Received 24 January 2011; revised 27 March 2011; Accepted 27 March 2011. Available online 6 April 2011.
A SrCo0.8Fe0.2O3 impregnated TiO2 membrane (TiO2–SrCo0.8Fe0.2O3 membrane) was successfully prepared using a sol–gel method in combination with a wet impregnation process. The membrane was subjected to a single gas permeance test using oxygen (O2) and nitrogen (N2). The TiO2 membrane was immersed in the SrCo0.8Fe0.2O3 solution, dried and then calcined to affix SrCo0.8Fe0.2O3 into the membrane. The effect of the acid/alkoxide (H+/Ti4+) molar ratio of the TiO2 sol on the TiO2 phase transformation was investigated. The optimal molar ratio was found to be 0.5, which resulted in nanoparticles with a mean size of 5.30 nm after calcination at 400 °C. The effect of calcination temperature on the phase transformation of TiO2 and SrCo0.8Fe0.2O3 was investigated by varying the calcination temperature from 300 to 500 °C. X-ray diffraction spectroscopy (XRD) and Fourier transform infrared (FTIR) analysis confirmed that a calcination temperature of 400 °C was preferable for preparing a TiO2–SrCo0.8Fe0.2O3 membrane with fully crystallized anatase and SrCo0.8Fe0.2O3 phases. The results also showed that polyvinyl alcohol (PVA) and hydroxypropyl cellulose (HPC) were completely removed. Field emission scanning electron microscopy (FESEM) analysis results showed that a crack-free and relatively dense TiO2 membrane (∼0.75 μm thickness) was created with a multiple dip-coating process and calcination at 400 °C. The gas permeation results show that the TiO2 and TiO2–SrCo0.8Fe0.2O3 membranes exhibited high permeances. The TiO2–SrCo0.8Fe0.2O3 membrane developed provided greater O2/N2 selectivity compared to the TiO2 membrane alone.