A mimic enzyme promoted facilitated transport membrane was developed and optimized for post-combustion CO2 capture. This composite membrane has a thin dense polyvinyl alcohol (PVA) selective layer containing a low molecular weight mimic enzyme and a polysulfone (PSI) ultrafiltration porous support. The selected mimic enzyme (i.e., Zn-cyclen) was characterized by HNMR1, ESI-MS and dissociation constant (pKa). The membrane morphology was studied by scanning electron microscope (SEM). The effect of mimic enzyme loading and the pH value of the membrane casting solution was investigated. The optimal Zn-cyclen loading of 5 mu mol/g PVA and a pH value of 9 were determined. The influence of humidity on the performance of the membrane was also studied by conducting experiments at variable relative humidity levels (i.e., 50-100%). This membrane showed a CO2 permeance of 0.69 [m(3)(STP)/(m(2) bar h)] and a CO2/N-2 selectivity of 107, which is significantly higher than that of a PVA membrane without mimic enzyme operating under the same conditions. (C) 2015 Elsevier B.V. All rights reserved.