Here, BaxSr1-xCo0.8Fe0.2O0.3-δ (x = 0.2, 0.5, 0.8) dense membranes were prepared by using a combined EDTA and citrate complexing method. In previous work, the effects of sintering temperature, sintering dwell-time and pressing pressure upon the microstructure and theoretical density of the membranes were examined and the best corresponding values were reported to be 1100C, 8–9h and 200–250MPa, respectively. The effects of temperature (650–950C), feed flow rate (100–200cm³/min), sweep gas flow rate (40–80cm³/min) and membrane thickness (4–5mm) on oxygen permeation behavior of the BaxSr1 − xCo0.8Fe0.2O0.3 − δ membranes were now investigated. Also, a mathematical model based upon the Nernst–Planck equation was developed in order to predict oxygen permeation through the perovskite-type membranes. Both bulk diffusion and surface reactions were incorporated into the model. It was observed that surface reactions were not elementary and a correction term should be introduced into the model to compensate this effect. Also, using a dimensionless Reynolds number, effect of feed flow rate on oxygen flux was taken into account. With aids of these modifications, it was realized that, there was a reasonable agreement between predicted results and experimental data with correlation coefficient (R) of higher than 0.960 and mean squared relative error (MSRE) of lower than 0.022 for all the membranes. Oxygen vacancy bulk diffusion coefficient (Dv), surface exchange rate constants (kf and kr), contribution of each resistance to oxygen permeation and characteristic thickness (Lc) of the BSCF membranes were also estimated.

Oxygen Permeation of BaxSr1-xCo0.8Fe0.2O3-δ Perovskite-Type Membrane: Experimental and Modeling. A.Ghadimi, M.A.Alaee, A.Behrouzifar, A.A.Asadi, T.Mohammadi: Desalination, 2011, 270[1-3], 64-75