimum conditions after the parametric study. This numerical model is reliable for potential use in CO2-absorbent-membrane absorption systems. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.