Modeling the simultaneous role of interface layer thickness and particle shape in the gas separation properties of composite membranes

For the first time in this paper, using the analogy between heat transfer and mass transfer, a new model is proposed to simultaneously consider the effects of the particle shape and the thickness of the dense interface layer, aint, on the gas separation performance of polymeric composite membranes. The main idea is the calculation of the interface layer without tedious and complicated experiments. The values of a(int) parameter obtained from fitting the new model on both CO2 and CH4 permeability data are almost the same for each composite membrane. The results demonstrate that the aint parameter is independent of the type of gas molecules and is only dependent on the particle/polymer interfacial interactions. To evaluate the validity of existing and new theoretical models, the average absolute relative error (%AARE) values between experimental gas permeability of composite membranes and the model predictions are calculated. The %AARE value for the new model is lower than 3%, indicating the good prediction accuracy of the new model. While, the values of %AARE for other studied models are up to 89%.