Rigorous modeling of gas permeation behavior in facilitated transport membranes (FTMs); evaluation of carrier saturation effects and double-reaction mechanism

In this work, a general model for the gas permeation behavior of facilitated transport membranes (FTMs) has been developed. The importance of developing a clearer understanding of FTM permeation behavior by introducing a detailed two-dimensional FTM model was demonstrated. This model accounts for the effects of partial pressure on permeance by considering the carrier saturation-state phenomenon and reaction-diffusion portions in FTMs. The model is based on a first order double-step reaction mechanism with respect to the role of the concentration of zwitterion ions in the facilitated transport of CO2. It is shown here that the individual values of reaction constant rates and diffusion coefficients of components in the chemical reaction, which belong to the FTM condition, have been determined by the FTMs' permeability and were not guessed or calculated. Overall, this work provides a method for the more reliable use of models to understand and design of FTMs, and to better comprehend the large and growing body of experimental data on these kinds of membranes. (c) 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.